JPS5987643A - Recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an apparatus for recording, for example, a video signal or an audio signal by a unit time as diagonal tracks on a tape by a rotating head, and reproducing the recorded tracks. In particular, it relates to a tracking control method during playback.

BACKGROUND TECHNOLOGY AND PROBLEMS In a device that records video and audio signals on a magnetic tape by forming one diagonal track for each unit time using a helical scan type rotary head device, and plays back the same, Tracking control, which ensures that the rotating head correctly scans the recording trunk during playback, uses a fixed magnetic head to send a control signal recorded at one end of the tape in the width direction to the fixed head during recording. This is done by reproducing the information so that the reproduction control signal and the rotational phase of the rotary head have a constant phase relationship.

However, this method has the disadvantage that a fixed magnetic head must be provided especially for tracking control.

OBJECTS OF THE INVENTION It is an object of the present invention to make it possible to easily control the tracking of a rotary head for reproduction by utilizing the output of the rotary head without using a fixed head for tracking control.

SUMMARY OF THE INVENTION The present invention provides a recording and reproducing apparatus having a helical scan type rotary gutter device, in which a pyro gutter signal is recorded in a diagonal track approximately in the center of the rotating head in the scanning direction in a state that can be separated from the signal to be recorded. A recording/reproducing device in which a pilot signal is recorded and the pilot signal is used as a tracking control signal for a rotating head during reproduction, and the tape is wound around the tape guide drum regardless of the shape of the corners. Also, tracking control can be performed well even during variable speed playback.

Embodiment Hereinafter, an example of the device of this invention will be described.
Let's explain the case of a new device for recording and reproducing data by converting it into an image with reference to the drawings.

This uses a plurality of rotating heads. For example, in the case of two rotating heads, a rotating head device as shown in FIG. 1 is used.

The rotating magnetic heads (IA) and (IB) are arranged at equal angular intervals, that is, at an angular interval of 180°. On the other hand, the magnetic tape (2) is placed on the circumferential surface of the tape guide drum (3).
It is wound over a narrower angular range, for example 90°. Then, the rotating head (IA) and (I B
) is rotated in the direction of the arrow (5H) at a rate of 30 revolutions per second, and the tape (2) is run at a predetermined speed in the direction of the arrow (5T).
and (IB), one diagonal magnetic track (4A) (4B) is formed on the magnetic tape (2) as shown in FIG.
> is formed in a so-called overwritten state, and the PCM
The signal is made to be recorded. That is, the head (I
A) The gap width (head track width) of (IB) is made larger than the track pitch.

In this case, the width directions of the gears of the heads (LA) and (IB) are set in different directions with respect to the direction orthogonal to the scanning direction. In other words, the so-called azimuth angles are made different.

According to the above rotary head device, two rotary heads (L
A) The period during which (IB) are not abutted together against the tape (2) (this is the period of the 90° angular range bone in this example)
If this period is used to add redundant data during recording and perform correction processing during playback, the apparatus can be simplified.

In this case, a control signal for tracking is recorded in the center portion of each trunk (4A) (4B), as indicated by the diagonally shaded ζ box in FIG. Here, the control signals include pilot signals P1 and R3 of frequencies f1 and 13 alternately for the trunk (4A), and pilot signals of frequencies f2 and f for the truck (4B).
Pyroso Bit No. 4 P2 and P→ are recorded alternately. Note that in this example, the audio PCM signal is based on this pilot signal P1. P2+ R3゜R4
This pilot signal P1. P
2. P3. It is time-compressed and recorded in a portion other than the recorded portion of P4.

FIG. 3 shows an example of the recording system.

This example is an example in which an audio signal is recorded as a two-channel signal of left and right channels.

In Figure 3, the left and right channel audio signals S
L and 31. are input terminals (IIL”) and (IIR)
The switch circuit (12) receives a switching signal SW of, for example, 44.1kllZ from the control signal generation circuit (13) (Fig. 4A).
), the signal needle is alternately switched between a high level period and a low level period.

