JPH01302503A - Revolving type magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain simultaneous reproducing while preceding reproducing is executed without increasing circuit scale by simultaneously supplying a partial signal from a simultaneous reproducing head and a preceding reproducing head with a switching means which is provided between the reproducing head system of a PCM sound signal and a reproducing signal processing means. CONSTITUTION:The signals of both A and B channels on a tape are reproduced by the simultaneous reproducing head and separated to the PCM sound signal and a video signal by switching circuits 3a and 3b. Then, here, the signals go to multiplexed sound signals CPA and CPB. The signals of the both A and B channels are reproduced by the preceding reproducing head as well and go to be multiplexed sound signals APA and APB respectively. The signals APA, AP', CPA and CPB are conducted by a reproducing mode switching circuit 5. then, by controlling the switching circuit 5, for example, while the preceding reproducing signal APA is reproduced by a reproducing signal processing circuit 6a, the simultaneous reproducing signal CPB can be reproduced by a reproducing signal processing circuit 6b and the immediate monitor of the B channel sound signal, which is already edited, can be executed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to a rotary head type magnetic recording/reproducing device, particularly a VT having a function of recording and reproducing multiple channels of PCM audio signals.
Regarding R.

(Prior technology) Currently, analog VTRs and digital VTs for business use, etc.
In R, an audio signal is recorded as a PCM audio signal on a part of a helical track in the same way as a video signal.

FIG. 5 shows an example of a track format on a tape in such a VTR.

The two tracks in the same figure correspond to one field (1/60 second)
The video signal is recorded by 2-channel divided analog recording, and the audio signal is recorded by 4-channel mutual M recording. That is, the video signal is in the area 51a.
, 51b, and four-channel PCM audio signals are recorded in areas 52a to 52d. A gap is provided between each area, and by erasing or turning on/off recording while the head is scanning this gap, the video signal and four channels of PCM audio signals can all be independently processed. Can be edited.

Figure 6 shows a VT compatible with the track format shown in Figure 5.
The head arrangement on the rotary drum of R is shown. The rotating drum rotates 30 times per second, and the tape is wound around the rotating drum an extra 180' to record the PCM audio signal. RAl, RBl.

RA2. RB2 is a recording head, and RAI and RB
Recording is performed so that I, RA2, and RB2 alternately form a set of two tracks as shown in FIG. 5 for each field. Rotating erase head EAI, EBl, EA2.
EB2 has recording heads RAI, RBI,
RA2. It is arranged to scan just before RB2, and performs erasing prior to recording.

Simultaneous playback head CPAI, CPBL, CPA2°C
PB2 has recording heads RAI, RBI, and R, respectively.
It is arranged so as to scan the position behind (immediately after) A2°RB2, and is used for normal playback and simultaneous playback.

Simultaneous playback refers to confirmation playback at the time of recording, and means that the content recorded on the tape by the recording head is immediately played back and monitored by the simultaneous playback head. This simultaneous playback allows you to check whether the video and audio are being recorded as intended. If simultaneous playback is not possible, the only option is to rewind and play again after recording has finished, so if there is a problem, you will have to re-record the whole thing again, and depending on the source, re-recording is not possible. In some cases. Therefore, simultaneous playback (confirmation playback) is an important function, especially in business-use VTRs.

APAI, APBI, APA2. APB2 is called an advanced playback head, and the mounting height of the head is changed, and there are recording heads RAI and RBI, respectively.

RA2. It is arranged to scan a track at a position several fields ahead of RB2. This advance playback head is used for editing the audio signal.

In other words, while reproducing a recorded PCM audio signal using the advance playback head, some processing is performed on the reproduced signal (for example, mixing with other input signals, mixing between channels, filter processing such as fade-in/fade-out, addition of echo, etc.) After applying this, recording is performed again using the recording head. In this case, the mounting position of the advance reproducing head is set so that the reproduced and processed signal is recorded at the same position on the tape.

As an editing method for PCM audio signals, there are cases where all 4 channels are played back, processed, and then recorded on 4 channels again.
When recording on channel 2 (leaving channels 3 and 4 as is), or when recording on channels 1 and 2,
There are many cases where data is recorded on 4 channels (channels 1 and 2 are not rewritten).

