JPS61144703A - Rotary head type recording device - Google Patents

Abstract

PURPOSE:To grasp the recording state of all areas by dividing a tape type recording medium lengthwise into plural areas, recording a pilot signal of specific frequency upon an information signal, and detecting the generation timing of the pilot signal. CONSTITUTION:The magnetic tape 1 is dived lengthwise into plural areas and the information signal is recorded in each area by rotary heads 3 and 4 which traces the tape 1 in its width direction. When the signal is recorded, a pilot signal f5 of specific frequency lower than the exclusive use band of the information signal and a pilot signal for tracking which is generated by a pilot signal generating circuit 23 are recorded upon all information signals from a PCM audio circuit 22. When they are reproduced, the signal f5 in outputs of the heads 3 and 4 is detected by an area decision circuit 28 through a gate circuit 27 which is controlled with output pulses of a gate pulse generating circuit 17 and the circuit 28 decides whether each area is already recorded or not, so that the result is displayed on a display device 29. Thus, the recording state of all the areas is grasped.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a rotary head type recording device, and in particular, a tape-shaped recording medium is divided into a plurality of regions in the longitudinal direction, and each region is recorded by a rotary head that traces in the width direction. The present invention relates to a device for recording information signals on a computer.

<Description of the Prior Art> In recent years, high-density recording has been pursued in the field of magnetic recording, and even in video tape recorders (VTRs), tape running speeds have been reduced to perform even higher-density magnetic recording. There is. Therefore, if audio signals were recorded using a fixed head as in the past, the relative speed could not be kept high and the reproduced sound quality would deteriorate.

One solution to this problem is to make the length of the track formed by the rotary head longer than before, and to sequentially record time-base compressed audio signals on the extended portion.

For example, in a rotating two-head helical scan type VTR, a magnetic tape has conventionally been wound around a rotating cylinder by more than 180 degrees.

A VTR has been devised in which a rotary shilling is wound with a length of (180+θ)0 or more, and an audio signal converted into PCM and time-axis compressed is recorded on the excess wound portion. FIG. 1 is a diagram showing a tape running system of such a VTR, and FIG. 2 is a diagram showing a recording locus of a magnetic tape L by the VTR shown in FIG.

In the figure, l is a magnetic tape, 2 is a rotating cylinder, and 3.4
are heads with mutually different azimuth angles attached to cylinder 2 with a phase difference of 180°.

5 is a video area of a track formed on the tape 1, and 6 is an audio area. Video area 5
is the portion where the head 3.4 traced the tape at the 1800th minute of the rotary cylinder 2, and the audio area 6 is the portion where the head 3.4 traced the tape at the 00th minute of the rotary cylinder 2. In addition, f1 to f4 in Fig. 2 indicate the frequencies of tracking pilot signals superimposed on each track using a similar 4-frequency system, and the relationship between the frequencies is (f2 - f
t)=f3-f4, f)l, and f4-f2+2fH. However, fH indicates the horizontal scanning frequency of the video signal.

The sound quality when playing back the audio signal which has been converted into PCM and time axis compressed in the audio area in this way is quite high and is comparable to the sound quality of an audio dedicated device that records and plays back analog signals.

On the other hand, a proposal has been made to record another audio signal in the video area 5 of the above-mentioned VTR. That is, for example, when θ=36, if the rotary head rotates for 1800 minutes, there will be 5 other audio areas such as 6.
There will be one. By recording time-base compressed audio signals independently in each area, an audio-only tape recorder capable of recording a total of six channels of audio signals can be obtained.

This tape recorder will be briefly explained below. FIG. 3 is a diagram showing the tape running system of the above-mentioned tape recorder, and FIG. 4 is a diagram showing the recording locus on the tape by this tape recorder. Note that the numbering is the same as in FIGS. 1 and 2.

In FIG. 4, CHI NCH 6 corresponds to head 3 or head 4, respectively, from A to B in FIG.

This is an area in which an audio signal is recorded during the period of tracing from B to C, from C to D, from E to F, and from F to G. It is possible to record audio signals separately in each area, and so-called azimuth overwriting is performed in each area, but the tracks in each area CHI to CH6 do not need to be on the same straight line, and each area Pilot signals for tracking control are recorded in each area, and it is assumed that they are recorded in a predetermined rotation (ft→f2→f3→f4) for each area.