Therefore, the left channel signal SL and the right channel signal SR are alternately taken out from this switch circuit (12) and supplied to the D/D converter (14).

In the A/D converter (14), each channel is sampled at a sampling frequency of 44.1 kHz, and the sampled signal is converted into a PCM signal of, for example, 16 bits per sample. FIG. 4B shows the output signal So of this A/D converter (14),
LOI L1+L2 . . . indicates the data word of the audio PCM signal of the left channel, and Ro, R1, R2 . . . indicate the data word of the audio PCM signal of the right channel.

The output So of the A/D converter (14) is supplied to the recording encoder (15). This recording encoder (15) has two memory circuits such as RAM (16) (17).
), parity word and CRC code addition circuit (1
8) is connected. And this recording encoder (
In 15), the control signal generation circuit (13)
The two RAMs (16) and (17) are switched every - second (corresponding to the time of half a revolution of head 0 (LA>(IB>)) by the control signal R3W (Fig. 4E) from the signal So. is the 735 data words L of the left channel for each minute of that one-second period.

~L734 and 735 data words R of the right channel
For every total of 1470 data words with o=Rv3+,
The two RAll (16) (17) are written as shown in FIG. 4C and D. In other words, during the period TB in which the signal RSH is at a high level in the first half of one cycle, the RAM
(16).

A data word is written into the RAM (17) during the second half period T^ when the level is low.

Then, the data written in the RAM (16) in the period TB is stored in the period T^ and in the RA in the period T^.
The data written in M (17) is read out in period TB with parity words P, Q and a CRC code added thereto.

That is, 6 from the control signal generation circuit (13)
The signal CP of 011z (FIG. 4F) is the parity and CRC
The code is supplied to the code generation/addition circuit (18), and each period T^
During the first half of the periods TAP and T@p, the signal CP becomes high level and the generation/addition circuit (18) is brought into operation.

Therefore, in the first half of the period TAP, the generation/addition circuit (18) writes the parity word P to the data written in the RAM (16).

Q and CRC codes are formed and appended to the data and written back to RAM (16).

Then, in the period TAR in the second half of this period T^, the data to which the parity words P, Q and CRC code are added is read out at approximately twice the writing speed.

Similarly, in the period TIIP in the first half of the period Tn, RAM (1
Parity words P, Q and a CRC code are formed in the circuit (18) for the data written in the RAM 7) and added to the data.
(17) is written again. Then °ζ, this period TR
During the second half of period TBFI, the data to which the parity words P, Q and CRC code are added is read out at approximately twice the writing speed.

In this way, the data obtained by the recording encoder (15) for each unit time is supplied to the rotary heads (IA) (IB) via the recording amplifier (19) and recorded on each trunk. However, in this example, a tracking pilot signal is recorded in the center of each track without overlapping with audio data.

For this reason, the recording encoder (15) and recording amplifier (19)
) A switch circuit (20) is provided between the two. Then, this switch circuit (20) is reversed from the state shown in the figure for a certain time τ in the center of each readout period T An , T ey+ by the control signal Dsv (FIG. 4G) from the control signal generation circuit (13). is switched to the state ζ
, a pilot signal from a pilot signal generation circuit (21) is supplied to the rotary heads (IA) and (IB) through a recording amplifier (19). In this case, the scanning period T of the rotary head (IA) to form the track (4A) is
The pilot signals inserted into AB are a first pilot signal P1 having a single frequency 11 and a first pilot signal P1 having a single frequency 13.
The pilot signal inserted into the scanning period T8R of the rotary head (IB) to form the trunk (4B) is the second pilot signal of a single frequency f2. P2 and a fourth pilot signal P4 of a single frequency f4 alternate.

be made to become. Control for this purpose is performed every time signals R5W, cp, etc. from the control signal generation circuit (13) are supplied to the pilot signal generation circuit (21).