Incidentally, even when a PCM audio signal is edited using the advance playback head in this way, simultaneous playback (confirmation playback) is not unnecessary.

That is, since the source that has already been recorded is erased and a new one is re-recorded, if an abnormality occurs, not only will the editing fail, but important sources will also be lost. Therefore, it is desirable to be able to perform simultaneous reproduction while performing advance reproduction.

However, conventionally, during normal playback and simultaneous playback, the signal from the simultaneous playback head, and during advance playback, the signal from the preceding playback head is selected by a switching means and supplied to a common playback signal processing circuit. Therefore, there is a problem in that advance playback and simultaneous playback cannot be performed at the same time.

Further, if dedicated reproduction signal processing circuits are provided for each of advance reproduction and simultaneous reproduction, it is possible to perform advance reproduction and simultaneous reproduction simultaneously, but the overall circuit scale becomes extremely large.

(Problems to be Solved by the Invention) As described above, the conventional VTR is equipped with a preceding playback head and a simultaneous playback head and is capable of editing PCM audio signals.
However, it is not possible to perform advance playback and simultaneous playback at the same time, and if a dedicated playback signal processing circuit is provided for advance playback and simultaneous playback to enable simultaneous playback, the overall circuit scale will increase. There was a problem.

An object of the present invention is to provide a rotary head type magnetic recording/reproducing apparatus which can perform simultaneous reproduction while performing advance reproduction except in some cases, without substantially increasing the circuit scale.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a reproduction signal processing means for processing N-channel reproduction PCM audio signals. Channel playback PCM
a first mode for providing an audio signal and a second mode for providing an N-channel playback PCM audio signal from a pre-play head;
In addition to the above mode, the reproduced PCM audio signals of selected M channels (M is an integer satisfying 1≦M≦N-1) out of the N channels of reproduced PCM audio signals from the simultaneous playback heads and the reproduced PCM audio signals from the preceding playback head. N-channel playback PCM
By providing a switching means having a third mode for simultaneously supplying the reproduced PCM audio signals of selected (N-M) channels of the audio signals, the reproduction that is supplied from the simultaneous reproduction head and the preceding reproduction head, respectively. While using a reproduction signal processing circuit for N channels, which is the same as the number of channels of the PCM audio signal, simultaneous reproduction of M channels and (N-
M) Preliminary playback of channels can be performed simultaneously.

Further, the present invention further includes a second switching means that operates in conjunction with the switching means (referred to as the first switching means),
The N-channel processed output signal from the playback signal processing means is divided into a signal based on the playback PCM audio signal from the simultaneous playback head and a signal based on the playback PCM audio signal from the preceding playback head, and distributed to separate output terminals. It was designed to do so.

(Function) In the present invention, a part of the PCM audio signal from the simultaneous reproduction head, By adding a third mode that simultaneously supplies part of the PCM audio signal from the advance playback head to the playback signal processing means, it is possible to simultaneously perform advance playback without increasing the circuit scale of the playback signal processing means. It also becomes possible to perform playback. As a result, for example, a channel that is a source during audio editing can be played back in advance, and a channel that is to be re-recorded (which may be the same as or different from the source channel) can be played back simultaneously.

Furthermore, if the second switching means is added after the playback signal processing means, the signal obtained by processing the PCM audio signal from the simultaneous playback head and the PCM sound from the preceding playback head can be output regardless of the mode of the first switching means. Since the processed signals and the signals are respectively taken out from separate output terminals, handling of the apparatus becomes easier.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows a VT as explained in FIGS. 5 and 6.
The configuration of a PCM audio signal reproducing circuit according to an embodiment applied to R is shown. Further, FIG. 2 shows the configuration of a PCM audio signal recording circuit in this embodiment. In this embodiment, two audio channels are treated as a unit and are referred to as follows.

Audio channel 2-channel A Audio channels 3 and 4 - Channel B First, the configuration of the recording port will be explained with reference to FIG.

P of both channels A and B entering input terminals 21a and 21b
The CM audio signal is sent to the error correction encoding circuit 22a.

