JPH04344314A - Magnetic tape recording device - Google Patents

Abstract

PURPOSE:To accurately detect clogging in the magnetic gap formation part of a rotary magnetic head in recording operation when recording signals composed of intermittently ranging unit partition signal components which are formed based on a signal to be recorded are recorded on a magnetic tape with two rotary magnetic heads. CONSTITUTION:Every time when two rotary magnetic heads 41 and 42 arranged in 45 deg. rotary angle space are rotated, the unit partition signal components in the recording signal are supplied alternately. A reading output detection part which detects the reading output from the recording track to be obtained from the following rotary magnetic head 42 after a recording track is formed on a magnetic tape 45 by this preceding rotary magnetic head 41 and a clogging detection signal formation part which forms a signal corresponding to the clogging about the rotary magnetic heads 41 and 42 based on the detection output from the reading output detection part are provided.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention uses a plurality of rotating magnetic heads to generate a recording signal based on a signal to be recorded, such as a video signal, along the outer circumferential surface of a tape guide cylinder. The present invention relates to a magnetic tape recording device that records on a running magnetic tape.

0002

2. Description of the Related Art A so-called video tape recorder, which is a device for recording a video signal on a magnetic tape or reproducing a video signal from a magnetic tape on which the video signal has been recorded, is
The tape guide cylinder includes a tape guide cylinder having an outer circumferential surface portion that serves as a running guide for the magnetic tape, and a rotating magnetic head disposed inside the tape guide cylinder. It is assumed that the magnetic tape runs on the outer circumferential surface of the tape guide cylinder, and in this case, the magnetic tape is wound around the outer circumferential surface of the tape guide cylinder at a preset wrapping angle. It is assumed to take on a state. The tape guide cylinder is, for example, divided in the direction of its central axis to form a fixed part and a rotating part, and the rotating part is rotated with respect to the fixed part at a preset rotation speed. The rotating magnetic head is, for example, attached to the rotating part of the tape guide cylinder and positioned between the fixed part and the rotating part of the tape guide cylinder, and rotates with the rotation of the rotating part of the tape guide cylinder. , with the magnetic gap forming portion facing the outer circumferential surface portion of the tape guide cylinder, and during each rotation period, scanning the magnetic tape running on the outer circumferential surface portion of the tape guide cylinder obliquely with respect to its traveling direction; Records signals on magnetic tape or reads signals from magnetic tape.

Recording of video signals on a magnetic tape using such a tape guide cylinder and rotary magnetic head involves the recording of a large number of tapes, each extending at a predetermined angle of inclination with respect to the longitudinal direction of the magnetic tape. Recording tracks are arranged in parallel, and usually one field period of a video signal is recorded on each recording track. Therefore, during a recording operation, a rotating magnetic head that scans a magnetic tape diagonally with respect to the traveling direction during one rotation period records one field period of video signals on the magnetic tape for each rotation. A recording track of a book is formed, and during a reading operation, the magnetic tape is scanned along the recording track formed on the magnetic tape every rotation to read one field period of the video signal.

[0004] Regarding such video tape recorders, many systems have been proposed with different specifications regarding the mechanism, specifications regarding signal recording and signal playback operations, specifications regarding operation control, etc., but one of them is As a standard video tape recorder that complies with
The tape winding angle) is, for example, 180 degrees, and the rotation speed of the rotating part in the tape guide cylinder (hereinafter referred to as cylinder rotation speed), that is, the rotation speed of the rotating magnetic head is approximately 29.97 rps. There is one in which the number of magnetic heads is two and they are arranged with a rotation angle interval of 180 degrees. Such a standard video tape recorder belongs to a category in which the diameter of the tape guide cylinder is relatively small, and the tape guide cylinder and rotary magnetic head employed therein are different from the standard tape guide cylinder and the rotary magnetic head, respectively. It is considered a standard rotating magnetic head.

[0005] Furthermore, in order to further reduce the size and weight of the standard video tape recorder as described above, the diameter of the tape guide cylinder is made smaller than that of the standard tape guide cylinder. It has been proposed to construct a compact video tape recorder that is compatible with commercially available video tape recorders. Regarding such small video tape recorders, from the viewpoint of compatibility with standard video tape recorders regarding the recording format on the magnetic tape, (1) the length of the recording track formed on the magnetic tape is the same as that of the standard video tape recorder. (2) The period for one field period of the video signal recorded on the magnetic tape is equal to the length of the recording track formed on the magnetic tape by a standard video tape recorder. Therefore, it is required that the period be equal to the period of one field period of the video signal recorded on the magnetic tape.

Therefore, for a small video tape recorder, let the ratio of the diameter of the tape guide cylinder to that of a standard video tape recorder be a, the ratio of the tape winding angle be b, and the ratio of the cylinder rotation speed be c. (1) and (2)
In order to satisfy the following conditions, it is necessary that the relationship a·b=1, b/c=1 hold, and that the number of rotating magnetic heads be an even number of 4 or more. So, for example,
a = 2/3, b = c = 3/2, and the number of rotating magnetic heads was selected to be 4, thereby making the diameter of the tape guide cylinder 40 mm 2/3 ≒ 26.67 m.
m, tape wrapping angle is 180 degrees 3/2 = 270 degrees, cylinder rotation speed is 29.97 rps 3/2 ≒ 44.95
A small video tape recorder with a speed of 5 rps and four rotating magnetic heads will be constructed.

However, in a small video tape recorder constructed in this way, the number of rotating magnetic heads is
This is an increase compared to a standard video tape recorder, and it is necessary to provide four tape guide cylinders. Assembling four independent rotating magnetic heads involves considerable difficulty, and there is also a risk that the mounting accuracy of the four rotating magnetic heads may not be good. Furthermore, for example, fast forward playback (Cue playback), rewind playback (Rev playback),
It is considered extremely difficult to add a rotating magnetic head for variable speed playback, which is used for variable speed playback such as (view playback) and still image playback (still playback), and as a result, so-called noiseless variable speed playback is no longer possible. It ends up.

Therefore, as mentioned above, for example, the diameter is set to 40
Compared to a standard video tape recorder having a standard tape guide cylinder with a diameter of approximately 26 mm and two standard rotating magnetic heads with a rotational speed of approximately 29.97 rps, the diameter of the tape guide cylinder is, for example, approximately 26 mm. .67 mm, yet still be compatible with standard video tape recorders in terms of recording format on magnetic tape, without increasing the number of rotating magnetic heads. A tape recorder has also been proposed by the applicant (Japanese Patent Application No. 3-90431). In such a small video tape recorder with two rotating magnetic heads, the diameter of the tape guide cylinder is, for example, the diameter of a standard tape guide cylinder (40 m
m), that is, approximately 26.67 mm,
The tape wrapping angle is 3/2 times the tape wrapping angle (180 degrees) of a standard video tape recorder, that is, approximately 27
0 degrees, and the rotation speed of the rotating magnetic head is twice the rotation speed of the standard rotating magnetic head (approximately 29.97 rps), that is,
The rotation angle interval between the two rotating magnetic heads is approximately 45 rps, which is smaller than the rotation angle interval (180 degrees) between two standard rotating magnetic heads.
It is said that it was selected at the same time. Under such circumstances, during the recording operation, the video signal to be recorded is time-axis compressed at a predetermined time compression rate for each one field period, and the video signal is compressed in the time axis for each one field period. Each of the video signals forms a unit segment video signal component, and a recording video signal consisting of the unit segment video signal components intermittently continues,
recorded on magnetic tape by two rotating magnetic heads,
In addition, during playback operation, the recording signals recorded on the magnetic tape are read alternately by two rotating magnetic heads, and the unit segment image obtained in the read output signal from each of the two rotating magnetic heads is Each of the signal components is time-axis expanded with a time expansion rate corresponding to the time compression rate during the recording operation, so that a reproduced video signal is obtained.

