JPS62273642A - Rotary head type recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent accidental erasure in response to the desire of a user by using the 2nd head so as to trace a medium in preceding over the 1st head thereby reproducing the signal and using the said signal to inhibit the recording. CONSTITUTION:Rotary heads 17, 18 extract a reproducing signal from a region A2 on a tape 1 in preceding over rotary heads 15, 16 at recording and its reproducing signal is fed to a detection circuit 44. That is, whether the part to be recorded from now is recorded or unrecorded is detected by using the heads 15, 16. An operation section section 42 designates the mode applying recording to the unrecorded part or the mode recording to the recorded part. In the mode applying recording to the unrecorded part only, with an output coming from the circuit 44, a system controller 43 releases the recording state thereby inhibiting the signal recording. Thus, since the accidental erasure is prevented in response to the desire of the user, the utilization of the tape with high frequency is attained.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a rotary head type recording/reproducing device.

In particular, the present invention relates to a rotary head type recording and reproducing apparatus that records and reproduces a signal obtained by processing information in real time and a signal obtained by compressing the information on the time axis on the same recording medium.

<Prior art> This type of device frequency-multiplexes a signal obtained by modulating an analog audio signal with 7M and video No. 1, records and reproduces this using a rotary head, converts the analog audio signal into PCM, and further time-multiplexes the signal. A type of video tape recorder (VTR) that performs axial compression and records and plays back on the same tape using a rotating head has been proposed and implemented.

Hereinafter, the above-mentioned VTR will be briefly explained.

FIG. 5 is a diagram showing a main part of a tape running system of a conventional VTR of this type, and FIG. 6 is a diagram showing a pattern recorded on the tape by the VTR of FIG. In the figure, 1 is a magnetic tape, 2.3
4 is a rotating head, 4 is an fc rotating cylinder that fixes the rotating head 2.3, and 5 and 6 are tape guide members. In the angular range of 18o0 indicated by V in M, heads 2 and 3 receive video signals and signals. The head 2.3 records and reproduces the M-modulated audio signal, and the head 2.3 records and reproduces the time-axis compressed PCM audio signal in an angular range of 30 @ indicated by M. Maft D
t is an arrow indicating the running direction of the tape 1, and D is an arrow indicating the rotating direction of the rotary head. Also, M i is the area traced while the heads 2 and 3 rotate in the angular range of V, and A is the area traced by the heads 2 and 3.
is the area that is traced while rotating the angular range of the gam.

Next, the recording/playback timing of the time-base compressed PCM audio signal will be explained. Figure 7 shows time axis pressure at PCM
This is a friend's diagram to explain the processing timing of the audio signal.In Figure 1, the rotational phase detection signal of PG heads 2 and 3 shows that head 2 is tracing area A.
This signal is at a low level during tracing.

Now, the nine audio signal data sampled in the period t1 to t2 are subjected to signal processing such as changing the data arrangement and layering of redundant data such as error correction codes in the period t2 to t3, and are converted into PCM. Axial compression from t3 to t4
recorded on the recording medium for a period of . Also t3-t4
The 72 paM audio signal played during the period of t
During the period from 4 to t5, signal processing opposite to that during recording is performed, and at t5
It is output during the period from to t6.

On the other hand, video signal and signal? The M-modulated audio signal is processed and recorded/played in real time.

<Problems to be Solved by the Invention> As is clear from the above description, the audio signal reproduced from area 4 is reproduced from area A1, causing a time delay with respect to the video signal and audio signal. This delay time is indicated by τ in the vg7 diagram, and if a video signal for each track Vc1 field period is recorded, τ becomes 2.8 field frequency.

Therefore, the sound obtained from the reproduced FM audio signal and the reproduced P
The audio obtained from the CM audio signal may have a time lag, so if you have recorded signals related to the same audio and output both of these playback audio at the same time, there will be an echo and the sound will be distorted. Put it away. Furthermore, the above-mentioned time lag also poses a problem when a configuration is adopted in which audio signals of different channels are recorded and reproduced in areas A8 and A4.

Furthermore, a time lag also occurs between the video signal and the reproduced PCM audio signal. Generally, the difference between the video output and the audio output is not a problem if it is about 3 field periods, but if dubbing is performed n times, the time difference becomes 3n field periods and the difference between the video output and the audio output becomes It becomes noticeable.

On the other hand, in order to prevent accidental erasing in this type of VTR, it was generally done by breaking the claws of the tape cassette to prevent accidental erasing on the entire tape cassette. I can't do that. Furthermore, once the nail is broken, signals cannot be recorded even in the unrecorded areas, so a more flexible measure for users to prevent accidental erasure is desired.

