JPS59210509A - Digital signal recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital signal recording and reproducing device such as a PCM recording and reproducing device, and an object of the present invention is to record and reproduce a recorded tape regardless of whether the tape runs in the forward or reverse direction. , the synchronization signal is detected, and by detecting the direction detection signal that is recorded along with the synchronization signal, it is possible to detect whether the running direction is forward or reverse, and to display this to the operator, and to load the tape. It notifies you whether the direction is correct or not, and if the direction of travel is reversed, the processing circuit for the reproduced digital signal is switched so that the analog original signal can be obtained whether the direction of travel is forward or reverse, allowing accurate cueing operations. The aim is to improve operability as much as possible.

In conventional PCM recording and playback devices, it is difficult to detect a synchronization signal in order to restore the reproduced digital signal played from a recorded tape to an analog original signal, but conventional synchronization signals can be used in any pattern arrangement. Moreover, since the pattern was asymmetrical with respect to the center, if the running direction was reversed when playing back a recorded tape, it would be impossible to detect the synchronization signal and the original sound could not be reproduced. .

If a synchronization signal could not be detected, muting was normally applied, and nothing was output as a line output.

For this reason, if the tape is installed in the wrong direction, line output will not be obtained, and the operator must determine whether the cause is that the tape was not recorded correctly or a malfunction in the installation.
It was not easy to determine whether the tape was attached in the opposite direction.

However, unlike analog recording and playback devices, conventional PCM recording and playback devices cannot run the tape in the opposite direction for playback, making it difficult to accurately locate the beginning of the tape when editing or recording. The cue is found by repeating a series of fast-forward, two-reverse, and playback operations.

SUMMARY OF THE INVENTION The present invention is intended to eliminate these and other drawbacks of the prior art, and one embodiment thereof will be described below with reference to Figures if+i.

FIG. 1 shows an example of a synchronization signal pattern produced by the apparatus of this embodiment. In this example, a pattern section symmetrical with respect to the center position a of the pattern is provided, and one bit of the tape running direction detection signal C9d is arranged before and after this section. It goes without saying that the traveling direction signals c and d are also symmetrical with respect to the center position C.

Next, in FIG. 2, the reproduced digital signal of the recorded tape containing the synchronization signal, in other words, the reproduced data signal A
is input to the input terminal of the shift register 1, and the tape reproduction clock signal B is input to the clock terminal CP of the shift register 1.

The reproduced data signal A is converted from a serial signal to a parallel reproduced data signal C, which is a parallel signal, at the clock timing of the reproduced clock signal B.
and is input to the digital comparator 3.

A symmetrical code signal, which is a symmetrical part of the synchronizing signal shown in FIG.
Ru. As a result of comparing the above three signals, the digital comparator 2 outputs a comparison detection signal E of L level if the three signals do not match, and H level if they match.
It is input to the D circuit 4.

On the other hand, for the counter voice, the input to the clock terminal CP is J.
'L' reproduced clock signal B is counted, and its output F is input to the NAND circuit 6. The count outputs F are outputted in a matrix in which they all become H level only when the number of clock pulses equal to or slightly less than the number of clock pulses within the period in which the synchronization signal is repeated is counted. When a certain predetermined number of counts ends and all non-count outputs F become H level, NA? i' The D circuit 6 outputs an L level signal, and the count hold terminal CE of the counter 5
P is manually operated to stop the operation of the counter 5.

At the same time, the output of the NAND1 circuit 6 is inverted by the inverting circuit element to become H level, and this H level signal is input to the NAND1 path 4.

Therefore, the comparison detection signal E also detects the synchronization signal and becomes H.
If it is, the synchronous output signal G of the NAND circuit 4 and the L level is sent to the reset terminal RESET of the counter 6.
is input to reset the counter 5 and start counting the reproduced clock signal B.

By the above-mentioned second operation, the synchronization signal can be extracted from the reproduced data signal A, and since the temporally symmetrical parts of the synchronization signal are detected, the synchronization signal can be obtained even if the tape playback direction is reversed. It is possible to detect

Furthermore, when the digital comparator 2 detects the synchronization signal, the digital comparator 3 detects the signal level at the front or rear of the temporally symmetrical part of the synchronization signal, and uses the comparison detection signal H as It is inputted to an AND circuit 8 together with the comparison detection signal from the digital comparator 2, and a running direction detection signal (2) is obtained as its output.

Now, when the time-symmetric part of the synchronization signal enters digital comparator 2, digital comparator 3 receives 1'''.
is input in the normal direction, and if the tape is running in the normal direction, the digital comparator 2 detects the temporally symmetrical part of the synchronization signal and outputs the H level comparison detection signal E. When the digital comparator 3 outputs the input signal "1" and the comparison signal "o"
” is bitten and the relative softness detection signal becomes HiL level, so the output I of the AND circuit 8 goes to L level, and it can be known that the tape is running in the positive direction. If it is in the opposite direction, the digital comparator 3 compares the input signal ``'○'' and the comparison signal ``o'' when the comparison detection signal of the digital comparator 2 reaches H level and 4.h/h. Comparison detection signal H is H
The output of the AND circuit 8 becomes H level, and it is possible to detect that the tape running direction is in the opposite direction.

The output of the AND circuit 8 is input to a display device (not shown) →! By the display of this display device, the user can immediately know whether the four-tape running direction is forward or reverse. Moreover, if the above-mentioned output signal is inputted to a reproduction digital signal processing circuit (not shown), it is possible to detect the case where the tape running direction is the opposite direction.

The processing circuit can be automatically switched to obtain a correct reproduced analog signal.

As explained above, according to the digital signal recording and reproducing device of the present invention, it is possible to detect a synchronization signal regardless of whether the tape running direction is forward or reverse, and at the same time, it is possible to detect a synchronization signal whether the tape running direction is forward or backward. It is also possible to obtain a direction detection signal, so even if the tape is installed in the wrong direction due to an operator's mistake, it is possible to display this fact and have the operator correct the operation. To enable accurate cueing operation by switching a processing circuit for a reproduced digital signal depending on whether the tape is running in the forward or reverse direction so that an analog original signal can be obtained whether the tape is running in the forward or reverse direction. This can greatly improve overall operability.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining an example of a synchronizing signal pattern used in a digital signal recording/reproducing device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a circuit for detecting a synchronizing signal and tape running direction in the same device FIG. 2 is a block diagram for explaining the operation. 1...Nft register, 2...Digital comparator, 3...Digital comparator, 4
...9.・NANDAND circuit・・・Counter, 6
...NANDAND circuit...inversion circuit, 8...
...AND circuit, 8...Reproduction data word, B
... Regenerated clock signal, G ... Synchronous newsletter, ■
...Tape running direction detection signal. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2■

Claims (2)

[Claims] (1) The synchronization signal is recorded on a tape in a symmetrical pattern arrangement with respect to the center position of the signal, and when the tape is played back, the symmetrical part of the synchronization signal is detected and the synchronization signal is extracted. A digital signal recording and reproducing device that can detect synchronization signals regardless of whether the car is running in the forward or reverse direction. (2) Signals of different levels are arranged at symmetrical positions with respect to the center position of the synchronization signal within the symmetrical pattern arrangement of the synchronization signal or before and after the pattern arrangement, and when playing the tape,
2. The digital signal recording and reproducing apparatus according to claim 1, wherein the tape traveling direction can be detected by detecting the signal at the specific level.