JPS6180543A - Phase adjusting device - Google Patents

Abstract

PURPOSE:To attain stable phase adjustment with good responsiveness by detecting the relative phase shift between a tape of a slave set and a tape of a master tape as a frame number and controlling a tape speed variable control means so as to run the tape to be coincident with each other when the phase adjusting frame number of the slave set is not coincident with the phase adjusting command frame. CONSTITUTION:An operating means 11 compares time code signals TC1, TC2 of the master set and the slave set, detects the relative position shift between tapes of both the sets is detected as a frame number and a phase adjusting command COM is fed to a phase adjusting quantity detecting means 12. The means 12 inputs a control output to a tape speed control command 13 at phase shift to output a speed control signal CON from the means 13 so as to increase stepwise the speed of an original tape via a slave set capstant drive system 3. A slave phase servo circuit 1 inverts the polarity of a phase error signal ERR because the period of a reproducing control pulse signal CTL is short, and when the 2nd polarity inversion waveform is counted, since the phase shift adjusting command frame number is coincident, the signal CON applies phase lock the tape of the slave set by using the signal CON at a normal speed so as to run the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a phase adjustment device, and is suitable for application to, for example, an editing device using a video tape recorder (VTR).

[Conventional technology]

In this type of editing device, the first VTR, which is the parent device,
On the other hand, when inserting a video signal and an audio signal from a second VTR, which is a slave unit, at a desired time code position, the video signal and audio signal are recorded on the tape of the slave unit at a predetermined time code position on the tape of the base unit. A so-called phase adjustment operation is required to match the time code at the beginning of the video signal.

In a conventional phasing device, after a so-called pre-roll operation is performed in which the tapes of the master unit and the slave unit are rewound in the reverse direction by a predetermined amount, a phasing operation is performed in which the tape is run in the forward direction in a playback mode. During this phase adjustment operation, the relative position difference between the editing start position and the current position of the parent unit's tape (i.e., master tape) and slave unit's tape (i.e., original tape) is detected, and if there is a difference, the Increase or decrease the tape running speed of the machine. This allows the editing start positions of each tape to reach the current position at the same time by performing phase adjustment control so that the relative positions from the current position to the editing start position are equal for each of the tapes of the master unit and slave unit.

[Problem that the invention seeks to solve]

In order to perform such adjustment operations, conventional phase adjustment devices repeatedly detect the deviation in the relative positions of the editing start points of the master unit and slave unit at predetermined time intervals, and adjust the tape of the slave unit based on the detection results. It is designed to determine whether to increase speed, decelerate, or leave the current state as it is. However, in this case, in order to perform variable speed control of the tape running speed of the slave unit, the current state of the tape in the master unit and the current state of the tape in the slave unit must be repeatedly detected each time and a determination result must be made. Therefore, it becomes more susceptible to disturbances and requires at least the time required for judgment and control. As a result, there are problems in that the phase adjustment operation becomes unstable due to disturbances, and the servo lock operation for controlling the tape of the slave device becomes slow.

The present invention has been made in consideration of the above points, and there is no need to repeatedly compare the tape position of the master unit and the tape position of the slave unit by simply generating a phase adjustment command. The present invention aims to provide a phase adjusting device that has high stability and can shorten the servo lock time of the tape of a slave device.

[Means for solving problems]

In order to solve this problem, in the present invention, the phase difference between the reference phase signal REF and the reproduction control pulse signal CTL obtained from the tape to be phased is detected in the phase servo circuit 1, and a phase signal representing the phase difference is detected. Obtain the error signal ERR and check whether the number of phase modulation command frames specified by the phase modulation command COM generated during phase modulation drive of the tape matches the number of phase modulation operation frames represented by the phase error signal ERR. The tape speed is detected by the phase adjustment ft detection means, and the tape is advanced or delayed by the tape speed variable control means responsive to the detection output of the phase adjustment amount detection means until the number of phase adjustment operation frames reaches the number of phase adjustment command frames. A speed control signal with the content of this is sent to the tape drive system 3, and when the number of phase adjustment operation frames matches the number of phase adjustment command frames as a result, the phase error signal ERR of the phase servo circuit 1 is sent to the speed control signal CO.
N, and the tape is sent to the tape drive system 3.

