JPS589490B2 - Jiki Tape Copy Souchino Copy Level Kensahoshiki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copy level inspection method for a magnetic tape copying device, and when information recorded on a magnetic tape is copied (duplicated) to another unrecorded magnetic tape, multiple By recording a plurality of test signals on a track by switching them with information signals, reproducing the test signals in full width, and comparing the playback level of the test signals for each track with the reference value, the copy level of the copying device can be adjusted. It is an object of the present invention to provide an inspection method that can prevent the production of defective tapes by inspecting the quality before and after recording an information signal to be copied.

In general, duplication is performed by recording the playback signal of a magnetic tape (hereinafter referred to as master tape) on which information to be duplicated is previously recorded, which is reproduced by a single player (hereinafter referred to as master machine), onto an unrecorded magnetic tape. In this case, a plurality of recording machines (hereinafter referred to as slave machines) that perform this duplication are usually prepared and operated in parallel, each receiving a reproduction signal from the master machine and simultaneously making a plurality of copies.

Furthermore, the master tape is a so-called endless tape in which the starting and ending ends are connected in a ring shape, and a mark signal is generally recorded near the joint, and along with the mark signal, the recorded content is faster than the normal tape speed. It is played continuously and repeatedly at dog tape speed.

On the other hand, the plurality of slave machines sequentially record signals of the same content as the repeatedly reproduced master tape onto the unrecorded tape at a tape speed that is lower than the normal speed, similarly to the master machine.

Magnetic tape that has already been recorded (hereinafter referred to as duplicate tape)
are generally cut near the mark signal and individually wound onto reels for each recorded content.

In general, in order to produce good duplicate tapes, the gain and frequency characteristics of the recording amplifier of the slave device must be maintained at appropriate values, and the recording function must not be impaired due to dirt or wear on the recording head. It is necessary to monitor the following:

However, in the past, a partial test was performed to check for defective duplicate tapes after the master machine playback signal had been repeatedly recorded over the entire length of the slave machine's tape.

As a result, the discovery of defective duplicate tapes was delayed, and an opportunity to produce good quality products was lost.

Conventionally, in order to check the recording level of the signal recorded on a duplicate tape, a standard playback machine is calibrated using a standard tape, and the duplicate tape is played back with the calibrated standard playback machine to check the level of the playback signal. That's what I was doing.

However, the level of the above-mentioned playback signal is not constant, including small fluctuations with a relatively short period due to the magnetic material of the tape, etc., and the level decreases due to gain fluctuations of the master device's amplifier, dirt on the head surface, and wear of the tape. Apart from serious causes such as
There was a drawback.

Furthermore, it was not possible to detect the beginning of the causes mentioned above.

The present invention eliminates the above-mentioned drawbacks, and one embodiment thereof will be described below along with the drawings.

FIG. 1 shows a block system diagram of one embodiment of the system of the present invention.

In the figure, reference numeral 1 is a start button, and by pressing this, the relay 2 is turned on, the capstan motor 4 of the master machine 3 rotates, and the master tape (not shown) attached to the master machine 3 is rotated. starts running.

At the same time as the start button 1 is pressed, the delay timer 5 is turned on and the counter 9 is reset.

Here, recording of the program signal by the slave device is started after the tape running speed of the master device 3 reaches a steady speed and after the mark signal is detected by the master device 3.

However, when the master device 3 starts driving, the mark signal on the master tape is at a position immediately after passing the playback head (not shown) of the master device 3, so the slave device is held in an inactive state until the master tape has completed approximately one revolution. It is necessary to do so.

Further, the slave device requires a certain amount of time from the start of driving until it reaches a steady speed, and reproduction level detection, which will be described later, is performed before the master device 3 detects the mark signal.

Therefore, the delay time of the delay timer 5 is set to a time obtained by subtracting the time required for the rise time of the slave unit and the time required for detecting the playback level from the time required for the master tape to run the first round.

