JPH01179251A - Information signal reproducing device - Google Patents

Abstract

PURPOSE:To perform detection with high accuracy at every track unit by providing a lock means to stop a rotary head at a prescribed angle, performing the detection of an index signal on an oblique track at the time of performing fast research, and stopping the rotation of the head. CONSTITUTION:A magnetic tape is fed at high speed at the time of performing the research of an index, and the movable contact 37m of a change-over switch 37 is connected to a fixed contact 37a on one side to obtain the reproducing signal of the head HA. And the rotation of a drum motor 39 is stopped by a drum rotation control circuit 38, and the head HA is fixed at a position corresponding to the height of an index signal recording area (i) on the magnetic tape 2. The locus Hi of a fixed head HA traces on the index signal recording area (i) on tracks 4A and 4B, then the index signal is reproduced. By constituting a device in such way, it is possible to detect index information with high accuracy at every track unit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information signal reproducing device suitable for application to, for example, a VTR1 digital audio tape recorder (DAT) called 8 mm video.

[Summary of the invention]

The present invention is an information signal reproducing apparatus that is applied to, for example, 8 mm video, DAT, etc. and uses a rotary head to reproduce information signals recorded by forming inclined tracks on a suitable tape. By providing a locking means to stop the rotation at , and detecting the index signal recorded on the inclined track during high-speed search by stopping the rotation of the rotary head using the locking means, it is possible to perform one track with a simple configuration. This allows for highly accurate index searches that can be detected in units.

[Conventional technology]

Conventionally, a so-called 8 mm video has been developed as a video tape recorder that records video signals on a magnetic tape having a width of 8 mm. In the case of this 8mm video, the audio signal is frequency modulated and mixed with the color video signal in a state where it can be separated in frequency and recorded. An embodiment may be adopted in which the two are separated and one track is formed for recording.

Figure 3 shows an example of an 8mm video rotating head device.
FIG. 4 shows the tape former throat.

In Fig. 3, HA and HB are rotating magnetic heads for recording and reproduction.
The azimuth angles of the operating gaps of these heads HA and HB are made to be different from each other, and 180 degrees
They are mounted at angular intervals of 100 degrees and are rotated in the direction of the arrow (3H) at a frame frequency of 307 while protruding slightly from the surface of the drum (1). Then, the magnetic tape (2) is wound around the circumferential surface of the drum (1) over an angular range of 221 degrees, and is run at a constant speed in the direction of the arrow (3T).

Therefore, as shown in FIG. 4, tracks (4A) and (4B) each having a length of 221 degrees are alternately formed by the rotating nodes HA and HB, and signals are recorded on the tape (2). , tracks (4A) and (4B), an area AP of an angular range of 36 degrees from the time when the rotary heads HA and HB start scanning (including the post-recording margin and guard hand for the PCM audio signal) contains the video signal. The audio signal related to one field is converted into PCM and recorded in a time-axis compressed state, and the subsequent 180-degree angular range AV contains the color video signal for one field. FM audio signals and further tracking signals are recorded. The remaining 5 degrees is a margin period when the head separates from the tape.

By the way, the track formant of the above-mentioned 8mm video will be explained in more detail as shown in FIG. That is, in the same figure, on the right side where the rotating head begins to come into contact with the tape (2), first, at the tip, the 5 degree rotation angle of the head is defined as a plunge part (11), and the latter half of this plunge part (11) is 2
．． The period of 06 degrees (corresponding to 38 (H is horizontal period) of the video signal) is a preamplifier that becomes the clock run-in part that synchronizes with PCM data, which will be described later! (12).

Following this preamble section (12), there is a recording area (13) for PCM data of the time-axis compressed audio signal.
It is provided over 32 degrees. The period < 2.06 degrees 3H following this PCM data recording area (13) is a postamble section (14) that serves as a back margin against recording position deviation during after-recording, and the subsequent 2.62 degrees is a It serves as a guard section (15) between the signal section and the PCM data section. Following this guard section (15) is a recording area (16) for one field's worth of video signals.
) is provided over 180 degrees. Furthermore, the subsequent 5
The distance is defined as a separation part (17).

In addition, PCM data is I"IJ, "OJ data that is modulated and recorded on the tape, but in 8mm video, for example, the data of "1" is 5.8! JHz, rO
” data is 2.9! It is modulated and recorded as a JH2 signal, and the preamble! (12) and the postamble section (14) have conventionally been all "1" data, that is, 5.8! AHz signals are recorded.

By the way, in the above-mentioned 8mm video, as a method for cueing, an index signal is recorded in, for example, the postamble section (14) of each of the above-mentioned trunk formats, and this index signal is used for cueing. (Japanese Patent Application No. 60-64554).