In view of the above-mentioned background, the present invention is capable of real-time processing the playback output of a signal recorded through time axis compression processing to match the recorded next playback output, and is easy to use. It is an object of the present invention to provide a rotary head type recording/reproducing device that can prevent erroneous erasure.

Ninth Means for Solving the Problems〉 For this purpose, in the rotary head type recording/reproducing device flK of the present invention, information is transmitted to a first area extending in the longitudinal direction of a tape-shaped recording medium. a first rotary head for recording and reproducing a first signal processed in real time, and recording a second signal obtained by time-axis compressed information in a second area parallel to the first area; a second rotary head that traces the medium in advance compared to the rotary head and reproduces the second signal from the second area; A configuration is adopted which includes means for prohibiting the recording of signals by the rotary head.

<Operation> By configuring as described above, the reproduction timing of the second signal can be made earlier than the time delay amount associated with the time axis compression processing, and the reproduction information by the second signal can be processed in real time. It can now be handled in the same way. , t, said second
Since the head traces the recording medium before the first head, it can be determined whether or not to inhibit recording before the first head performs recording.

It is extremely easy to use and can prevent accidental erasure.

<Example> Hereinafter, one embodiment of the present invention will be exemplified and explained.

FIG. 1 is a block diagram showing the configuration of a VTR according to an embodiment of the present invention, and FIG. 2 is a timing chart showing waveforms of various parts in FIG.

First, regarding the head configuration of the VTR shown in Figure 1, Figure 3 (A)
, (B'). In Figure 3 (m),
15.16 have different azimuth angles, 9180"
a rotating head that rotates with a phase difference of 17.18
are rotating heads having the same azimuth angle as heads 15 and 16, respectively, and rotating with a phase difference of 180' from each other. Rotating head 17.18 is rotating head 15.115 K
It is assumed that the rotating heads 15 and 16 rotate with a phase difference of 90'', and trace the tape 1 ahead of the rotating heads 15 and 16.

Figure 3 (As shown in Bl, the rotational surface of the head 17.18 with respect to the head 15.16 is 3.5 track pitch (Tp)
Shift and b. If the direction of rotation is in the direction indicated by the arrow in FIG. 3(B), the position of each head on the tape 1 will be as shown in FIG. 4, with heads 17, . 18 means that each track is traced 3.5 fields in advance.The operation of the VTR shown in FIG. 1 will be explained below.

First, during recording, the system controller 43 connects the switch 28 to R11ll and turns on the switch 27. Just in case there is a small input from terminal 21, the audio signal is I
The signal is supplied to the FM audio signal recording processing circuit 24 and the paM audio signal recording processing circuit 23, where well-known processing is performed. On the other hand, the video signal inputted to the terminal 22 is sent to a video signal distribution processing circuit 25 where the luminance signal is subjected to FM modulation and the chroma signal is subjected to low frequency conversion, and then supplied to a mixer 26 .

The mixer 26 performs mixing so that the FM modulated audio signal outputted from the PM audio signal recording processing circuit 24 is placed in a band between the IFM modulated luminance signal and the low frequency converted chroma signal.

'The nine PGs mentioned above are supplied to the terminal 20, and the selected PG
The switch 31 is switched to 31111 at the timing when the head 15 traces the area A1t, and to 31111 at the timing when the head 16 traces the area A. Area A,
It will be recorded above.

? This is an edge detection circuit that detects the edges of the dPG. The output signal of this circuit 9 triggers the monomulti 10, and the monomulti 10 goes low at the timing when the head 15 or head 16 traces the area A as shown in FIG. Outputs a level signal. As shown in FIG. 2, the NOR gates 11 and 12 output signals that go high at the timing when the respective heads 16 and 15 trace the area A, and these output signals control the switches 29 and 50. As a result, the time axis is compressed and the nine audio signals output from the PCM audio signal enhancement processing circuit 25 are output from the head 15.
．． 16 is recorded on area A.

Next, the operation during playback will be explained. During playback, the system controller 43 connects the switch 28 to P@ and turns on the switch 39. The switch 31 is controlled at the same timing as when recording and recording, and the heads 15 and 16 are controlled in the area where they receive the video signal described above. A mixed signal of the M modulated signals is sent to the video signal reproduction processing circuit 32 through the P side terminal of the switch 28. ? The output signal is supplied to an audio signal reproduction processing circuit 55. Video signal reproduction processing circuit 32. A video output signal and an audio output signal (2) are obtained from the PM modulated audio signal reproduction processing circuit 33, respectively, and are output from the terminal 3.
Output from 4.35.