[Effect]

The phase adjustment command is made to express the relative positional deviation between the tape of the slave unit to be adjusted and the tape of the master unit as the number of frames, and the slave unit to perform the phase adjustment operation for this number of frames of the phase adjustment command. The current amount of deviation of the tape is constantly detected in the phase servo circuit 1 as the number of phase adjustment operation frames. The phase adjustment amount detection means 12 detects whether or not the number of phase adjustment operation frames is equal to the number of phase adjustment command frames, and if they do not match,
A speed control signal CON is sent from the tape variable control means 13 to control the tape speed variable control means 13 to run the tape in a direction that causes the tape to fail, and if the result is a loss, the phase servo circuit 1 phase error signal E
RR is sent as the speed control signal CON via the tape speed variable control means 13, and thereafter, the servo operation of the phase servo circuit 1 is used to draw the tape to the speed of the reference phase signal REF.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a slave phase servo circuit which obtains a phase error signal ERR at its output terminal and sends it to a phase adjustment control circuit 2. The phase adjustment control circuit 2 receives a time code signal TCI reproduced from the master tape of the parent unit VTR and a time code signal TC reproduced from the original tape of the slave unit VTR.
2, in the phase adjustment mode, the phase error signal ERR is processed and converted based on the deviation of the time code signal TCI and Te3, and the speed control signal CON is supplied to the capsun drive system 3.

The slave unit phase servo circuit 1 generates a phase error signal ERR representing the phase difference between the phase of the slave unit's original tape and the phase of the reference phase signal.
``Phase servo circuit 5'' described in the specification and drawings of No. 586
” configuration can be applied.

This slave unit phase servo circuit 1 receives a frequency pulse signal FG representing the rotational frequency of the capstan from the slave unit capstan drive system 3, and also reproduces control pulses recorded along the longitudinal direction on the original tape. The reproduction control pulse signal CTL (FIG. 2(B)) obtained by The slave unit phase servo circuit 1 receives the reproduction control pulse signal CT.
By having a counter that receives L as a reset signal, counting the frequency pulse signal FG by this counter, and converting the count output into an analog value,
Comparison sawtooth output WC representing the phase of the original tape (
Figure 2 (C)) is obtained. Here, the reproduction control pulse signal CT
L' is the same frequency as the frame frequency (30 (Hz))
On the other hand, the frequency pulse signal FG has a frequency several tens of times (for example, several hundred (Hz) to several (kHz)).

Therefore, the comparison sawtooth wave output WC obtained by counting the frequency pulse signal FG is a signal that has the same period as the reproduction control pulse signal CTL and that effectively changes continuously during the period (not intermittently). ). Since the pulse interval of the frequency pulse signal FC corresponds to the rotational speed of the capstan of the slave unit and therefore to the running speed of the original tape, the slope of the comparison sawtooth wave output WC represents the rotational speed of the capstan of the slave unit. There is. At the same time, the comparison sawtooth wave output WC is at the 0 level when the -0 reproduction control pulse signal CTL is given, and reaches the peak level when the next reproduction control pulse signal CTL arrives, so the comparison sawtooth Each instantaneous value of the wave output WC is the phase of the slave unit's capstan (therefore, the phase of one cycle of the control pulse recorded on the original tape)
This means that it is virtually continuous.

In addition to this, the slave phase servo circuit 1 receives a reference phase signal R.
It has a built-in integration circuit that receives 100 F (Fig. 2 (A)) as a reset signal, and its integrated output is used as the reference sawtooth wave output WR (
Figure 2 (C)) is obtained.

Here, the reference phase signal REF is 1/2 of the reference vertical synchronization signal.
Therefore, the reference sawtooth wave output WR has the same period as the reference phase signal REF, and is linear with a predetermined slope from the 0 level to the peak level during the period. go up and go. Therefore, each instantaneous value of this reference sawtooth wave output WR substantially represents the phase during one cycle of the reference phase signal REF.

The slave unit phase servo circuit 1 subtracts the comparative sawtooth wave output WC obtained in this way from the reference sawtooth wave output WR, and generates a phase error signal ERR (FIG. 2 (D)) based on the subtraction result.
get. Here, the phase error signal ERR indicates that the phase of the comparison sawtooth wave output WC is 1 with respect to the phase of the reference sawtooth wave output WR.
If the phase difference is 80° or more, the polarity is reversed when the phase difference reaches 180° (Fig. 2 (D)).

This means that when the comparative sawtooth wave output WC has a phase difference within 180° with respect to the reference sawtooth wave output WR, if the phase error signal ERR before polarity inversion is given to the child unit capstan drive system 3, This means that by controlling the speed of the capstan so as to eliminate the phase difference, the servo operation can be performed to phase-lock the comparison sawtooth output WC to the reference sawtooth output WR.

On the other hand, when the phase of the comparison sawtooth wave output WC with respect to the reference sawtooth wave output WR becomes a state where the phase difference is 180" or more, the comparison sawtooth wave output with respect to the reference sawtooth wave output WR in the current cycle The WC cannot be phase locked, and the servo is operated to lock the phase in the next cycle.

Therefore, the point at which the phase error signal ERR reverses its polarity represents the point at which the phase of the comparative sawtooth wave output WC leads or lags the phase of the reference sawtooth wave output WR by one period. become.