Here, frequencies fz, f2. ri and fi are different from each other, and are selected to be low frequencies at which attenuation due to azimuth loss due to differences in head azimuth angles is relatively small, but not so low that it is difficult to erase. In other words, if the frequency is too high, tracking control during playback (described later) will not be possible due to azimuth loss; on the other hand, if the frequency is too low, new information will be recorded over previously recorded tape that is no longer needed. This is because when so-called override is performed, in which the previous recording is erased, the low frequency signal portion remains without being erased.

For example, these frequencies ft+ f2+ f3+
'4 is a value between 100 kHz and 500 kHz.

This pilot signal P1. P2. P3. During the period τ during which P4 is inserted, ζ is RAM (16) (17)
Reading of data from is stopped. Then, as is clear from FIG. 4 [I and I], the audio data every 7 seconds is time-compressed into the periods T AR and T IIR excluding the period τ.

In this way, the predetermined pilot signal is inserted from the switch circuit (20) for the period τ, and the period T AB ,
Read data (H and ■ in FIG. 4) is obtained at TBR. Then, as shown in Figure 2, the rotating head (
PCM with pilot signal P1 inserted by IA)
The data is tracked (4At) and the pilot signal P
PCM data with 3 inserted is recorded as track (4A3) and °C1 respectively, and PCM data with pilot signal P2 inserted by the rotary head (IB) is recorded as track (4B2) with pilot signal P4 inserted. PCM data is recorded as tracks (4B4).

In this case, as shown on the right side of FIG. 4B, the audio data every - second is made up of 1470 data words divided into blocks of 6 data words.
1470+6 = 245 blocks BO* Bl
+B2,...B244. And this one
In addition to these six data words, each block has parity words P, Q and a CRC code added to it, as well as a block synchronization signal 5VNC and a block address signal ADS.
It is constructed by adding 1. Note that the 6 data words, which constitute 1 block, are interleaved within the range of the bone data for a unit period of -6 seconds to strengthen against burst errors. Furthermore, a preamble signal used to generate a clock for data extraction during playback and a postamble signal indicating the end of the unit period bone data are added to this unit period bone data.

In this case, the heads (IA) and (IB) are subjected to phase servo so as to be synchronized with the reference pulse CT of 3011z from the control signal generation circuit (13), and the period T
In AR, the head (CIA) exactly scans the tape (2), and for a period of '1'', in the BR, the head (IB) scans the tape (2).
It is designed to scan exactly above. The pulse CT is supplied to the servo circuit (22), while the 3011z pulse PG from the pulse generator (23), which generates one pulse every 11 rotations of the head (LA) (IB), is supplied to the servo circuit (22). The output is supplied to a circuit (22), and its output is supplied to a head driving drum motor (24), where phase servo is applied.

Also, (25) is a capstan, and (26) is a pinch roller, and the tape (2) is transported by these, but the capstan is servoed so that it rotates correctly at a constant speed during recording. . That is, (27) is a capstan drive motor, and a frequency generator (28) is provided coaxially with its rotating shaft. This frequency generator (
A frequency signal corresponding to the rotational speed of the motor (27) from 28) is supplied to a speed servo circuit (29), the output of which is fed back to the motor (27) via an adder circuit (30).

As a result, the output frequency of the frequency generator (28) is set to a predetermined value, that is, the rotational speed of the motor (27) is set to a predetermined value. In this example, more precise rotation is taken into consideration, and the frequency signal is supplied to the phase comparison circuit (31), while the reference signal from the control signal generation circuit (13) is supplied to this circuit. The signal is supplied to a phase comparator circuit (31), and their phase error outputs are supplied to an adder circuit (30) so that the phase difference is also in a constant relationship with the reference signal.

In addition, during the first 120 seconds of each period T^ and TB, the head (IA) and (IB) are transmitted through the recording amplifier (19).
Data is supplied from RAMs (17) and (18) to the tape (17) and (18), but since both the heads (IA) and (IB) are in contact with the tape (2) during this period and are not in contact with the tape (2), some copies are not recorded. During this period, only the generation and addition of parity and CRC codes are performed in the circuit (18).