22b, the data is encoded for error correction and data shuffled (rearranged) in units of one field, and then subjected to channel coding by modulation circuits 23a and 23b. Modulation circuits 23a, 23
The output of signal b is subjected to head switching and multiplexing with the video signal by switching circuits 24a and 24b, and is further sent to the recording amplifier 2.
5, the A channel signal is sent to the recording head R.
Using AI and RA2, the B channel signal is recorded on the tape by recording heads RBI and RB2, respectively.

Next, the configuration of the reproducing circuit will be explained with reference to FIG.

First, the A channel and B channel signals on the tape are reproduced by the simultaneous reproduction heads CPAI, CPA2 and CPBI, CPB2, respectively, and the reproduction amplifier 1
After being amplified by the switching circuits 3a and 3b, the PCM audio signal and the video signal are separated at predetermined head switching timing, and the signals of CPAI and CPA2 and the signals of CPBI and CPB2 are multiplexed, respectively, and the signals of CPAI and CPA2 are multiplexed.
A. It becomes CPB.

CPA and CPB are simultaneously reproduced PCM audio signals (RF multiplied signals) of channels A and B, respectively.The video signals separated by the switching circuit 3 are guided to a video processing circuit (not shown).

The A channel and B channel signals on the tape are sent to the advance playback heads APAI, APA2 and APB respectively.
After being regenerated by APR2 and amplified by regenerative amplifier 2, switching circuits 4a and 4b select APAI and APR2.
The signals of PA2, APBI, and APR2 are multiplexed, respectively, to become APA and APR.

APA and APR are advance reproduction PCM audio signals of channels A and B, respectively.

The signals APA, APB and CPA, CPB are guided to a reproduction mode switching circuit 5, which is a first switching means based on the present invention. As will be explained in detail later, this reproduction mode switching circuit 5 selects two systems of PCM audio signals (RF multiplied signals) and supplies them to reproduction signal processing circuits 6a and 6b of N channels (N-2 in this embodiment). The reproduced signal processing circuit 6a is a data reproducing circuit 7a and an error correction circuit 8a.
and an error correction circuit 9a, and the reproduction signal processing circuit 6b is also a data reproduction circuit 7b.

It is composed of an error correction circuit 8b and an error correction circuit 9b. Data reproducing circuits 7a and 7b perform waveform equalization, clock extraction, data identification, frame synchronization, and demodulation. Error correction circuit 3a.

In step 8b, data errors occurring during the recording/reproducing process are corrected based on the error correction and correct codes generated on the recording side, and an operation called deshuffling is performed to return the data to the original order. The error correction circuits 9a and 9b perform processes such as average value interpolation and previous value retention on data that could not be corrected by the preceding error correction circuits 8a and 8b to prevent abnormal noise from occurring.

In this way, two systems of PCM audio signals are transmitted to the playback signal processing circuit 6.
The signals are output from terminals a and 6b, converted into analog signals by D/A conversion as necessary, and then guided to output terminals 10a and 10b.

The reproduction mode switching circuit 5 is ■APA, ■CPA.

(2) A changeover switch 5a that supplies one signal of CPB to the reproduced signal processing circuit 6a, and (2) APB.

It consists of a changeover switch 5b that supplies one of the signals ①CPR and ⑥CPA to the reproduced signal processing circuit 6b. The changeover switches 5a and 5b can be switched independently by a reproduction mode control signal, and can take a total of nine combinations of states.

First, normally the changeover switch 5a is
b is in the first mode connected to (2), respectively, and when all channels are simultaneously reproduced (or normal reproduction), the simultaneously reproduced signals CPA and CPB of both channels A and B are output to the reproduced signal processing circuit 6a.

6b.

Next, during advance playback of all channels, the selector switch 5a
, 5b are connected to ■ and ■, respectively, in the second mode, and the advance playback signals APA and APB of both channels A and B are
are supplied to reproduction signal processing circuits 6a and 6b, respectively.

The output signals of the playback signal processing circuits 6a and 6b during this advance playback are subjected to the editing processing described above (for example, mixing with other signals, mixing between channels, fade-in/fade-out, filter processing, etc.). After that, re-recording is performed. However, simultaneous playback is not possible during this advance playback. Incidentally, in conventional VTRs, there is a combination of the states of the changeover switches 5a and 5b.