[0009] Constructed in this way, the diameter is approximately 26.6
A small video tape recorder equipped with a small tape guide cylinder with a diameter of 7 mm and two rotating magnetic heads with a rotation angle interval of approximately 45 degrees has a tape guide cylinder diameter that is equal to that of a standard video tape recorder. Although the diameter of the magnetic tape is smaller than that of the magnetic tape, the number of rotating magnetic heads is not increased, and the recording format on the magnetic tape is compatible with standard video tape recorders. It turns out.

0010

[Problem to be Solved by the Invention] A video tape recorder including a small-sized video tape recorder equipped with a small-sized tape guide cylinder as described above and two rotating magnetic heads having a rotation angle interval of, for example, approximately 45 degrees. In a tape recorder, the magnetic gap forming part of the rotating magnetic head generally becomes clogged with magnetic particles generated when the magnetic layer of the magnetic tape is scraped, causing the magnetic gap to become clogged. There is a risk that the device may be in a state of so-called clogging, where it will no longer function normally. When a rotating magnetic head in which clogging has occurred in the magnetic gap forming part is used for recording signals on a magnetic tape, the rotating magnetic head may not record signals on the magnetic tape, or the rotating magnetic head may not record signals on the magnetic tape. This may lead to a situation where the level of the recorded signal becomes abnormally low. Therefore,
If clogging occurs in the magnetic gap forming portion of a rotating magnetic head used for recording signals on a magnetic tape, this is accurately detected and the magnetic gap forming portion is cleaned. To this end, it is effective to appropriately detect clogging at the magnetic gap forming portion of the rotating magnetic head during the recording operation of recording signals on the magnetic tape. .

[0011] In order to appropriately detect clogging in the magnetic gap forming portion of a rotating magnetic head that is in the process of recording a signal on a magnetic tape, the rotating magnetic head that records a signal on the magnetic tape records data on the magnetic tape. It is required that the recorded signal be read from the magnetic tape immediately after its recording. Therefore, for example, a rotating magnetic head for reading may be made to follow a rotating magnetic head for recording signals on a magnetic tape.
It is conceivable that the preceding rotating magnetic head may record signals on the magnetic tape, and the following rotating magnetic head may read the signals recorded by the preceding rotating magnetic head at the same time. In this case, the structure of the rotating magnetic head becomes extremely complicated, and the level of the recording signal supplied to the rotating magnetic head used for recording signals on the magnetic tape is usually higher than the level of the signal from the magnetic tape. The level of the read output signal obtained from the rotary magnetic head for reading is significantly higher than that of the read output signal, and the recording signal has a high level through the signal supply circuit system and signal extraction circuit system connected to each rotary magnetic head. The resulting crosstalk component is mixed into the read output signal of the rotating magnetic head that reads the signal from the magnetic tape, making it impossible to obtain an appropriate read output signal from the rotating magnetic head that reads the signal from the magnetic tape. As a result, it is not possible to accurately detect clogging at the magnetic gap forming portion of the rotating magnetic head during the recording operation of recording signals on the magnetic tape.

[0012] Accordingly, among the conventionally proposed video tape recorders, those in which clogging in the magnetic gap forming portion of the rotating magnetic head during the recording operation of recording signals on the magnetic tape can be accurately detected are as follows: It is in a situation where it cannot be found.

In view of the above, the present invention provides a small-sized video tape recorder comprising, for example, the above-mentioned small-sized tape guide cylinder and two rotating magnetic heads having a rotation angle interval of, for example, approximately 45 degrees. A recording signal consisting of an intermittent series of unit segment signal components obtained based on a video signal to be recorded is recorded on a magnetic tape by two rotating magnetic heads. A magnetic tape recording device capable of forming a video tape recorder in which clogging in a magnetic gap forming portion of a rotating magnetic head during a recording operation for recording recording signals on a tape is accurately detected. The purpose is to provide.

[0014]

[Means for Solving the Problems] In order to achieve the above-mentioned object, a magnetic tape recording device according to the present invention generates a recording signal in which unit segment signal components are intermittently connected based on a signal to be recorded. A first recording signal forming section for scanning a magnetic tape that is rotated simultaneously with a recording signal forming section arranged at a predetermined rotation angle interval and that runs along an outer peripheral surface portion of a tape guide cylinder during each rotation period. and second
For each rotation of the rotary magnetic head and the first and second rotary magnetic heads, unit division signal components in the recording signal obtained from the recording signal forming section are sequentially alternately sent to the first and second rotary magnetic heads. and a recording signal supply section for forming a recording track on the magnetic tape by the first or second rotary magnetic head to which the unit division signal component is supplied; During the rotation period of the first and second rotating magnetic heads during which a recording track is formed on the magnetic tape by the rotating magnetic head, after the recording track is formed on the magnetic tape by the first rotating magnetic head. , a read output detection section that detects a read output signal from the recording track obtained from the second rotary magnetic head, and a read output detection section that detects a read output signal obtained from the read output detection section, and a first and second rotary magnetic head that detects a read output signal obtained from the read output detection section. and a clogging detection signal forming section that forms a signal according to clogging for.

[0015]

[Operation] In the magnetic tape recording device according to the present invention configured as described above, for example, the video signal to be recorded is time-axis compressed at a predetermined time compression rate for each field period. It is assumed that each of the time-axis compressed video signals for one field period forms a unit segment signal component, and a recording signal made up of the unit segment signal components intermittently connected is, for example, a 45-degree angle. The magnetic tape is scanned by first and second rotating magnetic heads arranged at rotational angle intervals and simultaneously rotated to scan the magnetic tape traveling along the outer circumferential surface portion of the tape guide cylinder during each rotation period. recorded. At this time, the first and second rotary magnetic heads are rotated with the first rotary magnetic head leading and the second rotary magnetic head following with a rotation angle interval of 45 degrees, and Each of the first and second rotary magnetic heads is alternately supplied with each of the unit division signal components forming the recording signal, and the first or second rotary magnetic head to which the unit division signal component is supplied is alternately supplied with each of the unit division signal components forming the recording signal. Each of the unit division signal components is sequentially recorded by a rotating magnetic head forming a recording track on the magnetic tape.

[0016] During the rotation period of the first and second rotating magnetic heads during which recording tracks are formed on the magnetic tape by the preceding first rotating magnetic head, magnetic recording is performed by the first rotating magnetic head. After a recording track is formed on the tape, a second rotating magnetic head that follows partially scans the recording track formed by the first rotating magnetic head, thereby obtaining readings from the second rotating magnetic head. The output signal is detected, and a clogging detection signal corresponding to clogging for the first and second rotary magnetic heads is formed based on the detected output signal obtained as a result. Therefore, clogging in the magnetic gap forming section of the first rotary magnetic head during a recording operation for recording recording signals on the magnetic tape, and furthermore, clogging from the recording track formed by the first rotary magnetic head to the recording Accurate detection of clogging in the magnetic gap forming portion of the second rotary magnetic head for reading signals will be performed.