The audio signal recorded as a PCM signal is reproduced as follows.

That is, in the reproduction system shown in FIG.
2), and its output is supplied to the drum motor (24) to control the rotational phase of the rotation heads (IA) and (IB) to have a constant phase relationship with respect to the reference signal RBP. Therefore, if the control signal generating circuit (32) obtains a signal for controlling subsequent control timing based on the reference signal REF, good timing control can be achieved.

Now, a description will be given assuming that tracking control is performed as described later, and the head (IA) correctly scans the track (4A), and the head (IB) correctly scans the track (4B).

The playback outputs of the heads (IA) and (IB) (see Figure 6 A and B) are supplied to the ζ switch circuit (34) through amplifiers (33A) and (33B), respectively, and this switch circuit (34) By the 30 flz signal 511 (FIG. 6C) from the control signal generation circuit (32), ζ is alternately switched to one input terminal and the other input terminal, and from this, the playback output of the heads (IA) and (IB) is A signal with alternating states is obtained.

The output of this switch circuit II (34) is supplied to a digital signal restoration circuit (35) and restored to a digital signal, which is then supplied to a decoder (36) to restore the original PCM signal S.
o.

That is, in the decoder (36), the control signal R5Wp (sixth
Figure J) allows two RAMs (37) and (38
) is switched in the period Tc and 'ro of box seconds, and the sixth
As shown in Figures H and ■, the first half of period Tc! During the 120 second period, the digital data excluding the pilot signal from the reproduced output of one truck from the IA is written into the RAM (37), and the period T continues.

In the first half of the period of □ seconds, digital data excluding the pilot signal out of the reproduction output for one track from the head (IB) is written to the RAM (3B).

The data for the ■ track written in these RAMs (37) and (38) are respectively supplied to the period Tc and the control signal -C (sixth When the signal (K) in FIG. 1 becomes high level, this correction circuit (39) is enabled to operate, and errors are corrected within the range of its correction capability using parity P, Q and CRC codes.

In this way, the reproduced data for each trunk that has been written to the RAMs (37) and (38) and subjected to error correction is read out alternately at intervals of 1 mm, as shown in FIG. 6 H and I. . In other words, P extended to the original time axis
A continuous CM signal is obtained.

In this decoder (36), de-interleaving is also performed without returning the arrangement of data words to the original state of the PCM signal So.

The PCM signal from the decoder (36) is corrected in the error correction circuit (40) for data that could not be corrected in the correction circuit (39), and the data that could not be corrected by the correction circuit (39) is corrected.
1) and is returned to left, right, and 2-channel audio signals. Then °ζ, this is the switch circuit (42)
This switch circuit (42) is alternately switched by a switching signal similar to the switching signal S- during recording from the control signal generating circuit (32), and the 'r amplifiers (43L) and (43R) are respectively through the ゛ζ output end (
44L) and (44R), the left channel and right channel audio signals are demodulated and "ζ" is obtained.

Next, the track (4A) of the rotating head (IA) (IB)
Tracking control for (4B) will be explained.

First, the principle of tracking control in this case will be explained.

As mentioned above, since the gap width of the heads (IA) (IB) is larger than the track pitch, each head (IA) (IB) scans across adjacent tracks during reproduction. However, since adjacent tracks are recorded using different heads with different azimuths, the influence of crosstalk from adjacent tracks due to azimuth loss can be almost ignored for PCM audio data with a high recording bit rate. . On the other hand, pilot signal P1. P2. P3. P4 frequency fl+f2°f3
．． Since f4 is a low frequency as described above, it is not attenuated much by azimuth loss and is reproduced from adjacent tracks as well. Therefore, tracking control is possible by monitoring the pilot signal outputs of the tracks on both sides of the track to be scanned.

That is, for example, if the head (IA) scans the trunk (4A) in the state shown by the dashed line in Fig. 2, tracking is achieved.In this case, as is clear from the figure, the pilot signal P1 is Also when scanning the inserted track (4A1), the pilot signal P3
When scanning the track (4A3) in which is inserted, the pilot signals of the adjacent tracks are P2 and P4.

