JPS61175969A - Signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To eliminate a noise caused by the signal lack of drop-out, head switching, etc., by recording plural signals by providing a prescribed time difference to each other, executing the time matching of plural signals which are reproduced, and replacing a lacking part with other signal when the plural signals are lacked. CONSTITUTION:The FM sound signal of a right side signal is delayed by a delaying circuit 17 and becomes as shown by figure C. In a drop-out part in which envelope levels of parts R3-R6 of a signal shown by figure C are shown by zero,a switch 20 fetches a signal from a terminal (b), therefore, the sound signal of figure D is fetched from a terminal 24 connected to the movable contact piece of the switch 20. In the same way, the sound signal of figure E is fetched from a terminal 25. In figures D, E, parts r1-r6 show the right side signal which demodulate the FM sound signals of parts R1R6, and parts l1-l6 show a left side signals which demodulate the FM sound signal of parts L1-L6. The right side signal and the left side signal whose time positions correspond to each other have the correlation of some extent, therefore, can be compensated by replacing the drop-out part of the right (left) side signal with the left (right) signal of the same time position.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a signal recording and reproducing device, which records on a recording medium,
The present invention relates to a signal recording and reproducing apparatus that compensates for and outputs a signal that is subsequently reproduced when the signal is deleted.

BACKGROUND ART When recording and reproducing signals using a magnetic tape, dropouts of reproduced signals due to scratches, bends, etc. of the magnetic tape cannot be avoided.

If the signal recorded on the magnetic tape is a video signal, assuming that the line correlation of the video signal is high and the dropout is short, if there is a dropout in the reproduced video signal, the Conventionally, interpolation is performed using video signals of .

Problems to be Solved by the Invention Regarding audio signals, there is no correlation between the preceding and succeeding periods of a single signal as there is with video signals. For this reason, in conventional signal recording and reproducing devices such as so-called high-fidelity video tape recorders, which record FM audio signals on tracks inclined in the longitudinal direction of a magnetic tape in the same way as video signals, dropouts occur in the reproduced audio signals. If this occurs, the level immediately before the dropout of the audio signal is maintained and continues to the level immediately after the dropout, thereby compensating for the dropout of the audio signal. The same applies to compensation for head switching noise that occurs when two audio heads provided on a rotary cylinder are sequentially switched during playback. Therefore, there is a problem in that noise caused by signal loss due to dropouts, head switching, etc. cannot be completely removed.

Therefore, the present invention solves the above problems by recording mutually correlated signals with a predetermined time difference, aligning the time of the reproduced signals, and replacing the deleted portions of each signal with other signals. The purpose of the present invention is to provide a signal recording/reproducing device that solves the above problems.

Means for Solving the Problems In the apparatus of the present invention, a plurality of signals are recorded with a predetermined time difference from each other, and the reproduced signals are time-synchronized, so that when each of the plurality of signals is missing, the signal is detected. Replace the excluded part with another signal.

In the device of the present invention, a plurality of signals having a high correlation with each other are recorded on a recording medium with a predetermined time difference, and the reproduced signals are time-aligned, and when each of the plurality of signals is missing, Replace the missing part with another signal. The signal deletion that occurs when reproducing multiple signals from the recording medium described above is caused by the multiple signals being recorded at different time positions because the multiple signals are recorded with a predetermined time difference, and due to the above time alignment. It becomes possible to replace the deleted portions of each of the plurality of signals with other signals.

Embodiment FIG. 1 shows a block system diagram of a first embodiment of the apparatus of the present invention. In the figure, the right side signal of the audio stereo signal comes into terminal 1, and the left side signal comes into terminal 2. The right signal is F
M modulator 3, where the carrier frequency is 1.3, for example.
The signal is converted into a MHZ FM audio signal and supplied to the mixing circuit 4. In addition, the left side signal is sent to the delay circuit 5, for example, from several H to several 10
After being delayed by a predetermined time τ1, which is the value of H, the signal is supplied to the FM modulator 6, where it is converted into an FM audio signal with a carrier frequency of 1.7 MH2, for example, and supplied to the mixing circuit 4.

The FM audio signals of the right side signal and the left side signal mixed in the mixing circuit 4 are sent to the audio head 9 and 10 attached to the rotary cylinder 8 via switches 7a and 7b, respectively, whose movable contacts are connected to the R terminal during recording. provided to each. As a result, as shown in FIG. 2, mixed FM audio signals are sequentially recorded from the lower end to the upper end of each of the tracks T1 to T6, which are inclined in the longitudinal direction of the magnetic tape 11. Here, for example, tracks T+, T3, and Ts are each tracked by the audio head 9.
The tracks T2, T4, and T6 were recorded by the audio head 10, respectively. Incidentally, a video signal from a video signal recording circuit (not shown) is supplied to the video heads 12 and 13 attached to the rotary path cylinder 8, and the video signal is recorded over the tracks T1 to T6 of the magnetic tape 11. However, since the recording wavelength of the mixed FM audio signal is relatively long and it is recorded deep into the magnetic tape 11 at a saturation level, and the video signal is recorded at a high frequency on the surface layer of the magnetic tape 11, the mixed FM audio signal is It will not be erased by recording the signal.