[0017]

[Embodiment] FIG. 1 shows an example of a magnetic tape recording device according to the present invention. This example is supposed to record a color television signal conforming to the NTSC system. A video signal including a signal and a color signal is recorded on a magnetic tape together with an accompanying audio signal.

In FIG. 1, video signal input terminals 11 and 12 are supplied with a luminance signal Y and a carrier color signal C, which constitute a video signal in a color television signal based on the NTSC system, respectively. In addition, the audio signal input terminal 13
is supplied with an audio signal AU in a color television signal conforming to the NTSC system.

The luminance signal Y from the video signal input terminal 11 is digitized in an analog/digital (A/D) converter 14, and a digital luminance signal DY is obtained from the A/D converter 14 and stored in the field memory 15. supplied to Further, the carrier color signal C from the video signal input terminal 12 is digitized in the A/D converter 16, and
A digital carrier color signal DC is obtained from the /D converter 16 and supplied to the decoder 17. In the decoder 17, the digital red color difference signal DR and the digital blue color difference signal DB are individually taken out from the digital carrier color signal DC, and the digital red color difference signal DR and the digital blue color difference signal DB obtained from the decoder 17 are stored in the field memory 18, respectively. and is supplied to the field memory 19. Furthermore, the audio signal AU from the audio signal input terminal 13 is digitized by the A/D converter 20 , and the digital audio signal DA is obtained from the A/D converter 20 and supplied to the field memory 21 .

Field memories 15, 18, 19 and 2
1 are supplied with a write clock pulse PW and a read clock pulse PR sent from the timing pulse generator 22. The timing pulse generator 22 is supplied with a vertical pulse Pv synchronized with the vertical synchronization signal of the luminance signal Y supplied to the video signal input terminal 11 through the terminal 22A, and the timing pulse generator 22 receives the write clock pulse PW. is continuously transmitted as having a frequency ft, and the reading clock pulse PR is having a frequency of 4·ft/3, and the first of the two field periods forming each frame period of the luminance signal Y is From the start point synchronized with the vertical pulse Pv in the field period, for example, the period Ft・202.5/360 (where Ft represents the field period, for example, 1/60
The signal is transmitted for a period of Ft·3/4 from the time T1 after the period (seconds), and from the start point synchronized with the vertical pulse Pv in the second field period of the two field periods forming each frame period of the luminance signal Y. For example, from time T2 after the period Ft·247.5/360, the signal is transmitted for a period Ft·3/4.

Therefore, in the field memory 15, in accordance with the write clock pulse PW, the digital luminance signal DY is divided into F(n), F(n+1), F for one field period as shown in A in FIG. (n+2)
, ... are divided and written, and the written one field period F(n), F(n+1), F
(n+2), . . . are each read clock pulse P
It is read out according to R. At this time, since the frequency 4·ft/3 of the read clock pulse PR is set to 4/3 times the frequency ft of the write clock pulse PW, the digital luminance signal D read from the field memory 15
F(n), F(n+1), F( for one field period of Y
It is assumed that the time axis of each of n+2), . field memory 1.
5, as shown in B in FIG. 2, F(n) and F(n
+1), F(n+2), ... each has a time compression rate of 3/
Digital segmented time-base compressed luminance signals F(n)', F(n+2)', . . . which start from time T1 and continue for a period Ft·3/4, obtained by time-base compression with 4.
- A digital segmented time-base compressed luminance signal F(n-1)' starting from time T2 and continuing for a period Ft·3/4.
, F(n+1)', . The signal is supplied to the converter 23.

Further, in the field memories 18 and 19, the digital red color difference signal DR and the digital blue color difference signal DB are divided and written for each one field period according to the write clock pulse PW, and the written Each of the digital red color difference signal DR and the digital blue color difference signal DB for one field period is read out in accordance with the read clock pulse PR. In such a case, the frequency 4·ft/3 of the read clock pulse PR is set to 4/3 times the frequency ft of the write clock pulse PW, so that the digital red color difference signal read from the field memory 18 D.R.
It is assumed that the time axis is compressed at a time compression rate of 3/4 for each of one field period, and furthermore, the readout clock pulse PR is shortened by a period Ft·3/4 from each of time T1 and time T2. As a result, one of the digital red color difference signals DR is sent from the field memory 18.
A digital segmented time-base compressed color difference signal starting from time T1 and continuing for a period Ft·3/4, obtained by time-base compressing each field period at a time compression rate of 3/4, and a digital segmented time-base compressed color difference signal starting from time T2 and continuing for a period Ft·3/4. Digital segmented time-base compressed color difference signals lasting for a period of Ft·3/4 are sent out alternately and intermittently, and they are assumed to form a digital time-base compressed red color difference signal DR' as a whole. 24. Furthermore, since the frequency 4·ft/3 of the read clock pulse PR is set to 4/3 times the frequency ft of the write clock pulse PW, one field of the digital blue color difference signal DB read from the field memory 19 The time axis of each period is assumed to be compressed at a time compression rate of 3/4, and the read clock pulse PR is sent out for a period Ft·3/4 from each of time T1 and time T2. As a result, from the field memory 19, each of the digital blue color difference signals DB for one field period is time-axis compressed at a time compression rate of 3/4, and is obtained by time-axis compression for a period Ft·3/4 starting from time T1. The continuous digital segmented time-base compressed color difference signal and the digital segmented time-base compressed color difference signal starting from time T2 and continuing for a period Ft·3/4 are sent out alternately and intermittently, and they are digitally transmitted as a whole. The signal is supplied to the encoder 24 to form a time-base compressed blue color difference signal DB'. In the encoder 24, both the digital time-base compressed red color difference signal DR' and the digital time-base compressed blue color difference signal DB' are combined to form a digital time-base compressed carrier color signal DC' which is obtained intermittently. The digital time-base compressed carrier color signal DC′ obtained from the encoder 24 is supplied to the D/A converter 25 .

Further, in the field memory 21, in accordance with the write clock pulse PW, the digital audio signal DA is divided and written for each one field period, and the written digital audio signal DA for one field period is written. Each clock pulse P for reading
It is read out according to R. In such a case, the frequency 4·ft/3 of the read clock pulse PR is set to 4/3 times the frequency ft of the write clock pulse PW, so that the digital audio signal DA read from the field memory 21 It is assumed that the time axis is compressed at a time compression rate of 3/4 for each of one field period, and furthermore, the read clock pulse PR is set at time T1 and time T1.
2, each of the digital audio signals DA for one field period is time-base compressed at a time compression rate of 3/4 and obtained from the field memory 21. A digital segmented time-base compressed audio signal starting from time T1 and continuing for a period Ft·3/4 and a time period Ft·3 starting from time T2.
The digital segmented time-base compressed audio signals that continue for 0.4 times are sent out alternately and intermittently, and they are assumed to form the digital time-base compressed audio signal DA' as a whole. supplied to

In the D/A converter 23 , the digital time-base compressed luminance signal DY' is converted into an analog signal to obtain a time-base compressed luminance signal Y', which is supplied to the luminance signal recording processing section 27 . In the luminance signal recording processing unit 27, frequency modulation (FM) processing is performed based on the time axis compressed luminance signal Y', and based on the time axis compressed luminance signal Y', for example, the carrier frequency shift band is time axis compressed. A time-base compressed FM luminance signal Yf' is formed in which the leading edge of the synchronization signal of the luminance signal Y' has a frequency of 5.7 MHz and the white peak has a frequency of 7.7 MHz. Then, from the luminance signal recording processing section 27, the cut-off frequency is, for example, about 2 MH.
A time-base compressed FM luminance signal Yf' is obtained through a high-pass filter (HPF) 28 set to z, and is supplied to a signal synthesis section 29.