There are only two types, ■-■ and ■-■, as described above.

Here, if we consider the case where the third option based on the present invention, for example -■, is selected as the combination of states of the changeover switches 5a and 5b, the advance playback signal AP of the A channel
While reproducing A by the reproduction signal processing circuit 6a,
The processed signal of the output audio signal of the channel is sent back to B.
An editing mode is adopted in which the B channel simultaneous playback signal CPB recorded in the channel and immediately played back by the simultaneous playback head is played back by the playback signal processing circuit 6b, and the edited B channel audio signal is immediately monitored. becomes possible. Similarly, the editing functions shown in the following table can be realized by combining the states of the changeover switches 5a and 5b in the third mode.

That is, under the constraint that one of the A and B channels is used as a source for editing and one of the A and B channels is rewritten, the M channel (in this example, the M
-1) and advance reproduction of N-M channels (NM-1 in this embodiment) can be realized simultaneously. In the case of this embodiment, since each of the A and B channels includes two channels of audio signals, it is thought that even with such restrictions, a considerable portion of the audio editing work can be covered. Of course, if the selector switches 5a and 5b are set to ■-■ as mentioned above, A and B
Editing using both channels as sources (however, simultaneous playback is not possible) is still possible as before.

FIG. 3 shows the playback mode switching circuit 5 in the embodiment shown in FIG.
This figure schematically shows the timing of recording and reproduction when the combination of states of the changeover switches 5a and 5b is set to ■-■. This is a case where the A channel is previously reproduced, processed, rerecorded, and simultaneously monitored. First, the A channel advance playback head A P Al, which is arranged to scan the track 3.5 fields ahead of the A channel recording RAI and RA2, respectively.
The signal APA reproduced by APA2 undergoes processing such as error correction in the reproduced signal processing circuit 6a in the next field, and then is output in the next field. The signal processed by mixing this output audio signal with other input signals becomes the input for recording the A channel again, and in the next field it is subjected to error correction encoding etc. in the recording circuit shown in Figure 2. Then, in the next field, the A channel recording head RAt.

Recorded by RA2. The recorded A channel signal is sent to the A channel simultaneous playback head CPAI.

Immediately after (after 114 fields) the signal is reproduced by the CPA 2, error correction and the like are performed in the reproduction signal processing circuit 6b in the next field, and output in the next field.

The above-described signal flow is indicated by diagonal lines in FIG. 3 for one field of signals. However, the monitor output in this case is output as a B channel signal, so
In order to further improve usability, it is preferable to also switch the subsequent interface circuit so that this is outputted from the VTR as a simultaneous playback output of the A channel.

As shown in Figures 3 and 6, the preceding playback head and the simultaneous playback head are mounted on the rotating drum at different phases, so when outputting audio in field units, this time difference must be compensated for in the playback circuit. It is necessary to compensate. The time chart in Figure 3 shows the case where a buffer is provided before the error correction circuit to absorb this time difference, but of course the amount of delay at the stage after the error correction circuit or the stage after the error correction circuit is determined by the reproduction mode control signal. It may be possible to switch depending on the situation. In any case, since compensation for such time differences is necessary even in conventional VTRs, implementation of the present invention does not increase the scale of the reproduced signal processing circuit.

As described above, according to the embodiment shown in FIG. 1, audio channel 2 and audio channels 3 and 4 can be processed as units without losing any of the functions of a conventional VTR or increasing the scale of the reproduction signal processing circuit. When editing audio, advance playback and simultaneous playback can be performed at the same time, except in some cases.

Next, another effect of the configuration of this embodiment will be explained. First, when it is necessary to reproduce only one of the A and B channels during normal playback or simultaneous playback, the playback mode switching circuit 5 is set to the fourth mode, for example, with the changeover switch 5a,
By setting the combination of states of 5b to ■-■ (or ■-■), the same simultaneous playback PCM audio signal CPA
(or CPB) are two reproduction signal processing circuits 6a, 6
b. Here, for example, if the coefficients of the waveform equalization filter and the algorithms of the frame synchronization circuit, error correction circuit, and error correction circuit are made different between the reproduction signal processing circuits 6a and 6b only in this reproduction mode, the reproduction Different outputs are obtained from the signal processing circuits 5a and 6b. By comparing these two outputs, we select the most reliable data from the A channel (or B channel).
This makes it possible to output the following. In particular, different error correction algorithms are effective in preventing errors from being overlooked.