Therefore, if the levels of both image powers are made equal at the time when the reproduced outputs of both pilot signals P2 and P4 are obtained at the same time, the head (LA) just tracks the trunk (4A) that should be scanned. The head (IA) can be controlled to be brought to this just tracking position by changing the transport speed of the tape (2) in accordance with the difference between the two image forces. However, in this case, the left and right positions of the pilot signals P2 and P4 appearing in the trunk (4Ax) and (4A3) are swapped, so
The displacement direction by controlling the tape transport speed is set on both tracks (4
Az) and (4A3) must be completely reversed.

The same applies when the head (IB) scans the track (4B), and tracking can be achieved by controlling the tape transport so that there is no difference in level between the pilot signals P1 and P3 reproduced from adjacent tracks. In this case as well, the control directions for tracks (4B2) and (4B4) are reversed, as in the case of tracks (4A1) and (4A3).

The above tracking control is realized as follows.

That is, the reproduced signal from the switch circuit (34) is passed through four band pass filters (51) (52) (53).
) (54). These bandpass filters (
51) to (54) each have a passing frequency fx.

f2. E3. f4, the filter (51) is for detecting the first pilot signal P1, the filter (52) is for detecting the second pilot signal P2, and the filter (53) is for detecting the third pilot signal P1.
The filter (54) is for detecting the fourth pilot signal P4. Then, the output of the filter (51) (see Figure 6) and the output of the filter (51)
3) (see Fig. 6F) is supplied to the comparison differential amplifier (55), and the output of the filter (52) (see Fig. 6E) and the output of the filter (54) (see Fig. 6E) are supplied to the comparison differential amplifier (55). (see Figure G) is supplied to a comparison differential amplifier (56). The output of the differential amplifier (55) is a tracking control signal for the track (4B), and the output of the differential amplifier (56) is a tracking control signal for the track (4A).

As mentioned above, the output of the differential amplifier (55) depends on whether the tracking control is for the trunk (4B2) or (4B4), and the output of the differential amplifier (56) depends on whether the tracking control is for the trunk (4B2) or (4B4). ) polarity needs to be reversed depending on which tracking control is being performed. Therefore, the output of the differential amplifier (55) is supplied as is to one input terminal of the switch circuit (57), and the polarity is inverted by the inverter (58) and supplied to the other input terminal. Further, the output of the differential amplifier (56) is supplied as is to one input terminal of the switch circuit (59), and its polarity is inverted by the inverter (60).
supplied to the other input end. And the switch circuit (5
7) is switched by the output of the differential amplifier (56), and the switch circuit (59) is switched by the output of the differential amplifier (55).

That is, for example, when the difference between pilot signals P2 and P4 is obtained from the differential amplifier (56), an output is obtained from either the filter (51) or the filter (53). When the output is obtained from the filter (51), it is the time to scan the track (4A1).
A higher level output can be obtained than the differential amplifier (55),
The switch circuit (59) is switched to the state shown in the figure. When output is obtained from the filter (53), the track (4
A3) should be scanned, but the differential amplifier (55
), a lower level output is obtained than the switch circuit (5
9) is switched to a state opposite to that shown in the figure, and an output obtained by inverting the polarity of the output of the differential amplifier (56) is obtained from this switch circuit (59).

The switching of the switch circuit (57) is done in exactly the same manner.

In this way, the tracking control signal for the head (IB) is transmitted from the switch circuit (57) to the switch circuit (59).
) respectively obtain tracking control signals for the head (IA).

The outputs of these switch circuits (57) and (59) are supplied to one and the other input terminals of the switch circuit (61),
This switch circuit (61) is switched in °C in synchronization with the switch circuit (34) by the output switching signal Sl+ of the head (IA) (IB), and synchronization between the head switching and the tracking control signal of the head is achieved. It will be done.

The output of the switch circuit (61) is connected to an integrator circuit (
62) to the adder circuit (63).