In the D/A converter 25, the digital time-base compressed carrier color signal DC' is converted into an analog signal to obtain a time-base compressed carrier color signal C', which is supplied to the color signal recording processor 30. In the color signal recording processing section 30, a low-pass conversion time-domain compressed color signal Cc' having a color subcarrier frequency of about 743 KHz is formed based on the time-domain compressed carrier color signal C', and Color signal recording processing section 3
0 through a bandpass filter (BPF) 31 to obtain a low-pass conversion time-base compressed color signal Cc', which is supplied to the signal synthesis section 29.

In the D/A converter 26 , the digital time-base compressed audio signal DA' is converted into an analog signal to obtain a time-base compressed audio signal AU', which is supplied to the audio signal recording processor 32 . In the audio signal recording processing section 32, FM processing is performed based on the time-domain compressed audio signal AU'. ±100~150
A time-domain compressed FM audio signal Af' having a frequency of approximately 1.5 MHz is formed, and a time-domain compressed FM audio signal Af' is obtained from the audio signal recording processing unit 32 through a BPF 33 whose passband center frequency is approximately 1.5 MHz. and is supplied to the signal combining section 29.

In the signal synthesis section 29, the time-domain compressed FM luminance signal Yf' from the HPF 28, the low frequency converted time-domain compressed color signal Cc' from the BPF 31, and the time-domain compressed FM audio signal Af' from the BPF 33 are processed. Frequency multiplexing is performed to form a composite recording signal Sm. As shown in A in FIG. 3, this composite recording signal Sm has a period F starting from time T1 of the time-axis compressed FM luminance signal Yf'.
one field period lasting for t·3/4, one field period starting from time T1 of the low-pass conversion time-base compressed color signal Cc′ and continuing for a period Ft·3/4;
One field period of the time-axis compressed FM audio signal Af' starting from time T1 and continuing for a period Ft·3/4 is frequency multiplexed and synthesized, starting from time T1 and continuing for a period Ft·3/4. One field period Sm(n), Sm(n+2), . field period, one field period starting from time T2 of the low-pass conversion time axis compressed color signal Cc′ and continuing for a period Ft·3/4;
And, one field period starting from time T2 and continuing for a period Ft 3/4 of the time-axis compressed FM audio signal Af' is frequency-multiplexed and synthesized to produce a period Ft 3/4 starting from time T2. 1 compressed time axis that lasts only
Field period Sm(n-1), Sm(n+1),・
...are said to be continuous alternately and intermittently,
It is supplied to the movable contact 34a of the switch 34.

The switch 34 closes the movable contact 3 in response to a recording/reproduction discrimination signal SD during a reproduction operation to be described later.
4a is maintained connected to the selection contact 34c which is set as an empty contact, but during the recording operation, its movable state is controlled by a switch control signal SW supplied from a control signal forming section 55 through the terminal 35, which will be described later. The connection state between the contact 34a and the selection contacts 34b, 34c, and 34d is controlled. As shown in B in FIG. 3, the switch control signal SW corresponds to one field period Sm(n), Sm(n+2),...
・A high level H is taken in the period corresponding to each of . Taking the low level L, two adjacent time-axis compressed field periods Sm(n-1) and Sm(n), Sm(n) in the composite recording signal Sm
and Sm(n+1), Sm(n+1) and Sm(n+2
), .
When W takes a high level H, the movable contact 34a is connected to the selection contact 34b connected to the recording amplification section 36, and when the switch control signal SW takes an intermediate level M, the movable contact 34a is set as an empty selection contact 34c. When the switch control signal SW takes a low level L, the movable contact 34a is connected to the selection contact 34d connected to the recording amplification section 37. As a result, from the selection contact 34b of the switch 34,
As shown in C in FIG.
a is derived and supplied to the rotary magnetic head 41 through the recording amplifier 36, and from the selection contact 34d of the switch 34, Sm for one field period compressed on the time axis as shown in D in FIG. (n-1),S
A second composite recording signal component Smb formed by intermittent series of signals m(n+1), . Further, when the switch control signal SW takes the intermediate level M and the movable contact 34a of the switch 34 is connected to the selection contact 34c, the rotating magnetic head 41 is
and 42 are not supplied with signals.

Each of the rotating magnetic heads 41 and 42 has a mutually different gap azimuth, and is attached to a rotating part of the tape guide cylinder 43.
It is disposed between the rotating part and the fixed part of the tape guide cylinder 43, rotates with the rotating part of the tape guide cylinder 43, and travels through the magnetic gap forming part on the outer circumferential surface of the tape guide cylinder 43. tape 45
The magnetic tape 45 is scanned in a direction forming a predetermined angle of intersection with the running direction of the magnetic tape 45. The rotating magnetic heads 41 and 42 are attached to the rotating part of the tape guide cylinder 43, as shown in FIG. It is meant to be.

The magnetic tape 45 is made to run by a capstan 47 which is rotationally driven by a capstan drive motor 46 and a pinch roller 48 which is in contact with the capstan 47 with the magnetic tape 45 sandwiched therebetween. It is controlled by the stun servo control circuit 49 to cause the magnetic tape 45 to take a predetermined running speed. In addition, the rotating magnetic heads 41 and 4
The rotating part of the tape guide cylinder 43 to which the tape guide cylinder 2 is attached is rotationally driven by a cylinder drive motor 50 in the direction indicated by the arrow XH in FIG. The rotating parts in the cylinder 43, and thus the rotating magnetic heads 41 and 42, are caused to have a predetermined rotation speed.

The diameter of the tape guide cylinder 43, the tape wrapping angle about the tape guide cylinder 43, and the cylinder rotation speed, that is, the rotation speed of the rotating magnetic heads 41 and 42, are as follows: a standard tape guide cylinder with a diameter of 40 mm. and two standard rotary magnetic heads, the tape winding angle for the standard tape guide cylinder is 180 degrees, and the cylinder rotation speed, that is, the rotation speed of the standard rotary magnetic head is approximately 29.97 rps. It is defined based on a standard video tape recorder, and the tape guide cylinder 4
3 is set to 2/3 of the diameter of the standard tape guide cylinder (40 mm), that is, approximately 26.67 mm, and the tape winding angle for the tape guide cylinder 43 is set to 2/3 of the diameter (40 mm) of the standard tape guide cylinder, and the tape winding angle for the tape guide cylinder 43 is the same as that for the standard tape guide cylinder. The rotation speed of the two rotating magnetic heads 41 and 42 is set to 3/2 of the angle (180 degrees), that is, 270 degrees, and the rotation speed of the two rotating magnetic heads 41 and 42 is twice the rotation speed of the standard rotating magnetic head (approximately 29.97 rps). That is, it is set to approximately 59.94 rps, and therefore, the period of one rotation of the rotating magnetic heads 41 and 42 is approximately 1/60 second, which approximately corresponds to the field period Ft.