When the delay timer 5 is turned on, the relay 6 is turned on, the capstan motor 7 of the slave machine rotates, and the recording tape 8 attached to the slave machine starts running.

On the other hand, when delay timer 5 is turned on, delay timer 1
0 is turned on, and the signal from the delay timer 10 is supplied to the OR circuit 11 together with the signal from the counter 9.

Note that the delay time of the delay timer 10 is set equal to the time required from when the slave machine starts until it reaches a steady speed.

Further, the counter 9 is set to count the number of detected mark signals detected every round of the master tape, and output a signal when counting a predetermined number.

The trigger pulse signal from the OR circuit 11 is sent to the signal distributor 12 and the timer 13 as a trigger signal a as shown in FIG. 2A.
is supplied to turn on the signal distributor 12 and timer 13, respectively.

A signal S as shown in FIG. 2 is taken out from the timer 13 and supplied to the changeover switch 24 and flip-flop 43.

On the other hand, the frequency f respectively extracted from the sine wave oscillator 14
, , f2, f3 are supplied to a signal distributor 12, where these signals are sequentially shifted by a constant time width τ as shown in FIG. distributed as a test signal.

Here, FIG. 3 shows a specific circuit diagram of the signal distributor 12.

In FIG. 3, the signal a as shown in FIG.

This trigger signal a causes the monostable multivibrator 16 to
2 outputs a trigger pulse b as shown in FIG.

The clock pulse generator 17 outputs a clock pulse C having a time width τ from the falling point of the trigger pulse b to the rising point of the adjacent pulse as shown in FIG. 2C, and supplies it to the ring counter 18. .

The ring counter 18 is triggered at each rising edge of the clock pulse C, and pulses g~ as shown in FIGS. 2G~J.
j respectively, and track selection switches S1 to S4 respectively.
supply to.

Switches S1 to S4 are closed by being supplied with signals g to j, respectively.

The pulse g from the ring counter 18 is the pulse g from the ring counter 1.
9 and triggers the ring counter 19 at its rising edge.

Due to this pulse g, as shown in FIG. 2 D to F, the ring counter 19 outputs pulses d to f with a pulse width of 4τ from the time of the trigger, respectively, and the frequency selection switches sA to Sc.
supply to.

Switches SA-Sc are closed by being supplied with signals d-f, respectively.

On the other hand, signals of frequencies f1, f2, and f3 that enter input terminals 20a to 20c from the sine wave oscillator 14 are amplified by buffer amplifiers 21a to 21c, respectively, and then sent to the switches SA.
-SC, where the switches S1-SC are supplied via the switches SA-SC closed by the pulse signals d-f.
It is supplied to S4.

Furthermore, the signals of frequencies f1, f2, f3 are pulse signals g~
K to N in FIG.
The output terminal 2 is amplified into test signals k to n as shown in
3a to 23d.

Note that the clock pulse generator 17 is connected to the ring counter 1.
It is reset and stopped by the fall of the output pulse f at step 9.

The test signal k-n is provided by the selector switch 2 shown in Fig. 1.
4, and is supplied to the recording amplifier 25 for the high level time of the signal S from the timer 13.

The delay time of the timer 13 is set to be longer than the period during which any of the signals g to j is at a high level, that is, 12τ.

Note that the reproduction output of the master device 3 is set to be cut off during this time.

The delay times of these delay timers 5, 10, etc. are set in advance according to the length of the recording tape 8 of the master tape.

The test signal from the recording amplifier 25 is supplied to a 4-channel recording head 26 fixed to the slave device, and as shown in FIG.
The test signals k′1 to n are sequentially shifted by the time width τ.
'3.

Note that the individual recording lengths of the test signals k'1 to n':3 are not limited to the embodiment shown in FIG. There may be.