According to the previously proposed invention, the index signal can be recorded and reproduced using a rotating head, so there is no need to provide a dedicated fixed head, and it is also possible to easily input or erase the index signal later. It has characteristics.

[Problem that the invention seeks to solve]

However, when detecting the index signal recorded on the inclined track in this manner, there is an inconvenience that the index signal cannot be detected unless the track is traced track by track with a rotary head. That is, with this type of VTR, for example, 9
When performing a double-speed search, the head trajectories h1, h2, etc. scan nine trunks at a time, as shown in Fig. 6, so the index signal recording area 1
The head scanned only one trunk out of 49 tracks, and the index signals recorded on the remaining tracks could not be detected. Therefore, in order to reliably detect the index signal, it is necessary to scan one track at a time at normal speed.

In order to solve this problem, for example, in the case of a VTR that performs a high-speed search of 9 times the speed, it is conceivable to write the same index signal continuously on nine or more tracks. By doing so, even during a high-speed search of 9 times the speed, it is possible to detect the index signal of any consecutive track and perform cueing, etc.

However, when the same index signal is written to multiple tracks in this way, the number of tracks specified by one index signal increases accordingly.For example, if the same index signal is written to 9 tracks,
There is a possibility that the detection position may be shifted by up to 9 tracks, which is disadvantageous in that the detection accuracy based on the index signal deteriorates.

In view of this, it is an object of the present invention to provide an information signal reproducing device of this type that is capable of highly accurate detection in units of trunks even during high-speed searches.

[Means for solving problems]

As shown in FIG. 1, for example, the information signal reproducing apparatus of the present invention is an information signal reproducing apparatus for reproducing information signals recorded by forming inclined tracks on a tape using rotary heads HA and HB. , a locking means (3B) for stopping the rotation of the HB at a predetermined angular position is provided, and the rotation of the rotary head HΔ, HB is controlled by the locking means (38>) during high-speed search of the index signal recorded on the inclined track. This is done by stopping the operation.

[Effect]

According to the present invention, during a high-speed search, the locking means (38) fixes the rotary head HA (or HB) so as to match the position (height) of the index signal recording area on the tape, so that this rotation is prevented. The HA (or HB) traces the index signal recording area regardless of the tape speed, and the index signal can be detected on a track-by-track basis, making it possible to perform a highly accurate index search on a track-by-track basis.

〔Example〕

Hereinafter, one embodiment of the information signal reproducing apparatus of the present invention will be described with reference to FIGS. 1 and 2. This figure 1 and 2
In the figures, parts corresponding to those in FIGS. 3 to 6 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

This example is applied to an 8 mm video recording/playback device. In Fig. 1, a video signal input terminal (21) and an output terminal (22) are connected to a video signal processing circuit (23). The output side of the recording signal of the processing circuit (23) is the first one of each of the recording signal changeover switches (24) and (25).
It is connected to fixed contacts (24a) and (25a) of. Furthermore, the input terminal (26) and the output terminal (27) for each of the two channels of audio signals are connected to a PCM audio signal processing circuit (28).
) is the output side of the recording signal of Sui-Sochi (24) and (25).
), respectively second fixed contacts (24b) and (25b
) connected to. Furthermore, the system control circuit (29) is connected to the index signal modulation/demodulation circuit (30), and the recording signal output side of this modulation/demodulation circuit (<30) is connected to the third fixed contact (24) and (25), respectively. 24c) and (25c). The movable contacts (24n+) and (25m) of these switches (24) and (25>) connect to the rotating drum (33) through the recording amplifiers (31) and (32), respectively.
Rotary helmet H provided above at angular intervals of 180 degrees from each other
Connected to A and HB.

In addition, rotating heads HA and ) (B are respectively playback amplifiers (
34) and <35), one fixed contact D6a) of +i changeover switch (36) and (37)
and the other fixed contact (37b).

The movable contact (36 m) of this switch (3G) is connected to the input end of the playback signal of the video signal processing circuit (23).The movable contact (37 m) of the switch (37)
are commonly connected to the input terminals of the reproduction signal of the PCM audio signal processing circuit <28> and the index signal modulation/demodulation circuit (30), respectively. In addition, each selector switch (
24L <25), (36), (37) switching is as follows:
The system control circuit (29) outputs the signal.