The recording scanning state of each of the rotary magnetic heads 41 and 42 to form a recording track on the magnetic tape 45 is determined by the rotary magnetic head 4.
1, as shown in E in FIG. 3, during each period of every other rotation, one field period Sm( n), Sm(n+2), .
During each period of every other rotation, one field period Sm(n-1), Sm(n+1) of the second composite recording signal component Smb which is time-axis compressed is supplied.
), . Thereby, each time each of the rotating magnetic heads 41 and 42 alternately records and scans the magnetic tape 45, Sm(n), Sm( n+2
), . . . and the second composite recording signal component Sm
Sm(n−
1), Sm(n+1), . . .
5, recording is performed alternately with recording tracks formed at a constant angle of inclination with respect to the longitudinal direction of the recording tracks.

In this way, as shown in FIG.
On the magnetic tape 45, a recording track Ta is formed every other rotation of the rotating magnetic head 41, and a recording track Tb is formed every other rotation of the rotating magnetic head 42. The recording track Tb is arranged between each set of two adjacent recording tracks Ta, and the recording track Ta is recorded by the rotary magnetic head 41.
and recording tracks Tb by the rotating magnetic head 42 are alternately arranged in parallel. In such a case, the rotating magnetic head 41
Since the rotating magnetic head 42 and the rotating magnetic head 42 are designed to have a rotation angle interval of approximately 45 degrees, the magnetic tape 45 of the rotating magnetic heads 41 and 42 rotates in the direction shown by the arrow XH in FIG. (traversing in the direction indicated by arrow XT), first, scanning by the rotating magnetic head 41 is started, and then approximately 4
Scanning by the rotating magnetic head 42 is started after a delay of a time corresponding to a rotation angle interval of 5 degrees. Therefore, if the rotating magnetic head 41 and the rotating magnetic head 42 are arranged in a straight line in the scanning direction of the magnetic tape 45 without any difference in position (step) in the direction perpendicular to the scanning direction, then After the recording track Ta is formed by the recording scan by the rotary magnetic head 41 shown by the solid line in FIG. 4, the recording track Tb is formed by the recording scan by the rotary magnetic head 42 in the next one rotation period. 42 is at position 4 indicated by a dashed line in FIG.
2', the recording track Tb is not placed in the center between the two adjacent recording tracks Ta, and the recording track Ta and the recording track Tb are formed at equal intervals on the magnetic tape 45. It is treated as something that should not be done.

Therefore, in reality, as shown in FIG.
The rotating magnetic head 42 is connected to the rotating magnetic head 41,
It corresponds to the moving distance of the magnetic tape 45 in the direction perpendicular to the scanning direction by the rotating magnetic head 42 relative to that of the magnetic tape 45 within a time corresponding to the rotation angle interval of approximately 45 degrees in the direction perpendicular to the scanning direction with respect to the magnetic tape 45. Step S
It is assumed that a T is provided. By providing such a step ST, when the recording track Ta is formed by the recording scan by the rotary magnetic head 41 and the recording track Tb is formed by the recording scan by the rotary magnetic head 42, the rotary magnetic head 42 moves in the direction of the figure. 4, the position is closer to the rotating magnetic head 41 by the step ST than the position 42' shown by the solid line.
Two recording tracks T where recording tracks Tb are adjacent to each other
It shall be placed in the center between a.
Recording tracks Ta and Tb are formed on the magnetic tape 45 with a constant pitch PT.

With the settings as described above, the ratio of the diameter of the tape guide cylinder 43 to the diameter of the standard tape guide cylinder is AA, and the ratio of the tape guide cylinder 43 to the tape wrapping angle of the standard tape guide cylinder is AA.
BB is the ratio of the tape winding angle for , CC is the ratio of the rotational speed of the rotating magnetic heads 41 and 42 to the rotational speed of the standard rotating magnetic head, and EE is the time compression ratio of the composite recording signal Sm. For the example shown in FIG. 1 with magnetic heads 41 and 42, in order to provide compatibility with standard video tape recorders, the length of the recording track formed on magnetic tape 45 is longer than that of a standard video tape recorder. The length of the recording track formed on the magnetic tape by a standard video tape recorder is equal to the length of the recording track formed on the magnetic tape, and the period for one field period of the composite recording signal Sm recorded on the magnetic tape 45 is equal to the length of the recording track formed on the magnetic tape by a standard video tape recorder. The condition for the period to be equal to the period of one field period of the signal is as follows: AA・BB=1 (
a) BB/(CC·EE)=1 (b) The following two relationships hold true.

[0036] Then, looking at the respective values of AA, BB, CC and EE, AA=2/3, BB=3/2, CC=2
, EE=3/4, so the above equations (a) and (b
) is established. Therefore, the example shown in FIG. 1 employs a tape guide cylinder with a smaller diameter than that of a standard video tape recorder, and the number of rotating magnetic heads is reduced to two without increasing the number of rotating magnetic heads. A color television signal consisting of a video signal including a luminance signal and a carrier color signal and an audio signal can be recorded on a magnetic tape while maintaining compatibility with a standard video tape recorder. become.

The switch 34 connects its movable contact 34a to the selection contact 34c, and the signal synthesis section 29
As is clear from E and F in FIG. 3, the state in which signals are not supplied from the side to the rotary magnetic heads 41 and 42 starts from the time when the rotary magnetic head 42 finishes recording scan on the magnetic tape 45. 41 starts the next recording scan on the magnetic tape 45, a first non-recording period R1 in which both the rotating magnetic heads 41 and 42 are not in contact with the magnetic tape 45; A second non-recording period R2 is taken from the time when the recording scan on the magnetic tape 45 ends until the time when the rotary magnetic head 42 starts the next recording scan on the magnetic tape 45. Then, in the initial part of the second non-recording operation period R2, the rotating magnetic head 42
In this case, the step ST provided between the rotating magnetic head 41 and the rotating magnetic head 42 as described above is in contact with the magnetic tape 45 over a rotation angle of 45 degrees. is extremely small, so the rotating magnetic head 4
1 is the first composite recording signal component Sma on the magnetic tape 45.
Sm(n) for one field period compressed on the time axis,
The rotary magnetic head 42 scans the end portion of the recording track Ta formed by recording each of Sm(n+2), . A read output signal Sa from the recording track Ta is obtained.

At this time, since the rotating magnetic head 42 has a gap azimuth different from that of the rotating magnetic head 41, the read output signal Sa obtained from the rotating magnetic head 42 is different from the first one recorded on the recording track Ta. Time axis compressed one field period Sm in the composite recorded signal component Sma
(n), Sm(n+2), . Field period Sm(n), Sm(n+
2) The low frequency components in each of..., specifically,
It is assumed that the low frequency conversion time-domain compressed color signal Cc' and the time-domain compressed FM audio signal Af' are read. In addition, in such a case, the magnetic tape 45 by the rotating magnetic head 41
The formation of the recording track Ta for the rotary magnetic head 41 has been completed, and the first composite recording signal component Sma for the rotary magnetic head 41 has been completed.
Therefore, the read output signal Sa obtained from the rotating magnetic head 42 is not contaminated with crosstalk components of the signals supplied from the signal combining section 29 to the rotating magnetic heads 41 and 42.