During reproduction, the movable contacts of the switches 7a and 7b are connected to the terminal P, and the mixed FM audio signal reproduced by the audio heads 9 and 10 is supplied to the terminals a and b of the switch 7C, respectively. The switching pulse generation circuit 14 generates a head switching pulse from the rotation detection pulse of the rotary cylinder 8, and supplies it to the switch 7C. The mixed FM audio signal taken out from the movable contact piece of this switch 7C is supplied to bandpass filters 15 and 16, respectively. The bandpass filter 15 passes signals around a frequency of 1.3 MHz,
The FM audio signal of the right side signal obtained here is sent to the delay circuit 17.
After being delayed by a predetermined time τ1, the signal is supplied to the dropout detection circuit 18 and the FMII adjuster 19. The dropout detection circuit 18 generates, for example, an H level switching signal and supplies it to the control terminal of the switch 20 when the peak level of the supplied right-side FM audio signal is attenuated by about 20 dB from normal. The FM demodulator 19 demodulates the FM audio signal to obtain the right side signal, which is sent to the switch 20.
．． 21 to each terminal a.

Furthermore, the bandpass filter 16 is for passing signals around a frequency of 1.7 MHz, and the left side FM audio signal obtained here is supplied to an FM demodulator 22 and a dropout detection circuit 23, respectively.

The FM demodulator 22 demodulates the FM audio signal and supplies the left side signal to the terminals of the switches 20 and 21, respectively. The dropout detection circuit 23 generates an H level switching signal and supplies it to the control terminal of the switch 21 when the peak level of the left side FM audio signal is attenuated by 20 dB or more from normal. The switching signal of the switch circuit 20 is L.
- When the switching signal is at the L level, the signal that enters the terminal a is taken out, and when the switching signal is at the H level, the signal that comes into the terminal is taken out.The switch circuit 21 takes out the signal that comes into the terminal when the switching signal is at the L level. This is to take out the signal that enters terminal a when it is at H level.

Here, if the magnetic tape 11 is bent and it becomes impossible to reproduce the satin-finished portion surrounded by the dashed line in FIG. The result is as shown in FIGS. 3(A) and 3(B), respectively. Parts R1-R6 in FIG. 3(A) are the FM audio signals of the right side signals reproduced from the lower tracks 1 to T6, respectively, and parts L1-L6 in FIG. This is the FM audio signal of the left side signal with the content corresponding to . The FM audio signal on the right side above is the delay circuit 1.
7 and is delayed as shown in FIG. 3(C). Parts R3, Ra, Rs of the signal shown in FIG. 3(C)
Since the switch 20 takes out the signal from the terminal at the dropout part where the envelope level of each of , Rs is zero, the sound shown in FIG. 3(D) is output from the terminal 24 connected to the movable contact piece of the switch 20. A signal is extracted. Similarly, the audio signal shown in FIG. 3(E) is taken out from the terminal 25 connected to the movable contact piece of the switch 21. In FIGS. 3(D) and (E), the parts "1 to r6 respectively indicate the right-side signals obtained by demodulating the FM audio signals of the parts R1-R6, respectively, and the parts l+-1s each indicate the FM audio signals of the parts L1 to L6, respectively. This shows the left signal that has been demodulated.Since there is a certain degree of correlation between the right signal and the left signal at corresponding time positions, the dropout part of the right signal (left signal) is compared to the left signal (right signal) at the same time position. ) can compensate for dropouts.

As a result, if the probability of occurrence of a dropout is X, the probability that a dropout will appear in the audio signal taken out from the terminals 24 and 25 is x2, and most dropouts can be compensated for.

As shown by the broken line in FIG. 1, the etch detector 26 detects the rise of the head switching pulse and the rising edge of the etch, generates an H level switching pulse, and supplies this switching pulse to the control terminal of the switch 21. Additionally, the signal may be delayed by a predetermined time τ1 in the delay circuit 27 and then supplied to the control terminal of the switch 20. In this case, even if switching noise occurs due to switching of the switch 7, the switching noise generation portion of the right side signal (left side signal) is replaced by the left side signal (right side signal @) without switching noise, and the switching noise is generated from the terminals 24 and 25, respectively. An audio signal without switching noise is extracted.