Then, a speed servo signal from a capstan speed servo circuit (29) having the same configuration as that used during recording is supplied to this adding circuit (63), and a signal obtained by adding the above-mentioned tracking control signal to this speed servo signal is This addition #J
It is supplied from R (63) to the capstan motor (27) and 'ζ tracking control is performed.

In the above manner, a pilot signal is inserted into the rack, and the reproduction output of the pilot signal from the adjacent tracks on both sides can be used to control the tracking of the C rotary head. Moreover, in this case, since the recording position of the pilot signal is approximately at the center of each track, the optimal tracking position can be achieved even during variable speed reproduction. In other words, when the tape speed is twice the normal speed, the scanning locus of the widthwise center of the head gap of the rotating head is as shown by the dashed line (71) in FIG. When the tape speed is three times the normal speed, the tracking servo is applied as shown by the dashed line (72) in FIG. This is because, in the pilot signal recording position portion, servo is applied so that the pilot signal components of the tracks on both sides of the main scanning track are equal.

In addition, in this example, even though the PCM data and the pylon signal are recorded on the same trunk, the recording positions are completely separate and independent, so so-called overriding is easy. That is, for example, it is conceivable to record a signal to be recorded and a pilot signal in a superimposed manner, but in that case, the pilot signal is usually set to an extremely low frequency so that it can be separated in terms of frequency. However, if the pilot signal has a low frequency, it will not be erased and will remain without being erased during override, resulting in poor override characteristics.

On the other hand, since the pilot signal frequency is not superimposed and is recorded separately, it is important to arbitrarily determine the pilot signal frequency. It is easy to select a value that does not cause deterioration.

Note that the above example is for a two-head rotary head device, and the tape winding is a special case where the angle is 90°. Needless to say, it can be applied as is to a case where the angle is 180 degrees. It goes without saying that the present invention is applicable not only to two heads but also to one head or to a rotary gutter device with two or more heads.

Furthermore, the pilot signal can have three frequencies instead of four.

Effects of the Invention According to the present invention, a tracking control signal is recorded at the end of the tape using a fixed head, and a pilot signal is recorded along with a recorded information signal almost at the center of one track without being played back. During playback, tracking control can be performed by using the pilot signal playback outputs from adjacent tracks on both sides. Moreover, in this case, even during still playback or playback at variable speeds such as double speed or triple speed, the pilot signal recording position is at the center of the track, so the rotary head is always brought to the optimal tracking position. be able to.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a rotation/gutter device of an example of the device of this invention, Fig. 2 is a diagram showing its recording track pattern, and Fig. 3 is a diagram showing a recording track pattern thereof.
Figure 4 is a block diagram of an example of the recording system, Figure 4 is a time chart for explaining the operation of the recording system, Figure 5 is a block diagram of an example of the reproduction system, and Figure 6 is the reproduction system. FIG. 2 is a time chart for explaining the operation of FIG. (LA) (IB) is a rotating head, (2) is a tape, (2
1) is a pilot signal generation circuit, (25) is a capstan, and (27) is a capstan drive motor. No. 1m1 Procedural amendment May 11, 1981 Kazuo Wakasugi, Commissioner of the Patent Office, Indication of the case 1987 Patent application No. 197173 2, Name of invention recording and reproducing device 3, Person making the amendment Related Patent Applicant Address No. 6-7-35 Tokyo Parts Illustrated Product Name (2
18) Sony Corporation Representative Director Nori Ohga tiC 4, Agent 5, Date of amendment order Showa year, month, day, i
ll In the drawings, Figure 2 has been corrected as shown in the attached sheet.

Claims (1)

[Claims] In a device in which signals for a unit time are recorded as one diagonal trunk on a recording medium by a rotary head, and the signals are reproduced by scanning the rotary head on the diagonal track, A pilot signal is recorded approximately in the center of the rotating head in the scanning direction in a state that it can be separated from the signal to be recorded,
A recording/reproducing apparatus in which this pilot signal is used as a tracking control signal for a rotary head during reproduction.