An envelope detector 102 is connected to the rotating magnetic head 42 via a BPF 101, and the BP
F101 has a relatively low passing frequency band that allows the read output signal Sa obtained from the rotating magnetic head 42 to pass therethrough. Then, a second non-recording operation period R
2, the end portion of the recording track Ta formed by the rotary magnetic head 41 is
2 is in a scanning state, and the signal containing the read output signal Sa obtained from the rotating magnetic head 42 is
The signal is supplied to the envelope detection unit 102 through the BPF 101. A detection output signal SE having a level corresponding to the envelope of the signal including the read output signal Sa is obtained from the envelope detection section 102 and is supplied to the level comparison section 103.

In the level comparing section 103, the level of the detection output signal SE from the envelope detecting section 102 is compared with a predetermined constant level of the reference voltage Vr obtained from the reference voltage source 104. The level of the reference voltage Vr is
The read output signal Sa obtained from the rotating magnetic head 42 is
When the rotating magnetic head 41 is in an appropriate state where no clogging occurs in the magnetic gap forming portion, the magnetic tape 4 is
Sm(n), Sm(n+
2), . When the level of the detection output signal SE from the envelope detection unit 102 is lower than the level of the output signal SE, and when at least one of the rotating magnetic heads 41 and 42 is in a state where clogging has occurred in its magnetic gap forming portion, the level of the detection output signal SE from the envelope detection unit 102 Those that meet the above criteria have been selected. The level comparison unit 103 takes a high level when the level of the detection output signal SE from the envelope detection unit 102 is higher than the level of the reference voltage Vr,
A level comparison output SQ that takes a low level when the level of the detection output signal SE from the envelope detection section 102 is lower than the level of the reference voltage Vr is obtained, which is used as a delayed flip-flop (D) forming a latch circuit section. -F.
F. ) 105 is supplied to the D terminal.

On the other hand, the rotating portion of the tape guide cylinder 43 is provided with a magnetized portion 56, and the magnetized portion 56 is attached to the rotating magnetic heads 41 and 42 as the rotating portion of the tape guide cylinder 43 rotates. It is detected by a fixed magnetic head 57 which assumes a preset position while being rotated together. As a result, every time the magnetized portion 56 passes by, the fixed magnetic head 57 rises from the zero level to the positive level side, and then goes to the negative level side, for example, every time the rotating magnetic heads 41 and 42 rotate. A pulse signal PG that returns to zero level after falling is obtained. Then, the position of the magnetized portion 56 provided in the rotating part of the tape guide cylinder 43 is selected, and the pulse signal PG from the fixed magnetic head 57 is
In the initial part of the non-recording operation period R2, the rotating magnetic head 42 immediately after the preceding rotating magnetic head 41 of the rotating magnetic heads 41 and 42 in the rotating state finishes the recording scan on the magnetic tape 45. This occurs when the rotary magnetic head 41 is scanning the end portion of the recording track Ta formed on the magnetic tape 45, and therefore when the read output signal Sa is obtained from the rotary magnetic head 42. The waveform shaping section 58 converts the signal into a rectangular wave pulse PGW consisting of a pair of positive level portions and negative level portions, as shown by H in FIG. 3, and supplies the pulse to the control signal forming section 55.

In the control signal forming section 55, as shown by I in FIG. 3, the falling portion of the rectangular wave pulse PGW from the waveform shaping section 58 consists of a pair of positive level portion and negative level portion. A pulse signal CP is formed with a leading edge synchronized to the time of the central part of the square wave pulse PGW, which is connected to D-F. F. 105 clock (CK)
Supplied to the terminal. As a result, D-F. F. From the Q terminal of 105, the level of the level comparison output SQ at the time of the leading edge of the pulse signal CP, and therefore the level of the rotating magnetic head 4
An output signal SCG having the level of the level comparison output SQ based on the read output signal Sa obtained from 2 is obtained,
It is led out to the detection output terminal 106.

The output signal SCG obtained at the detection output terminal 106 in this way is the read output signal Sa obtained from the rotating magnetic head 42 when clogging occurs in the magnetic gap forming portion of both the rotating magnetic heads 41 and 42. The read output signal Sa obtained from the rotating magnetic head 42 takes a high level when the read output signal Sa is obtained under an appropriate state in which the magnetic gap is not formed. A low level is assumed when the signal is obtained under conditions where clogging occurs in the area. Therefore, the output signal SCG
When taking a high level, the rotating magnetic heads 41 and 42
Indicates that no clogging has occurred in the magnetic gap forming portion, and when the level is low, at least one of the rotating magnetic heads 41 and 42 indicates that clogging has not occurred in the magnetic gap forming portion. Based on this output signal SCG, one field period Sm(n), Sm compressed on the time axis in the first composite recording signal component Sma for the magnetic tape 45 is generated. (n+2),...
- Clogging in the magnetic gap forming portion of the rotating magnetic head 41 during the recording operation for recording each of the above, and further, the rotating magnetic head 4 reading the recording signal from the recording track formed by the rotating magnetic head 41.
Accurate detection of clogging in the magnetic gap forming portion for 2 is performed.

Note that the control signal forming section 55 forms a switch control signal SW, which is supplied to the switch 34 through the terminal 35, based on the rectangular wave pulse PGW from the waveform shaping section 58.

Furthermore, the rotating magnetic heads 41 and 42 include:
Reproduction systems are connected through connection points Z1 and Z2, respectively, and such reproduction systems are shown in FIG.

The reproduction system shown in FIG. 6 uses the example of the magnetic tape recording device shown in FIG. This constitutes an example of a signal reproducing device for reproducing color signals and audio signals, and in this example, a rotary magnetic head for reading is used as shown in FIG.
The two rotating magnetic heads 41 and 42 in the example of the magnetic tape recording device shown in FIG. Furthermore, the capstan 47 and the capstan servo control circuit 49, a fixed magnetic head 57 that detects the magnetized portion 56 provided on the tape guide cylinder 43, and a waveform shaping section 58 to which the pulse signal PG from the fixed magnetic head 57 is supplied. , and the rectangular wave pulse P from the waveform shaping section 58
The control signal forming unit 55 to which GW is supplied is also used.

In the reproducing system shown in FIG. 6, two rotating magnetic heads 41 and 42 having mutually different gap azimuths and arranged with a rotation angle interval of about 45 degrees are used. It is rotated in the direction indicated by arrow XH at a rotation speed of 94 rps, and
In the normal reproduction operation mode, the magnetic tape 45 is made to run at the same speed as during the recording operation, that is, at the reference speed, and the rotating magnetic heads 41 and 42 move the magnetic tape 45 forward.
A state is taken in which the state is scanned. At this time, since the two rotating magnetic heads 41 and 42 are arranged with a step ST between them, the recording tracks Ta and Tb, which are alternately arranged in parallel with equal pitches on the magnetic tape 45, Each rotation of the two rotating magnetic heads 41 and 42, the rotating magnetic head 41 scans the magnetic tape 45 along the recording track Ta, and the rotating magnetic head 41 scans the magnetic tape 45 along the recording track Ta. A state in which each of Sm(n), Sm(n+2), . Truck T
The magnetic tape 45 is scanned along the recording track T
Sm (n-1), Sm for one field period compressed in the time axis in the second composite recording signal component Smb recorded in b
(n+1), . . . are read alternately.