Further, the delay circuit 17. The circuit shown in FIG. 6 may be used instead of the dropout detection circuit 18 and the FM demodulator 18. The right-side FM audio signal from the bandpass filter 15 entering the terminal 65 in FIG. 6 is directly supplied to the dropout detection circuit 18 and the FMI adjuster 19, respectively. The switching signal output from the dropout detection circuit 18 is delayed by a predetermined time τ1 in the delay circuit 66, and then supplied from the terminal 67 to the control terminal of the switch 20. Further, the right side signal obtained by the demodulation circuit 19 is delayed by a predetermined time τ1 in a delay circuit 68 and is supplied from a terminal 69 to a terminal a of the switch 20. In this case, since the switching signal is a digital signal, a shift register can be used as the delay circuit 66, and since the delay circuit 68 delays the right side signal (audio signal) with a frequency of 0 to 20kHz, the frequency of 1 to 2M1-
It is possible to use a delay circuit with a narrower band than the delay circuit 17 that delays an FM audio signal of about 1z, which is advantageous in reducing costs.

FIG. 4 shows a block system diagram of a second embodiment of the device of the present invention. In the figure, the same parts as in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted. In FIG. 4, the right side signal is FM modulated by an FM modulator 30, and after being delayed by a predetermined time τ1 by a delay circuit 31, it is FM modulated by an FM modulator 32. The left signal is FM modulated by an FM modulator 33, delayed by a predetermined time τ1 by a delay circuit 34, and then FM modulated by an FM modulator 35. FM modulator 30°32.3
For example, the carrier frequency in 3.35 is /? 1.
IMH2, 1.35MHz, 1.6MHz.

1.85 MH2, and these output FM audio signals are mixed in a mixing circuit 4.

The mixed FM' audio signal taken out from switch 7 during reproduction is supplied to bandpass filters 36-39.

Frequency 1.1M1- extracted from bandpass filter 36
The FM audio signal of the right side signal centered at 1z is delayed by a predetermined time in the delay circuit 40, FM demodulated into a right signal by the FM demodulator 41, and supplied to the terminal a of the switch 20, and the FM audio signal from the bandpass filter 36 is The signal is supplied to a dropout detection circuit 42, where the switching signal obtained when the peak level of the FM audio signal is attenuated by 20 dB or more is delayed by 2 for a predetermined time in a delay circuit 43, and is supplied to the control terminal of the switch 20. Ru. This time τ2 is τ, where τa is the delay time of the dropout detection circuit 42.
2-τ1-τa.

Also, the frequency 1.35 extracted from the bandpass filter 37
The delayed right-side FM audio signal centered at MHz is demodulated by an FM demodulator 44, and the resulting right-side signal is supplied to the terminal of the switch 20. In this case as well, a dropout-compensated audio signal is taken out from the terminal 24 in the same manner as in the circuit shown in the first diagram. In this case, switch 20
Terminal a.

Since the signals supplied to each terminal b are right-side signals, a complete right-side signal is output from terminal 24.

Bandpass filters 38 and 39 each have a frequency of 1.6 MH2゜1
．． The FM audio signals of the left side signals of each of the 85MH7 are extracted, and these FM audio signals of the left side signals are processed by the left side signal processing circuit 45 to perform dropout compensation, and the left side signals are outputted from the terminal 25. The left signal processing circuit 45 includes a delay circuit 40 that performs ffi processing on the right signal.
- FM with approximately the same configuration as the FM demodulator 44 and switch 20
v! The frequencies used by the I modulators are different.

FIG. 5 shows a block diagram of a third embodiment of the circuit of the present invention. In this figure, the same parts as in FIG. 4 are given the same reference numerals, and their explanations will be omitted. In FIG. 5, the delay time τ3 of the delay circuit 50 is approximately twice the delay time τ1 of the delay circuit 34. The right-side FM audio signal taken out from the reproduced bandpass filter 36 is delayed by a predetermined time τ3 in a delay circuit 51, and then demodulated into a right-side signal in an FM demodulator 41 and supplied to terminal a of the switch 20. Ru.

Further, the signal from the delay circuit 51 is supplied to the dropout detection circuit 42, and the switching pulse obtained here is supplied to the control terminal of the switch 20. Further, the FM audio signal, which is the delayed right signal from the bandpass filter 37, is demodulated by the FM demodulator 44 and supplied to the terminal of the switch 20, and is also supplied to the dropout detection circuit 52, where the FM audio signal is An H level switching signal obtained when the peak level of is attenuated by 20 dB or more is supplied to an AND circuit 53. The AND circuit 53 performs a logical product of the switching signals of the dropout detection circuits 42 and 52 to generate a new switching signal and supplies it to the control terminal of the switch 54.