The test signals k'1 to n'3 recorded on the tape 8 are sequentially reproduced by a full-width reproducing head 27 fixed to the slave machine, and are taken out as a signal 0 as shown in FIG. 5A.

The reproduction signal 0 is amplified and frequency corrected by the reproduction amplifier 28, and the reproduction level is detected by the detector 29.

The signal taken out from the detector 29 has unnecessary components removed by a low-pass filter 30, and is taken out as a signal p having a level as shown in FIG. 5B.

The signal p taken out from the low-pass filter 30 is sent to the comparator 31
and 32, respectively, where potentiometer 3
The levels are compared with the output reference maximum level and the output reference minimum level of Nos. 3 and 34, respectively.

Here, the potentiometer 33 has one end connected to a power supply voltage terminal 35 at a level that is a little higher than the permissible maximum level, and the other end connected to a power supply voltage terminal 36 at a level lower than the permissible minimum level via the potentiometer 34. has been done.

Thereby, the desired reference maximum level and reference minimum level can be obtained by the potentiometers 33 and 34.

The comparator 31 has a low frequency range. Only when the level of the output signal p from the filter 30 is higher than the reference maximum level from the potentiometer 33, the signal is output and supplied to the OR circuit 37.

On the other hand, the comparator 32 outputs a signal and supplies it to the OR circuit 37 only when the level of the output signal p from the low-pass filter 30 is lower than the reference minimum level from the potentiometer 34 .

The OR circuit 37 outputs a signal when the level of the output signal p from the low-pass filter 30 is outside the reference level range,
It is supplied to the AND circuit 38.

On the other hand, the signal distributor 12 outputs a clock pulse similar to the clock pulse C shown in FIG.

The signal q delayed by the delay timer 39 as shown in FIG. 5C is supplied to an AND circuit 38 and a monostable multivibrator 40.

The delay time of the delay timer 39 is shown in FIG. 5B and C.
As shown in FIG. 2, the high level of the pulse signal q is applied to the saturated and stable portions of the level signal p extracted from the low-pass filter 30, excluding the uneven level portions near the rising and falling points in each track T1 to T4. The levels are set to match.

The output signal from the AND circuit 38 is supplied to the shift register 41 at the falling edge of the pulse signal r from the monostable multi-bi break 40, and the output signal is supplied to the shift register 41 at the falling edge of the pulse signal r from the monostable multi-bi break 40.
is turned on to light up the lamps L1 to L12.

By lighting this lamp, defects in the slave device, such as defective gain or frequency characteristics of the recording amplifier 25, can be detected for each track system before the program signal is recorded, thereby preventing the production of defective duplicate tapes. be able to.

Next, by switching the changeover switch 24 when the output signal S of the delay timer 13 becomes low level, the reproduction program signal from the master device 3 is transferred to the recording head 26.
is repeatedly recorded on recording tape 8.

Note that during this period, the signal distributor 12 remains in a stopped state,
Since the output signal k-n is not extracted, the reproduction level detection described above is not performed.

When the recording of the program signal is completed, the OR circuit 11 outputs a pulse again in response to the trigger pulse signal from the counter 9, and the signal distributor 12 and timer 1
A trigger signal a is supplied to 3.

Thereafter, in the same manner as described above, after the program signal is repeatedly recorded on the recording tape 8, test signals k'1 to n'3 as shown in FIG. 4 are recorded again, and the reproduction level is detected.

Here, if the playback level is outside the range of the reference level, the lamp drivers 4213 to 4224 are turned on, and the lamp L
13 to L24 are lit.

This makes it possible to discover malfunctions in the slave machine after recording the program signal, as well as defective duplicate tapes due to dirt that adhered to the recording head 26 while the tape was running.
Since signals are recorded on a track-by-track basis, it is possible to find out which part of the recording head 26 has dirt on it.

After recording test signals for playback level detection before and after the program signal on the recording tape 8 in this way, the signal S from the timer 13 is supplied to the flip-flop 43 when producing the next new recording tape. and resets the shift register 41.