There is also no correlation between these areas.

Also, the area indicated by CHI to CH3 is tape 1 in FIG.
Recording and reproduction are performed when the vehicle is traveling at a predetermined speed in the direction shown by arrow 7, and recording and reproduction is performed in the area indicated by CH2-CH2 when it is also traveling in the direction shown by arrow 9. Therefore, the fourth
As shown in the figure, the slope of each track in the area shown by CHI to CH3 is slightly different from the slope of each track in the area shown by CH2 to CH2. However, regarding the difference in relative speed at this time, the difference in relative speed due to the running of the tape l is extremely small compared to the difference due to the rotation of the heads 3 and 4, so it does not pose a problem.

FIG. 5 is a time chart of recording and reproduction of the tape recorder as described above. In FIG.
It is a 30Hzc7) square wave that repeats "high level (H)" and "low level (L)" at 0 seconds.Also, (b) is a PG with the opposite polarity to PG (a).Here, PG (a)
are H, PG while the head 3 rotates from B to G in Figure 3.
In (b), it is assumed that the state is H while the head 4 similarly rotates from B to G.

Figure 5 (C) shows the data reading pulse obtained from PG (a), which corresponds to one field of the video signal (1760 seconds).
This is for sampling the audio signal every other field in the period corresponding to the period corresponding to the period.

In FIG. 5(d), H indicates the signal processing period for adding redundant codes for error correction or changing the arrangement of one field of sampled audio data using a RAM or the like. Figure 5(e) shows the data recording period H.
, which indicates the timing at which the recording data obtained by the above-mentioned signal processing is recorded on the tape l.

For example, if we follow the flow of the signal in time using Fig. 5, t
The data sampled during the period from 1 to t3 (while head 3 is moving from B to G) is from t3 to t5 (when head 3 is moving from G to A)
Signal processing is performed at t5 to t6 (head 3 is A-B)
recorded over a period of That is, the head 3 causes C in FIG.
Recorded in the HI area. On the other hand, data sampled while PG (b) is H is signal-processed at the same timing and recorded in the CHI area by the head 4.

PG (a) at a predetermined phase (here, 36' for l region)
The phase-shifted PG is shown in FIG. 5(f).

Hereinafter, a case will be described in which an audio signal is recorded using PG (f) and a PG (not shown) having the opposite characteristics.

The data sampled from t2 to t4 in FIG.
The signal is processed according to the signal shown in FIG. 5(g) during the period from t6 to t6, and recorded according to the signal shown in FIG. 5(h) during the period from t6 to t7. That is, the data sampled by the head 3 during the period t7 is sent to the CH2 by the head 4.
It is recorded in the area shown in .

Next, the operation of reproducing the signal recorded in the area indicated by CH2 will be explained.

Reading of data from tape 1 by head 3 is shown in FIG.
t6 to t7 (same for tl-t2) according to the signal shown in h)
t7 to t8 (
From t2 to t3), signal processing opposite to that during recording is performed. That is, error correction and the like are performed during this period, and a reproduced audio signal is output from t8 to t9 (t3 to t6) in accordance with the signal shown in FIG. 5(j). Of course, the reproduction operation by the head 4 is performed with a phase difference of 180 degrees from the above-mentioned operation, and thus a continuous reproduction audio signal is obtained.

Also, regarding other areas CH3 to CH6, PG (a)
Needless to say, it is sufficient to shift the phase by n×36° and perform the above-mentioned recording and reproducing operation based on this, and this does not depend on the running direction of the tape.

In this way, the VTR can be used as a multi-channel audio-only device.
can be used. The problem with multi-channel audio-only equipment is that the multiple channels are divided.
It is difficult to understand the usage status of each channel.

゛〈Object of the Invention〉 In view of the above-mentioned background, it is an object of the present invention to provide a rotary head type recording device that is extremely easy to use and allows the recording status of each area to be easily grasped.

<Explanation based on examples> Hereinafter, the present invention will be explained in detail using examples.

FIG. 6 is a diagram showing a schematic configuration of a tape recorder as an embodiment of the present invention. Components in FIG. 6 that are similar to those in FIGS. 1 to 4 are given the same numbers.