Further, the right side signal taken out from the switch 20 is supplied to the terminal a of the switch 54.

The reproduction processing for the left side signal is also similar to that for the right side signal.

The left side FM audio signal extracted from the bandpass filter 38 is delayed by 1 for a predetermined time in a delay circuit 55. After that, it is demodulated by the FM demodulator 56 and the terminal a of the switch 21 is
and the terminal of the switch 54, and the switching signal obtained by being supplied to the dropout detection circuit 57 is supplied to the control terminal of the switch 21 and the AND circuit 5.
8. The delayed left side FM signal from the bandpass filter 39 is demodulated by the FM demodulator 59 and supplied to the terminal of the switch 21, and is also supplied to the dropout detection circuit 60, where the switching signal obtained is sent to the AND circuit. 58.

The AND circuit 58 ANDs the switching signals from the dropout detection circuits 57 and 60 to generate a new switching signal and supplies it to the llj control terminal of the switch 61. The terminal of the switch 61 is connected to the FM demodulator 41.
The right side signal is being supplied.

Here, the switch 20 takes out the right side signal from the FM demodulator 41 when there is no dropout in the right side signal from the FM demodulator 41, and takes out the right side signal from the FM demodulator 44 when there is a dropout. to compensate for dropout. The right side signal obtained in this way is normally taken out from the switch 54,
Furthermore, if there is a dropout in the right side signals from each of the FM demodulators 41 and 44, the above right side signals are sent to the FM demodulator 56.
is replaced and compensated by the left-hand signal of Similarly, from switch 61, when there is no dropout, F
The left side signal from the M demodulator 56 is taken out, and if there is a dropout in this, the left side signal from the FM demodulator 59 is taken out, and if there is a dropout in both of the left side signals, the left side signal from the FMI modulator 41 is taken out. The right side signal is taken out to compensate for dropouts. In this case, if the probability of occurrence of dropout is X, then terminal 24.
The probability that a dropout will appear in the audio signal extracted from each of the 25 is x3.

Note that the devices shown in FIGS. 4 and 5 are also provided with an etch detector and a delay circuit in the same way as the device shown in FIG. It goes without saying that a configuration may be used to remove head switching noise, and a circuit as shown in FIG. 6 can be used.

The present invention is suitable for application to, for example, a high-fidelity video tape recorder that records audio signals sequentially on tracks inclined in the longitudinal direction of a magnetic tape, but is not limited to this. A recording/playback device that records stereo audio signals, or two devices that are correlated with each other.
The present invention may be applied to a recording/reproducing device that records channel signals, and is not limited to the above embodiment.

Effects of the Invention As described above, even if a signal reproduced from a recording medium is deleted, the signal recording and reproducing apparatus according to the present invention can recover the time during which the signal was deleted in each of the plurality of signals separated from the reproduced signal. Since the positions are different, the missing parts of each of the plurality of signals can be replaced and compensated for with other signals having a high correlation,
The probability that the effect of dropout will appear on each of the multiple signals that are played back and output can be sufficiently reduced, resulting in dropout.

It has the advantage of being able to almost eliminate noise caused by head switching.

[Brief explanation of the drawing]

1, 4, and 5 are block diagrams of each embodiment of the device of the present invention, and FIG. 2 is a diagram showing a track pattern of an embodiment of the signal recorded by the device of the present invention. FIG. 3 is a diagram for explaining signals reproduced by the device shown in FIG. 1, and FIG. 6 is a circuit configuration diagram of a partial modification of the device shown in FIG. 3.6, 30.32, 33.35...FM modulator, 5
．． 17.31,34,40.43.51.55゜66.
68...Delay circuit, 4...Mixing circuit, 7a-7c
, 20, 21, 54.61... switch, 9°10.
...Audio head, 15.16.36-38...Band filter, 18.23.42,52,57゜60...Dropout detection circuit, 19.22゜41.44.56
．． 59...FM demodulator.

Claims (3)

[Claims] (1) At the time of recording, at least one signal among a plurality of signals having a high correlation with each other is delayed so that the plurality of signals have a predetermined time difference from each other, and the plurality of signals are set to have a frequency band. dividing and multiplexing and recording on a recording medium, and at the time of reproduction, delaying at least one signal that has not been delayed during recording among the plurality of signals reproduced and separated from the recording medium, and aligning the time of the plurality of signals; A signal recording and reproducing apparatus characterized in that, when a deletion of a part of each of the plurality of signals is detected, the deletion part is replaced with another signal to compensate. (2) The signal recording and reproducing apparatus according to claim 1, wherein the plurality of signals are the same signal. (3) The signal recording and reproducing apparatus according to claim 1, wherein the plurality of signals are a right side signal and a left side signal of an audio stereo signal.