In this embodiment, the level tolerance range is set regardless of the frequencies f1, f2, and f3, but a tolerance range is set for each test signal with a different frequency, and the playback level is tested for each frequency. It's okay.

In addition, in this example, three different frequencies such as frequencies f1, f2, and f3 were used, but test signals of the same frequency and different levels were recorded in advance, and the corresponding reference level was set using a potentiometer. The level linearity of the recording/reproducing process may be detected by a comparative test.

As described above, the copy level inspection method of the magnetic tape copying apparatus according to the present invention reproduces a first magnetic tape on which an information signal is recorded and copies the information signal onto another unrecorded second magnetic tape. a plurality of test signals different in at least one of frequencies and levels;
means for distributing test signals correspondingly to a plurality of tracks of a second magnetic tape; means for switching and recording a test signal with an information signal on a plurality of tracks of a second magnetic tape; Since it consists of means for performing full-width reproduction and detecting the reproduced signal level, and means for comparing the reproduced signal level from this detection means with a reference value, it is possible to detect defects in the copying device, such as a slave machine, before recording the information signal. It is possible to detect defects in the gain of the recording amplifier or defects in the frequency characteristics of each track, or to detect defects in the tape itself or wrong wrapping of the tape. It is possible to detect defective duplicate tapes due to dirt, etc. attached to the recording head during running, thereby preventing the production of defective duplicate tapes, and
In particular, since the signal is recorded for each track, it is possible to discover in which part of the recording head a defect has occurred, and since the playback system is a single system using a full-width playback head, it is possible to calibrate each track. The entire device can be easily configured without any variations in performance, and the failure rate can be reduced.Furthermore, since the playback track width is wide, errors caused by track misalignment during running can be reduced. , the means for switching and recording the information signal and the test signal consists of means for switching and recording the test signal on the second magnetic tape at a position before, after, or before and after the information signal; It has the advantage that the recording position of the test signal can be appropriately selected depending on the length of the test signal.

[Brief explanation of the drawing]

FIG. 1 is a block system diagram of one embodiment of the copy level inspection method of a magnetic tape copying apparatus according to the present invention, and FIG. 2A-
N and S are signal waveform diagrams for explaining the operation of the method of the present invention shown in FIG. 1, FIG. 3 is a specific circuit diagram of the signal distributor shown in FIG. 1, and FIG. 4 is a signal waveform diagram recorded by the method of the present invention. FIG. 5 is a signal waveform diagram for explaining the operation of the system of the present invention. 3... Master device, 8... Recording tape, 12... Signal distributor, 14... Sine wave oscillator, 24... Changeover switch, 26...
... Recording head, 27 ... Playback head, 3
1, 32... Comparator, 33, 34...
Potentiometer, 35, 36...Power supply voltage terminal, 41...Shift register, L1-L24.
·····lamp.

Claims (1)

[Scope of Claims] 1. A means for reproducing a first magnetic tape on which an information signal to be reproduced is recorded and duplicating and recording the information signal on another unrecorded second magnetic tape, and a frequency and level means for distributing a plurality of test signals, at least one of which is different, to the plurality of tracks of the second magnetic tape, respectively; and the information to be replicated on the plurality of tracks of the second magnetic tape. means for switching and recording the signal and the signal from the distribution means; means for reproducing the test signal in full width from the second magnetic tape and detecting the level of the reproduced signal; and the level of the reproduced signal from the detecting means. 1. A copy level inspection method for a magnetic tape copying apparatus, comprising means for comparing the signal with a reference value set corresponding to the test signal. 2. The means for switching and recording the information signal to be duplicated and the signal from the distribution means records the distributed plurality of test signals on the second magnetic tape before the information signal to be duplicated;
2. A copy level inspection system for a magnetic tape copying apparatus according to claim 1, further comprising means for switching recording to a rear or front or back position.