However, one cycle of the reference phase signal REF and the reproduction control pulse large signal CTL corresponds to one frame of the video signal recorded on the tape. Therefore, the phase error signal E
In the RR, if the number of occurrences of a waveform whose polarity is reversed from the peak value (this is called a polarity reversal waveform) is counted, the count value will be determined by the phase of the comparison sawtooth wave output WC (therefore the slave unit's This represents the number of times the edit point of the original tape overtakes the phase of the reference sawtooth wave output WR (therefore, one frame section of the master tape of the base unit).

In this way, the phase error signal ERR represents the number of phase adjustment operation frames that are phased by the adjustment response operation of the child device capstan drive system 3.

The phase adjustment control circuit 2 is composed of a microcomputer, and a
By processing the machine's time code signal TCI and the slave machine's time code signal TC2 in the calculation means 11, when the master tape and the original tape switch from the pre-roll state to the phase adjustment mode, the slave machine's original tape is Generates a phase adjustment command COM containing the number of phase adjustment frames indicating how many frames should be advanced or delayed with respect to the machine's master tape to match the editing position of the master tape and the editing position of the original tape. The signal is then applied to the phase adjustment amount detection means 12 and the tape speed variable control means 13.

The phase adjustment amount detection means 12 receives the phase error signal ERR supplied from the slave unit phase servo circuit 1, detects the direction of polarity inversion every time a polarity inversion waveform occurs, and counts the number of times the inversion waveform has occurred. Go. Then, while the count result is consistent with the contents of the phase adjustment command COM, the signal level of the speed control signal CON is set to the maximum level (this signal level is set to the capstan The signal level is set to a minimum level (the signal level is large enough to adjust the rotational speed of the capstan motor to the minimum speed) or the signal level is set to a minimum level (the signal level is large enough to adjust the rotational speed of the capstan motor to the minimum speed).

Further, when the phase adjustment 1 detection means 12 detects that the number of occurrences of the polarity inverted waveform of the phase error signal ERR matches the number of frames commanded by the phase adjustment command COM, the phase adjustment 1 detection means 12 performs tape speed variable control via the control output SEL. By controlling the means 13, the phase error signal ERR is sent out as it is as the speed control signal CON. As a result, the rotation speed of the capstan of the slave unit is adapted to lock the phase of the comparison sawtooth wave output WC to the phase of the reference sawtooth wave output WR by responding to the change in the signal level of the phase error signal ERR. Control.

When this phase lock state is achieved, the phase error signal ERR (signal level in FIG. 2(D) becomes O level).

In the above configuration, when the a machine and the slave machine shift from the pre-roll operation to the phase adjustment operation, the calculation means 11 compares the time code signals TCI and Te3 of the master machine and the slave machine, and calculates the relative positional relationship of the editing points. Based on this, it is determined how many frames the original tape of the slave unit should be advanced or delayed relative to the master tape of the master unit, and the phase adjustment amount detection means outputs a phase adjustment command COM containing the number of frames of the adjustment command. 12
Enter.

Here, at time t in FIG. 3, in the interval Wl before the phase adjustment command COM is generated, the phase adjustment amount detection means 1
2 is a tape speed variable control means 1 based on a control output SEL;
3 to send the phase error signal ERR as it is to the slave capstan drive system 3 as the speed control signal CON. Therefore, by the servo operation of the slave unit phase servo circuit 1, the phases of the slave unit's reference phase signal REF (FIG. 3(A)) and reproduction control pulse signal CTL (FIG. 3(B)) are in a phase-locked state.

Therefore, the slave unit phase servo circuit 1 operates in this phase lock section W.
1, a phase locked state is maintained in which the signal level of the phase error signal ERR becomes 0 level, as shown in FIG. 3(C). Then, the speed control signal CON controls the slave capstan drive system 3 to run the original tape at the normal speed SN (FIG. 3(D)).

Eventually, at time tll, the calculation means 11 outputs the phase adjustment command C.
The OM is sent to the phase adjustment amount detection means 12. Here, the calculation means 11 calculates the time code signals TC1 and Te of the master unit and slave unit.
3 and generates a phase adjustment command COM consisting of the number of phase adjustment command frames representing the difference and its direction based on the relative positional relationship of the editing points. In the case of the embodiment shown in FIG. 3, the editing point of the original tape of the slave unit is delayed by two frames with respect to the editing point of the master tape of the parent unit, and the calculation means 1 should advance by two frames accordingly. A phase adjustment command COM having the contents is sent to the phase adjustment amount detection means 12.

When the phase adjustment command COM is given, the phase adjustment amount detection means 12 controls the tape speed variable control means 13 using the control output SEL to set the maximum level or the minimum level (as shown in FIG. 3) according to the contents of the phase adjustment command COM. As a result, the slave unit capstan drive system 3 dramatically increases the speed of the slave unit's capstan and therefore the original tape to the maximum speed Ss ( Figure 3 (D)).