PG obtained from the rotation detector 11 of the rotating cylinder 2 is supplied to the motor control circuit 15, which rotates the cylinder 2 at a predetermined rotational speed and a predetermined rotational phase. 12 is a rotation detector of the flywheel 14 of the capstan 13, and is supplied to the output motor control circuit 15 of the rotation detector 12.

During recording, the rotation of the capstan 13 is controlled to a predetermined speed.

On the other hand, the above-mentioned PG is supplied to the window pulse generation circuit 16 and the gate pulse generation circuit 17. FIG. 7 is a timing chart for explaining the phase relationship between the window pulse and the gate pulse with respect to PG.

FIG. 7(a) shows PG, which is at a high level while the head 3 is moving from point B to point G in FIG. Figure 7 (b
) to (g) are window pulses indicating the recording/reproduction timing of each area CHI to CH6, respectively. In FIG. 7, the solid line is for the head 3, and the dotted line is for the head 4.

By manually operating the operation unit 18, operation modes such as recording and reproduction, and areas to be recorded and reproduced are specified. Based on this data, the area designation circuit 19 supplies the area designation data to the gate pulse generation circuit 17 to obtain a desired gate pulse.

The gate pulse for controlling the gate circuit 20 is as follows.

The aforementioned window pulses (shown in FIGS. 7(b) to 7(g)) are selectively supplied to each of the heads 3 and 4 based on the area designation data. Now, if the area shown in FIG. 4 CH2 is designated, the gate circuit 20 is the seventh
It is controlled by the window pulse shown in Figure (C).

During recording, the analog audio signal input from the terminal 21 is sampled at the above-described timing related to the window pulse (C), converted into digital data, and then subjected to the above-described signal processing. The recording audio data obtained in this way is combined with a tracking pilot signal generated by the pilot signal generation circuit 23 in a rotation of fl-f2 → f3 → f4 for each field and a predetermined frequency f5.
a pilot signal (generated by oscillator 60) having
Mixed signal with adder.

24 is added. The output of the adder 24 is sent to the gate circuit 20
The data is gated as described above and written into the area CH2 by the head 3.4.

Therefore, in addition to the tracking pilot signal, a pilot signal having a frequency of f5 is recorded on all tracks together with the PCM audio signal. By the way, the frequency of f5 is not affected by the azimuth angle,
And it needs to be lower than the exclusive band of the PCM audio signal mentioned above.

During playback, the playback signals from the heads 3 and 4 are passed through the gate circuit 20 by the window pulse (e) to the low-pass filter (LPF) 352-J and the PCM audio circuit 2.
2.

Contrary to recording, the PCM audio circuit 22 performs signal processing such as error correction, time axis expansion, and digital-to-analog conversion, and outputs the reproduced analog audio signal to the terminal 21.
Output from a.

The LPF 25 separates the above-mentioned tracking error signal and supplies it to the ATF circuit 26.

The ATF circuit 26 is a circuit for obtaining a tracking error signal using a well-known four-frequency method, and uses a reproduced tracking pilot signal and a pilot signal generated by the pilot signal generation circuit 23 in the same rotation as during recording. It is well known that this is the case. The tracking error signal thus obtained is sent to the motor control circuit 15.
is supplied to the capstan 1 to scan the tape 1 during playback.
3 to perform tracking control.

On the other hand, the gate circuit 27 is controlled by the gate pulses output from the gate pulse generating circuit 17 as shown in FIGS. 7(h) and 7(i). That is, a reproduction signal from an area other than the reproduction area is supplied to the area discrimination circuit 28.

The operation of this area discrimination circuit 28 will be explained below. FIG. 8 is a diagram showing a specific example of this area discrimination circuit 28, and FIG.
The figure is a timing chart for explaining the operation timing of the part shown in FIG.

In FIG. 8, 30.33 is a terminal to which the reproduction signal of the heads 3 and 4 via the gate circuit 27 is supplied, and 31.34
are terminals to which the aforementioned gate pulses (FIGS. 7(h) and (i)) are supplied, respectively, and 32 is a terminal to which PG is supplied.

As is clear from the figure, the circuit configuration consists of a discrimination circuit 37 for the A head 3, a discrimination circuit 38 for the B head 4, and a decoder 47 that converts the outputs thereof from serial to parallel and outputs it as 6-bit data. Incidentally, since the discrimination circuits 37 and 38 have the same configuration, the internal details of one circuit 38 will be omitted.