As a result, the rotating magnetic head 41 is rotated as shown in FIG.
The magnetic tape 45 is scanned in the period during each rotation indicated by diagonal lines in A in FIG. Sm(n), S for one field period compressed on the time axis in the composite recording signal component Sma of
m(n+2), . During scanning, the second composite recording signal component S is generated in a manner as shown in D in FIG.
Sm(n
-1), Sm(n+1), . . . are respectively sent out as read output signals.

The first composite recording signal component Sma sent out from the rotary magnetic head 41 is time-base compressed for one field period Sm(n), Sm(n+2), . . .
The time axis of the second composite recording signal component Smb sent out from the rotating magnetic head 42 is compressed for one field period Sm.
(n-1), Sm(n+1), . The switch 63 is
During the recording operation, the movable contact 63a is maintained connected to the vacant selection contact 63c by the recording/reproduction discrimination signal SD. The connection state between the movable contact 63a and each of the selection contacts 63b and 63d is controlled by the switch control signal SW' supplied through the switch control signal SW'. As shown in E in FIG. 7, the switch control signal SW' alternately takes a low level L and a high level H for each period including each tape scanning period of the rotary magnetic heads 41 and 42. One field period Sm(n), Sm(
n+2),...low level L during the period including each of
, and one field period Sm(n-1), Sm(n+
1), etc., and when the switch control signal SW' takes a low level L, the movable contact 63a is connected to the selection contact 63b, and the switch control signal SW' When is at a high level H, the movable contact 63a is connected to the selection contact 63d. As a result, the first composite recording signal component Sma obtained alternately from the reproduction amplification units 61 and 62 is obtained by compressing the time axis of one field period, and the second composite recording signal component Smb is compressed in the time axis by one field period. Each of the field periods forms a series of composite recording signals Sm as shown at F in FIG. 7, and is derived from the movable contact 63a of the switch 63.

The composite recording signal Sm obtained from the movable contact 63a of the switch 63 is composed of the time axis compressed FM included therein.
HP corresponding to the luminance signal Yf', the low-frequency conversion time-axis compressed color signal Cc', and the time-axis compressed FM audio signal Af', respectively.
It is supplied to F71, BPF72 and BPF73. Then, the time axis compression F in the composite recording signal Sm is sent from the HPF 71.
The M luminance signal Yf' is obtained and supplied to the luminance signal reproduction processing section 74. In the luminance signal reproduction processing section 74, various processes including demodulation processing are performed on the time-axis compressed FM luminance signal Yf'. Luminance signal Y
' is obtained and supplied to the A/D converter 75. A/D
In the converter 75, the time-domain compressed luminance signal Y' is digitized to obtain a digital time-domain compressed luminance signal DY', which is supplied to the field memory 76.

[0051] Furthermore, a low frequency converted time axis compressed color signal Cc' in the composite recording signal Sm is obtained from the BPF 72 and is supplied to the color signal reproduction processing section 77. In the color signal reproduction processing section 77, various processes including frequency conversion processing are performed on the low frequency conversion time axis compressed color signal Cc'. The time axis compressed carrier color signal C' based on
8. In the A/D converter 78, the time-base compressed carrier color signal C' is digitized to obtain a digital time-base compressed carrier color signal DC', which is sent to the decoder 7.
9. In the decoder 79, a digital time axis compressed red color difference signal DR' which is formed by intermittently connecting digital time axis compressed color difference signals from the digital time axis compressed carrier color signal DC' and a digital time axis compressed red color difference signal DR' which is made up of an intermittent series of digital time axis compressed color difference signals and a digital time axis compressed color difference signal DR' which is made up of an intermittent series of digital time axis compressed color difference signals A series of digital time-base compressed blue color difference signals DB' are individually extracted and sent to a decoder 79.
Digital time-base compressed red color difference signal DR' obtained from
, and digital time-base compressed blue color difference signal DB' are supplied to field memory 80 and field memory 81, respectively.

Furthermore, the composite recording signal Sm from the BPF 73
The time-base compressed FM audio signal Af' is obtained and supplied to the audio signal reproduction processing section 82. Audio signal reproduction processing section 82
, various processes including demodulation processing are performed on the time-domain compressed FM audio signal Af', and a time-domain compressed audio signal AU' based on the time-domain compressed FM audio signal Af' is obtained from the audio signal reproduction processing section 82. and is supplied to the A/D converter 83. In the A/D converter 83, the time axis compressed audio signal AU' is digitized to obtain a digital time axis compressed audio signal DA', which is stored in the field memory 8.
4.

Field memories 76, 80, 81 and 8
A write clock pulse QW and a read clock pulse QR sent from the timing pulse generator 85 are supplied to each of the clock pulses 4 and 4. The timing pulse generator 85 is supplied with a synchronizing pulse Pv' synchronized with the level change portion of the switch control signal SW' through a terminal 85A, and the timing pulse generator 85 receives a write clock pulse QW.
has a frequency of 4·ft/3, and each field period of the digital time-base compressed luminance signal DY' sent from the A/D converter 75 is stored in the field memory 76 based on the timing of the synchronizing pulse Pv'. The clock pulse Q for reading is sent out intermittently every period supplied to
R is continuously transmitted as having a frequency ft.

Thereby, in the field memory 76, the digital time-base compressed luminance signal DY' is divided and written for each field period according to the write clock pulse QW, and the written digital time-base compressed luminance signal DY' Each field period of signal DY' is
It is read out according to the read clock pulse QR. At this time, since the frequency ft of the read clock pulse QR is set to 3/4 times the frequency 4·ft/3 of the write clock pulse QW, the field memory 76 outputs the written digital time axis compressed luminance. The time axis of each field period of the signal DY' is expanded at an expansion rate of 4/3, and is sequentially and continuously sent out, and is supplied to the D/A converter 86 as a signal that forms the digital luminance signal DY as a whole. be done.

In the D/A converter 86, the digital luminance signal DY is converted into an analog signal to obtain a luminance signal Y.
It is reproduced as the luminance signal Y at the video signal output terminal 8.
7.

Furthermore, in the field memory 80,
According to the write clock pulse QW, each field period of the digital time-base compressed red color difference signal DR' is sequentially written, and each field period of the written digital time-base compressed red color difference signal DR' is written as the read clock pulse. At the same time, each field period of the digital time-base compressed blue color difference signal DB' is sequentially read in the field memory 81 according to the write clock pulse QW, and the written digital time-base compressed blue color difference signal DB' is sequentially read out according to the QR. Blue color difference signal D
Each field period of B' is the read clock pulse QR.
are read out sequentially according to In such a case, the frequency ft of the read clock pulse QR is equal to the write clock pulse Q.
Since it is said to be 3/4 times the frequency of W, 4·ft/3,
From the field memory 80, the time axis of each field period of the written digital time-base compressed red color difference signal DR' is expanded at an expansion rate of 4/3 and is continuously sent out. DR is obtained, and each field period of the written digital time-axis compressed blue color difference signal DB' is continuously transmitted from the field memory 81 with its time axis expanded at an expansion rate of 4/3. A digital blue color difference signal DB is obtained. Both the digital red color difference signal DR and the digital blue color difference signal DB are supplied to the encoder 88, and in the encoder 88,
Both the digital red color difference signal DR and the digital blue color difference signal DB are combined to form a digital carrier color signal DC, and the digital carrier color signal DC obtained from the encoder 88 is supplied to the D/A converter 89.