Next, as an example of the fourth mode, selector switch 5a
, 5b is ■-■, compared to the case of ■-■, the reproduction signal processing circuits 6a and 6b are exchanged to perform normal reproduction or simultaneous reproduction.
In the unlikely event that there is an abnormality in the output of either the channel or the B channel, selecting this reproduction mode can be expected to have the secondary effect of being able to diagnose whether or not there is a failure on the reproduced signal processing circuit side.

When actually selecting the 1st to 4th modes mentioned above, the frequently used modes can be set easily, and the user does not have to be conscious of switching connections inside the VTR. , it is desirable to take into consideration operability.

FIG. 4 shows another embodiment of the present invention focusing on this point, and reproduced signal processing circuits 6a and 6b in the embodiment of FIG.
Output terminal switching circuit 1 as a second switching means on the output side of
1 is added.

This output terminal switching circuit 11 includes playback signal processing circuits 6a and 6.
b output terminal and normal/simultaneous playback output terminals 12a, 12b
and advance playback output terminal 13a.

two changeover switches 11a connected between the
These changeover switches 11a, llb
is a changeover switch 5a in the reproduction signal switching circuit 5 according to the reproduction mode control signal.

It is switched in conjunction with the changeover switches 5a and 5b so as to take the same combination of states as 5b. However, among the combinations of states of changeover switches lla and llb, ■-■ and ■-
(2) shows the reproduction signal processing circuit 6a.

Since the re-output terminal 6b will be connected to the normal/simultaneous reproduction output terminal 12b or 12a at the same time, these combinations are prohibited, and the changeover switch 5a of the reproduction signal switching circuit 5
, 5b when the combination of states is ■-■ and ■-■,
For example, the combination of states of the changeover switches 11, a, and llb is set to -■.

According to this embodiment, no matter which of the first to fourth modes the reproduction signal processing circuit 5 takes, the simultaneous reproduction head CP At
, CP A2. CP B1. Signals based on the PCM audio signals CPA and CPB from CP B2 are output to normal/simultaneous playback output terminals 12a and 12b, and are also output to advance playback heads APAI, APA2. A.P.B.I.

Signals based on the reproduced PCM signals APA and APB from APR2 are output to advance reproduction output terminals 13a and 13b.

Therefore, the user of the VTR of this embodiment has two output terminals 10a as in the embodiment of FIG.

The normal/simultaneous playback signal output and the advance playback signal output are output to each of the channels 10b, and there is no need to think about whether the A channel or the B channel is being output, which improves the operability during editing. Significantly improved.

This invention is not limited to the embodiments described above, and various modifications are possible. For example, the editing units of PCM audio channels can be subdivided so that the playback mode can be switched for each channel.For example, channels 2 and 3 can be played back in advance and the mixed signal can be recorded on channel 4 and monitored. Good too. In that case, since the error correction/compensation circuit originally only has the processing capacity for 4 channels (more generally, N channels), the difference between the number of channels to be played simultaneously (M) and the number of channels to be played in advance is still M+. A relationship of ≦N is required.

Further, during normal reproduction, a recording/reproducing head may be used instead of a simultaneous reproduction head. Furthermore, since the error correction circuit has the largest circuit scale in the reproduction signal processing circuit, the intended purpose of the present invention can be achieved even if the reproduction mode switching circuit is provided anywhere between the reproduction amplifier and the error correction circuit. can be achieved.