The drum rotation control signal outputted from the system control circuit (29) is then supplied to the drum rotation control circuit (38). This drum rotation control circuit (38) is connected to a drum motor (39) that rotates the rotary rods HA and HB.
This is a circuit that controls the rotation of. And the drum motor (
39), the detection signals of the pulse generator (40) for detecting the rotational speed and the frequency generator (41) for detecting the rotational phase are
This is to be supplied to this drum rotation control circuit (38). This drum rotation control circuit (38) is
The rotation angle positions of the rotary heads HA and HB are detected by the detection signals from the pulse generator (40) and the frequency generator (41), and the drum motor (39) is controlled by the control signal supplied from the system control circuit (29). ) can be stopped at a predetermined phase, and the rotating heads HA and HB can be stopped at a predetermined angle. In this example, the rotary heads HA and HB are stopped during an index search in which the magnetic tape (4) is run at high speed and an index signal is detected. At this time, according to a command from the system control circuit (29), the position of the rotary head HA with respect to the magnetic tape (4) is adjusted to the recording track (4A) on the magnetic tape (2), as shown in FIG.
, (4B) to the angular position at a height corresponding to the height of the index signal recording area 1 from the bottom edge of the tape.

Next, we will explain the operation when recording an index signal together with a video signal and an audio signal in the recording/reproducing apparatus of this example. While rotating at a constant speed, press the recording signal changeover switch (24) and (2).
5) are alternately switched in conjunction with the scanning position on the tape. In other words, at the point where the video signal is recorded, the changeover switch (2
4) and (25) movable contacts (24m) and (25m)
the first fixed contacts (24a) and (25a), respectively.
The movable contacts (24m) and (25m) are connected to the second fixed contacts (24b) and (25b) at the recording location of the PCM audio signal, respectively, and the movable contact (24m) is connected to the second fixed contact (24b) and (25b) at the recording location of the index signal. as well as(
25m) to the third fixed contact (24C) and (25m) respectively.
c).

During playback, the playback signal selector switches <36) and (37) are alternately switched depending on the scanning position on the tape to supply the playback video signal to the video signal processing circuit (23) and the PCM audio signal processing circuit (28). )
and the index signal modulation/demodulation circuit (30) to supply the reproduced PCM audio signal.

The index signal modulation/demodulation circuit (30)
When the index signal recorded in the postamble part in the M audio area is supplied, this index signal is demodulated and supplied to the system control circuit (29).

Next, to explain the operation during index search, for example, when performing an index search, the magnetic tape is
00 times the speed, and the movable contact (37m) of the changeover switch (37) is connected to one fixed contact (37a) from which the reproduction signal of the rotary head HA is obtained. Then, the drum motor (39) is controlled by the drum rotation control circuit (38).
rotation is stopped, and the rotary head HA is fixed at a position corresponding to the height of the index signal recording area l on the magnetic tape (2) as shown in FIG.

By doing this, this fixed rotating head HA
The trajectory Hi is for each track (4A), (4B)
The index signals recorded in the index signal recording areas l of all tracks are traced regardless of the tape speed. For this reason, RadH to a fixed rotation
The index signal recorded by the running of the tape is supplied from A to the index signal modulation/demodulation circuit (30) via the changeover switch (37), and the system control circuit (29) outputs the index signals of all the tracks one track at a time. can be detected. Note that the index signals of both azimuth angles recorded by the magnetic heads HA and HB are detected by the magnetic head HA of one azimuth angle, but since the head HA has stopped rotating, the playback frequency is Since there is no azimuth loss, a good index signal can be detected regardless of the azimuth angle.

As described above, according to the playback device of this example, the index signal can be reliably detected on a track-by-track basis even during index search with a simple configuration that only requires stopping the rotary head. Therefore, there is no need to record the same index signal over a plurality of tracks, and there is an advantage that a highly accurate index search can be performed in l-track units.

Although the above-mentioned embodiment has been described as an example in which the present invention is applied to 8 mm video, it goes without saying that the present invention can also be applied to various information signal reproducing apparatuses such as DATs in which index signals are recorded in the same manner.

Furthermore, it goes without saying that the present invention is not limited to the above-described embodiments, and that various other configurations can be adopted without departing from the gist of the present invention.

〔Effect of the invention〕

The information signal reproducing apparatus of the present invention has the advantage of being able to perform a highly accurate index search that allows detection on a track-by-track basis with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the information signal reproducing device of the present invention, FIG. 2 is a route diagram for explaining the example in FIG. 1, and FIG. 3 is a block diagram showing an example of a rotating head device. Figures 4 and 5
The figure is a recording track pattern diagram of an 8 mm video, and FIG. 6 is a route map showing the state during a conventional index search. (29) is the system control circuit, (3B) is the drum rotation control circuit, (39) is the drum motor, HA and H
B is a rotating magnetic head.

Claims (1)

[Scope of Claims] An information signal reproducing device for reproducing information signals recorded by forming inclined tracks on a tape using a rotary head, further comprising a locking means for stopping rotation of the rotary head at a predetermined angular position; An information signal reproducing apparatus characterized in that detection of an index signal recorded on an inclined track during a high-speed search is performed by stopping rotation of the rotary head using the locking means.