Thus, the slave unit enters the phase adjustment section W2 in Fig. 3, and the playback control pulse signal CT increases as the speed of the original tape increases.
The period of L becomes shorter (Fig. 3(B)).

At the same time, the slave unit phase servo circuit 1 changes the period of the comparison sawtooth wave output WC to the reference sawtooth wave output W by shortening the period of the reproduction control pulse signal CTL (Fig. 2 (B)).
Since the cycle is shorter than the period of R, as shown in FIG. 2(C) for the time interval delayed from time 1h, each time the comparative sawtooth wave output WC overtakes the reference sawtooth wave output WR by one frame. A polarity inversion waveform is generated that inverts the signal level of the phase error signal ERR from a negative level to a positive level (FIG. 2(D)).

In the interval W2 in which the slave unit performs the phase adjusting operation in this way, the first and second polarity inversion waveforms appear sequentially in the phase error signal ERR (Fig. 3(C)), and at this time, the original This means that the tape has advanced by two frames with respect to the master tape of the base unit.

Eventually, at time ttz, when the phase adjustment amount detection means 12 counts the second polarity inversion waveform of the phase error signal ERR, this count value (therefore, the number of phase adjustment operation frames) matches the number of phase adjustment command frames. It is determined that the phasing operation has been completed, and the tape speed variable control means 13 is controlled by the control output SEL, and the phase error signal ERR is sent directly to the speed control signal CON through the tape speed variable control means 13.
Switch to the state where it is sent as .

At this time, a closed loop for the slave unit phase servo circuit 1 is formed, so that the slave unit phase servo circuit 1 receives the phase error signal ERR.
Thus, at time t13 in FIG. 3, a pull-in operation is performed so that the phase error signal ERR becomes 0, and in response, the speed control signal CO
N decreases to pull the original tape of the slave device from the maximum speed S3 to the normal speed 8.4 (Figure 3 (
D)).

Therefore, in the interval W3 after time t13, the original tape of the slave unit runs in a phase-locked state with the master tape of the parent unit.

According to the configuration shown in FIG. 1, when entering a phasing operation, a phasing command CON is generated that expresses the relative positional shift between the master tape of the parent unit and the original tape of the slave unit by the number of frames, and In the phase servo circuit 1, the phasing operation of the original tape is detected in units of frame numbers based on the phase error signal ERR representing the phasing state of the original tape, and the detected frame number is the frame specified by the phasing command COM. The tape speed variable control means 13 forcibly controls the running speed of the original tape of the slave unit to the maximum speed or the minimum speed until the number matches the original tape of the slave unit. The phase can be adjusted to the master tape of the main unit.

In this way, the response operation of the original tape of the slave device can be detected with good responsiveness based on the phase error signal ERR of the slave device phase servo circuit 1, so that a responsive phasing operation can be realized.

(Effects of the Invention) As described above, according to the present invention, the number of phase adjustment frames of the original tape of the slave unit is detected based on the phase error signal ERR obtained from the slave unit phase servo circuit 1, and the number of phase adjustment frames of the original tape of the slave unit is detected.
The speed control signal CON for the capstan of the slave unit is switched to the maximum level or the minimum level until the number of frames specified by By obtaining the phase error signal ERR of the circuit 1 as the speed control signal CON, it is possible to obtain a phase adjustment device that performs phase adjustment operation with good responsiveness with a relatively simple configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the phase modifier according to the present invention, FIG. 2 is a signal wave diagram for explaining the configuration of the slave unit phase servo circuit 1, and FIG. 3 is the phase modifier of FIG. 1. FIG. 2 is a signal wave diagram showing signals of each part of FIG. 1...Slave unit phase servo circuit, 2...Phase adjustment control circuit, 3...Slave unit capstan drive system,
11...Calculating means, 12...Phase adjustment amount detection means, 13...Tape speed variable control means.

Claims (1)

[Scope of Claims] (a) A phase servo circuit that detects a phase difference between a reference phase signal and a reproduction control pulse signal obtained from a tape to be phased and generates a phase error signal representing the phase difference; (b) Whether or not the number of phasing command frames specified by the phasing command generated during phasing drive of the tape matches the number of phasing operation frames represented by the phase error signal. (c) advancing the tape until the number of phasing operation frames reaches the number of phasing command frames according to the detection output of the phasing amount detection means; A speed control signal is sent to the drive system of the tape, and as a result, when the number of phase adjustment operation frames matches the number of phase adjustment command frames, the phase error signal of the phase servo circuit is sent to the tape drive system. A phase adjustment device comprising: tape speed variable control means for sending a control signal to the tape drive system.