In the D/A converter 89, the digital carrier color signal DC is converted into an analog carrier color signal to obtain a carrier color signal C, which is outputted to the video signal output terminal 90 as a reproduced carrier color signal C.

Further, in the field memory 84, the digital time-base compressed audio signal DA' is divided and written for each one field period according to the write clock pulse QW, and the written digital time-base compressed audio signal DA' is written in accordance with the write clock pulse QW. Each of the signal DA' for one field period is read out in accordance with the read clock pulse QR. In such a case, the frequency f of the reading clock pulse QR
Since t is 3/4 times the frequency 4·ft/3 of the writing clock pulse QW, the written digital time-base compressed audio signal DA' is output from the field memory 84.
The time axis of each field period for one field period is expanded at an expansion rate of 4/3 and is sent out continuously, and these as a whole form a digital audio signal DA.
/A converter 91.

Then, in the D/A converter 91, the digital audio signal DA is converted into an analog audio signal AU.
is obtained and output to the audio signal output terminal 92 as a reproduced audio signal AU.

In this manner, the reproduction system shown in FIG. 6 reproduces the luminance signal Y, the carrier color signal C, and the audio signal AU forming the video signal from the magnetic tape 45 under the normal reproduction operation mode. Although a tape guide cylinder 43 having a diameter smaller than that of a standard tape guide cylinder is employed, it is sufficient to provide only two rotary magnetic heads 41 and 42 as regards the rotary magnetic head.

In the example of the magnetic tape recording device shown in FIG. 1, two rotating magnetic heads 41 and 42 are arranged such that the rotation angle interval between them is 45 degrees. The arrangement of the two rotating magnetic heads 41 and 42 is not limited to this example, and the rotational angular interval between them may be smaller or larger than 45 degrees. At that time, field memory 15,1
Digital luminance signal DY, digital red color difference signal DR, digital blue color difference signal DB from 8, 19 and 21
, and the reading period during each of the first and second field periods forming each frame period of the luminance signal Y for each of the digital audio signals DA corresponds to the rotation angle between the rotating magnetic heads 41 and 42. Although it changes depending on the interval, when both the rotary magnetic heads 41 and 42 are set to perform recording on the magnetic tape 45 at the same time, the field memories 15, 18, 19, and 2
In order to avoid such a situation, the circuit configuration including the rotating magnetic head 41 and its peripheral parts becomes extremely complicated and requires a special memory element, etc.
and 42 is smaller than the angle obtained by subtracting the tape wrapping angle from 360 degrees, and therefore, for example, is preferably set to be smaller than 90 degrees, which is 360 degrees minus the tape wrapping angle of 270 degrees. .

[0062]

As is clear from the above description, in the magnetic tape recording apparatus according to the present invention, for example, the unit segment signal component formed based on the signal to be recorded, which is a video signal, is intermittently transmitted. A series of recording signals are simultaneously rotated at rotational angular intervals set at, for example, 45 degrees, and run along the outer circumferential surface portion of the tape guide cylinder during each rotation period. Recording is performed on the magnetic tape by first and second rotating magnetic heads that scan the magnetic tape. The second rotating magnetic head is rotated to follow the rotation angle at a set rotation angle interval, and the first
and the second rotating magnetic head, for each rotation thereof,
Each of the unit segment signal components forming a recording signal is alternately supplied, and each of the unit segment signal components is applied to a recording track on the magnetic tape by the first or second rotating magnetic head to which the unit segment signal component is supplied. are formed and recorded sequentially. During the rotation period of the first and second rotary magnetic heads during which a recording track is formed on the magnetic tape by the preceding first rotary magnetic head, the first rotary magnetic head records a recording track on the magnetic tape. After the recording track is formed, the second rotating magnetic head that follows the first
A read output signal obtained from the second rotating magnetic head is detected by partially scanning the recording track formed by the rotating magnetic head, and based on the detected output signal obtained as a result, the first and second Since a clogging detection signal corresponding to the clogging of the rotating magnetic head is formed, based on the clogging detection signal, the magnetic clogging detection signal of the first rotating magnetic head during a recording operation of recording a recording signal on the magnetic tape is generated. It is possible to accurately detect clogging in the gap forming portion, and furthermore, clogging in the magnetic gap forming portion of the second rotating magnetic head that reads recording signals from the recording track formed by the first rotating magnetic head. It will be possible.

[Brief explanation of drawings]

FIG. 1 is a block connection diagram showing an example of a magnetic tape recording device according to the present invention.

FIG. 2 is a time chart used to explain the operation of the example shown in FIG. 1;

FIG. 3 is a time chart used to explain the operation of the example shown in FIG. 1;

FIG. 4 is a conceptual diagram used to explain the operation of the example shown in FIG. 1;

FIG. 5 is a conceptual diagram for explaining the arrangement of the rotating magnetic head in the example shown in FIG. 1;

6 is a block connection diagram showing a reproducing system constituting an example of a signal reproducing device for reproducing signals from a magnetic tape on which signals have been recorded according to the example shown in FIG. 1; FIG.

FIG. 7 is a time chart used to explain the operation of the reproduction system shown in FIG. 6;

[Explanation of symbols] 15 Field memory 18 Field memory 19 Field memory 21 Field memory 22 Timing pulse generation section 27 Luminance signal recording processing section 29 Signal synthesis section 30 Color signal recording processing section 32 Audio signal recording processing section 36 Recording amplification section 37 Recording amplification section 41 Rotating magnetic head 42 Rotating magnetic head 43 Tape guide cylinder 45 Magnetic tape 55 Control signal forming section 57 Fixed magnetic head 58 Waveform shaping section 101　BPF 102 Envelope detection section 103 Level comparison section 104 Reference voltage source 105　D-F. F. 106 Detection output terminal

Claims (1)

[Claims] 1. A recording signal forming section that forms a recording signal consisting of an intermittently series of unit segment signal components based on a signal to be recorded; first and second rotating magnetic heads that are rotated and scan a magnetic tape running along an outer peripheral surface portion of a tape guide cylinder during each rotation period; and each rotation of the first and second rotating magnetic heads; unit segment signal components in the recording signal obtained from the recording signal forming section are sequentially and alternately supplied to the first and second rotating magnetic heads, and the unit segment signal components are supplied onto the magnetic tape. a recording signal supply unit that causes a recording track to be formed by the first or second rotating magnetic head, and a recording track is formed on the magnetic tape by the first rotating magnetic head. During the rotation period of the first and second rotary magnetic heads, after the recording track is formed on the magnetic tape by the first rotary magnetic head, the recording is obtained from the second rotary magnetic head. a read output detection unit that detects a read output signal from the track; and a clogging unit that forms a signal corresponding to clogging for the first and second rotating magnetic heads based on the detection output signal obtained from the read output detection unit. A magnetic tape recording device comprising: a detection signal forming section;