[Effects of the Invention] According to the present invention, the first mode supplies only the reproduced PCM audio signal from the simultaneous reproduction head to the reproduced signal processing means that processes the reproduced PCM audio signals of N channels, and Apart from the second mode, which provides only the reproduced PCM audio signal from the head, the N
The reproduced PCM audio signals of M channels (M is an integer satisfying 1≦M≦N-1) among the reproduced PCM audio signals of the channels and the reproduced PCM of N channels from the preceding playback head.
By providing the first switching means having a third mode that simultaneously supplies the reproduced PCM audio signal of (N-M) channels of the audio signal, it is possible to eliminate the need to increase the circuit scale of the reproduced signal processing means. Simultaneous reproduction of M channels and advance reproduction of (NM) channels can be performed simultaneously. Therefore, when editing PCM audio, only the source channel can be played back in advance, and the channels to be re-recorded can be played back at the same time, making it possible to perform the editing work more reliably and easily.

Furthermore, according to the present invention, a second switching means that operates in conjunction with the first switching means is added, so that the N-channel processed output signal from the reproduction signal processing means is converted into a reproduction PCM audio signal from the simultaneous reproduction head. By dividing the signal based on the PCM audio signal from the preceding playback head and the signal based on the reproduced PCM audio signal from the preceding playback head and distributing them to dedicated output terminals, the user can
There is no need to be aware of the states of the first and second switching means inside the TR, and the device can be easily handled.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a PCM audio signal reproducing circuit in an embodiment of the present invention, Fig. 2 is a block diagram of a PCM audio signal recording circuit in the same embodiment, and Fig. 3 explains the operation of the embodiment. FIG. 4 is a block diagram of a PCM audio signal reproducing circuit according to another embodiment of the present invention, FIG. 5 is a diagram showing the track format on the tape, and FIG. 6 is a diagram showing the track format on the rotating drum. FIG. 1.2-...Regenerative amplifier, 3a, 3b, 4a, 4b...
- Switching circuit, 5... Playback mode switching circuit (first switching means), 6a, 6b... Playback signal processing circuit, 10a,
10b...Output terminal, 11...Output terminal switching circuit (
2nd switching means), 12a, 12b... Normal/simultaneous playback output terminal, 13a, 13b... Advance playback output terminal, 51a, 51b... Video signal recording area, 52a~
52d... PCM audio signal recording area, RAl, R
BI, RA2. RB2...To the record, Sodo, E A
t. E B1. E A2. E B2... To rotation erasure, Sodo, CP At. CP B1. CP A2. CP B2... Simultaneous playback head, APAl, APBI, APA2.
APB2... Advance playback head. Applicant's agent Patent attorney Takehiko Suzue 1 <L<ζ

Claims (2)

[Claims] (1) A recording head that records N channels (N is an integer of 2 or more) of PCM audio signals, a simultaneous playback head that is arranged to scan tracks at a position behind these recording heads, and a preceding playback head arranged to scan a track at a preceding position; a playback signal processing means for processing N channels of playback PCM audio signals; a first mode for providing N channels of played PCM audio signals from the preceding playhead, and a second mode for providing N channels of played PCM audio signals from the simultaneous playheads. selected M channels (M is an integer satisfying 1≦M≦N-1) of the reproduced PCM audio signals and selected (N-M) channels of the N-channel reproduced PCM signals from the preceding playback head. A rotary head type magnetic recording and reproducing apparatus comprising a switching means having a third mode for simultaneously supplying a reproduced PCM audio signal and a reproduced PCM audio signal. (2) A recording head that records N channels (N is an integer of 2 or more) of PCM audio signals, a simultaneous playback head that is arranged to scan tracks at a position behind these recording heads, and a preceding playback head arranged to scan a track at a preceding position; a playback signal processing means for processing N channels of playback PCM audio signals; a first mode for providing N channels of played PCM audio signals from the preceding playhead, and a second mode for providing N channels of played PCM audio signals from the simultaneous playheads. (N-M) of the selected M channels (M is an integer satisfying 1≦M≦N-1) of the reproduced PCM audio signals and the N-channel reproduced PCM audio signals from the preceding playback head. a first switching means having a third mode for simultaneously supplying a reproduced PCM audio signal of the channel; and a processed output of the N channels from the reproduced signal processing means, which operates in conjunction with the first switching means. and second switching means for dividing the signal into a signal based on the reproduced PCM audio signal from the simultaneous reproduction head and a signal based on the reproduced PCM audio signal from the preceding reproduction head and distributing the signals to separate output terminals. A rotating head type magnetic recording and reproducing device.