Head 17.18, which traces 3.5 fields ahead of head 15.16 on the other hand, is in area A, 'lk: tray.
Switches 37 and 58 are turned on at the timing when the driver enters the vehicle. That is, since the rotational phase of the heads 17° and 18 is shifted by 90' with respect to the heads 15 and 16, the phase of the output signal of the monomulti 10 is shifted by 9011 with a 90° phase shift circuit and is supplied to the signals 13 and 14. In particular, a signal as shown in FIG. 2 is obtained to control the switches 57 and 38.

Therefore, from heads 17 and 18, the time axis compressed PCM
The audio signal is extracted and transferred to the PCM audio signal reproduction processing circuit 40 via a switch 39 that is turned on during reproduction.
supplied to PCM audio signal reproduction processing circuit 40
The audio signal outputted from the above-mentioned audio signal is 2.8 fields fr! Head 17.18 is delayed by 4 degrees, but head 15. In order to trace 3.5 fields ahead of L6, the audio signal output from circuit ant is approximately 0.7 fields ahead of the audio signal output from circuit 63. The delay circuit 46 compensates for this advance and adjusts the timing of the audio signal output from the terminal 41 to the video signal output from the terminal 34).
This is to match the output audio signal.

Next, the accidental erasure prevention operation according to this embodiment will be explained.

During recording, signals are not recorded by the heads 17 and 118. During recording, heads 17° and 18 are heads is,
Prior to step 16, a reproduced signal is picked up from area A on the tape, and the reproduced output signal is supplied to a detection circuit 44. Tsuma υ
, heads 15 and 16)) It is detected whether the portion to be recorded is already recorded or unrecorded.

On the operation unit 42, in addition to specifying modes such as record and r+raw, it is also possible to specify a mode in which recording is performed only on unrecorded portions, or a mode in which recording is also possible on recorded portions. In the mode in which recording is performed only in the detection circuit 44
If there is more output, the system controller 43 cancels the recording state and prohibits recording of the signal.

In the above-mentioned VTR, the reproduction output timing of the audio signal recorded and reproduced with time axis compression can be perfectly matched with the video signal and audio signal recorded and reproduced through real-time processing.

According to this, it is possible to record and play back, for example, a signal of another channel of a stereo audio signal in the Ahlir area. Also, no matter how many times you dub, the timing of the video signal and the audio signal recorded and played back with time axis compression will not deviate. do not have.

Please note that it is possible to prevent accidental erasure according to the user's wishes, and since accidental erasure prevention is not applied to the unrecorded portions that do not need to be protected against accidental erasure IJ-7, tapes can be used efficiently. It became.

In the above-mentioned embodiment, the head 17.18 detects whether or not a signal is recorded in the area A and prohibits recording. It is also possible to adopt a configuration that detects whether or not the

<Effects of the Invention> As explained above, the feature of the rotary head type recording/reproducing device of the present invention is that the reproduction output of a signal recorded by time-axis EE compression processing matches the reproduction output recorded by real-time processing. At the same time, it is possible to perform accidental erasure prevention which is extremely easy to use.

[Brief explanation of drawings]

Figure 1 shows -! of the present invention. ! ! Block diagram showing the configuration of a VTR as an example, Figure 2 is a timing chart showing the waveforms of each part of the first part, g5 Figure (A), (B) IdfJ, Figure 1 is a diagram showing the OVTRO configuration, 2g4 This figure is a diagram showing the positional relationship of each head shown in FIG. 3 on the tape. FIG. 5 is a diagram showing the main parts of the tape running system of a conventional VTR. FIG. 6 is a diagram showing a recording pattern on the tape in the VTR of FIG. FIG. 7 is a diagram for explaining the processing timing of a time @llI compressed PCM audio signal. Reference numeral 1 indicates a 7-iron tape, 15.16 a head as a first rotary head, 17.18 a head as a second rotary head, 23 a PCM audio signal recording processing circuit, and 24 an FM audio signal recording circuit. recording circuit,
25 is a video signal recording processing circuit, 32 is a video signal reproduction processing circuit, 33 is an FM audio signal reproduction processing circuit, 4
a is a POM audio signal reproduction processing circuit, m is a first area b't is a second area.

Claims (1)

[Claims] A device for recording and reproducing signals on a tape-shaped recording medium using a rotary head that traverses the medium, wherein a first signal is obtained by processing information in real time on a first area extending in the longitudinal direction of the medium. a first rotary head for recording and reproducing a second signal obtained by compressing information in a time axis in a second area parallel to the first area; a second rotary head that traces the second signal in advance and reproduces the second signal from the second area; and recording of the signal by the first rotary head using the reproduction output of the second rotary head. A rotary head type recording/reproducing device comprising means for inhibiting.