The operation of the area discrimination circuit 28 will be explained below. Here, for explanation, area CH2 is the playback area, area CH1,
It is assumed that CH4 and CH6 are recorded areas, and areas CH3 and CH5 are unrecorded areas.

The time constant of each monomulti group 42 that is triggered by the rising edge of PG (:fS9 shown in Figure (a)) is such that each output is 9th.
It is determined as shown in Figures (e) to (i). That is, assuming that Δt is a minute time (approximately +×+×+×+ seconds).

Corresponding to the Nth channel counting from CHI, the time constant is expressed by the formula: When N = 1, ΔE (sec), N
When is 2 or more, LL+Δt (s e c).

Next, six types of pulses of a constant width are obtained by the monomulti group 43 which is triggered at the downstream t of the output group of the monomulti group 42. The time constant of each of these mono-multi groups 43 is approximately approximately ×+×4 sec. This pulse (Fig. 9(j)
to (q)), detection can be performed at the center position of each area. All the outputs of the mono multi group 43 are output from the orcate 44.
These are supplied to the AND gate 45 as sampling pulses, while the serial signals of the decoder 47
It is also used as a clock for parallel conversion.

The AND gate 45 performs a logical product between the output of the OR gate 44 and the aforementioned gate pulse (shown in FIG. 9(C)), so that the recording status is identified only for areas other than the playback area. .

On the other hand, the reproduced signal is supplied to the BPF 39, and the pilot signal having the frequency f5 described above is separated. BPF3
9 (shown in FIG. 9(q)) is detected by a detection circuit 40 and then compared with a reference voltage by a comparison circuit 41, and the output of this comparison circuit 41 is sampled by an AND gate 46. This output, that is, a signal indicating the recording status of each area is shown in FIG. 9(1). This signal is outputted from terminals 48 to 53 as parallel data corresponding to each area via a decoder 47.

That is, if each area CHI to CH6 has been recorded, the terminal 48
When the output signal of ~53 is not recorded in H1, it becomes L. These parallel data are supplied to a display 29 consisting of an LED or the like, allowing the user to recognize the recording status of each area.

According to the tape recorder of the above-described embodiment, the recording status of each multi-channel area can be classified by 'l-1' at the same time.

In the above embodiment, the recording status of each area is determined during playback, but the recording status of each area can be determined in the same way whether during recording or high-speed tape feeding. Needless to say, if the magnetic tape 1 can be traced by the rotary head 3.4, the recording status can be immediately determined.

DESCRIPTION OF EFFECTS> As described above, according to the present invention, it is possible to obtain a rotary head type recording or reproducing device that allows the recording status of the entire area to be immediately grasped and is extremely user-friendly for the user.

[Brief explanation of drawings]

Figure 1 shows the tape running system of a conventional VTR, Figure 752 shows the recording locus on the magnetic tape by the VTR shown in Figure 1, and Figure 3 shows the tape running system of a multi-channel tape recorder. FIG. 4 is a diagram showing a recording trajectory with respect to the magnetic tape by the cheap recorder shown in FIG. 3, and FIG. 5 is a time chart of recording and reproduction of the tape recorder shown in FIG. 3. FIG. 6 is a diagram showing a schematic configuration of a tape recorder as an embodiment of the present invention, and FIG. 7 is a timing chart for explaining the phase relationship of window pulses and gate pulses with respect to PG. FIG. 8 is a diagram showing an example of the area discriminating circuit in FIG. 6, and FIG. 9 is a timing chart for explaining the operation timing of the section numbered in FIG. 1 is a magnetic tape as a recording medium, 3.4 is a rotary head, 16 is a window pulse generation circuit, 17 is a gate pulse generation circuit, 28 is an area discrimination circuit, 29 is a display device, 39
is a BPF that separates the pilot signal of a specific frequency, 40
is a detection circuit, and 47 is a decoder.

Claims (1)

[Claims] A device that divides a tape-shaped recording medium into a plurality of regions in the longitudinal direction and records information signals in each region using a rotating head that traces in the width direction. Rotation characterized in that a pilot signal of a low specific frequency is superimposed on all the information signals and recorded, and the recording status of each area is determined based on the generation timing of the pilot signal during output of the rotary head. Head type recording device.