JPH0340258A - Servo device for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable consecutive recording without tracking distortion by controlling delay quantity so that phase difference can be fixed between the change point of an output signal from a frequency dividing means and the change point of an output signal from a delay means. CONSTITUTION:When the rotational phase of a capstan motor 5 is controlled by one capstan servo means 9, in a second capstan servo means 10, the delay quantity of the delay means is controlled by a first control means 103 so that the phase difference between the output signal from a delay means 101 and the output of a frequency divider 100 to divide the frequency of an output from a frequency generator 6. When a selecting means 11 is switched from the first capstan servo means 9 to the second capstan servo means 10, it is stopped by a second control means 102 to control the delay quantity with the first control means 103 and the delay quantity is fixed. Then, a capstan motor 5 is controlled by the second capstan servo means 10 with the output of the delay means as a reference so that the phase difference to the output of the frequency divider 100 can be fixed. Thus, consecutive recording can be executed while suppressing the tracking distortion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a single-rotation head type digital audio playback device, and particularly for recording a new signal following an already recorded signal. The present invention relates to a servo device for a magnetic recording/reproducing device suitable for continuous recording.

[Prior art] The conventional continuous shooting method for magnetic recording and reproducing devices is as follows.
An example thereof is described in Japanese Patent Application Laid-Open No. 62-287457. This is a splicing method for recording a synchronization signal on a magnetic tape and performing tracking control so that the reproduced synchronization signal is synchronized with a reference signal.
It is kept in the playback state and plays the synchronization signal on the magnetic tape,
The rotation speed of the campstan motor is controlled so that this playback synchronization signal is synchronized with the reference synchronization signal that is about to be recorded, and at the same time, a frequency generator is used to generate a signal with a frequency proportional to the rotation speed of the campstan motor. Generate a divided output of this signal.

The phase difference of the playback synchronization signal is measured, and then when recording a new signal, the phase is controlled using this frequency divider output and the reference synchronization signal, and the voltage corresponding to the measured phase difference is held. By adding the images, continuous shots can be taken.

On the other hand, digital audio tape recorder (DAT)
A rotary head type digital audio G recording/playback apparatus called JP-A-63-214946 has been devised, and its tracking control system is described in Japanese Patent Laid-Open No. 63-214946. This tracking method is called the ATF method, in which a pilot signal is recorded in each tracking, and tracking control is performed so that the amounts of pilot signals leaking from both adjacent tracks are equal during reproduction.

[The problem that the invention tries to solve! 1] However, such a tracking method has a left angle D
With AT, the synchronization signal is not recorded on tape, so
Control so that the playback synchronization signal is synchronized with the reference synchronization signal that will be recorded from now on, and measure the phase difference between the frequency division output of the frequency oscillator proportional to the rotational speed of the capstan motor and the playback synchronization signal. Therefore, there was a problem in that when continuous shooting was performed, tracking disturbances occurred at the joints.

It is an object of the present invention to solve such problems and to perform splicing without tracking disturbance even when tracking control is performed without recording a synchronization signal on a tape with a dedicated head on a dedicated track like ATF control etc. An object of the present invention is to provide a servo device for a magnetic i8 recording/reproducing device that enables the following.

[Means for Solving the Problems] In order to achieve the above object, the present invention comprises: a first capstan servo means for generating a first phase control signal from a tracking signal reproduced from a magnetic tape; a second capstan servo means for generating a signal with a frequency proportional to the rotational speed of the stun motor using a frequency generator, and generating a second phase control signal based on the signal of the frequency and the reference signal; In a servo device of a magnetic recording/reproducing device, the output signal of the frequency generator is separated. a frequency dividing means for rotating the reference signal; a delay means for delaying a change point of the reference signal; and when the selection means selects the first phase control signal by the first capstan servo means, the frequency dividing means a first control means for controlling the delay amount of the delay means such that a phase difference between a change point of the output signal of the output signal and a change point of the output signal of the delay means is constant; When the selection is switched from the first phase control signal by the first capstan servo means to the second phase control signal by the second capstan servo means, the delay amount of the delay means is changed by the selection means. The second capstan servo means is constituted by a second control means that fixes the amount of delay immediately before, and a phase comparison means that detects a phase difference between the output signal of the frequency dividing means and the output signal of the delay means. do.

[Operation] When the rotational phase of the capstan motor is controlled by the first capstan servo means, the second capstan servo means separates the output signal of the delay means and the output of the frequency generator. The delay amount of the delay means is controlled by the control means of [2] so that the phase difference with the output of the frequency divider is always constant. When the selection means switches to the first control means, the second control means stops the control of the delay amount by the first control means and fixes the delay amount, and the second capstan servo means changes the delay means output. As a reference, the capstan motor is controlled so that the phase difference with the frequency divider output is constant.

Thereby, from the first capstan servo means @2
Even when shifting to the second capstan servo means, the phase difference between the output of the frequency divider input to the second capstan servo means and the output of the delay device matches the state in which the phase error is zero.
The rotation speed of the capstan motor is not disturbed.
Therefore, it is possible to perform continuous shooting with less tracking disturbance.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a servo device of a magnetic recording/reproducing device according to the present invention, in which 1 indicates a rotating drum;
2A and 2B are heads, 3 is a magnetic tape, 4 is a capstan, 5 is a capstan motor, 6 is a frequency signal generator (FG) proportional to the rotation speed of the capstan motor, and 7 is a head switching signal SWH. 8 is a preamplifier; 9 is a frequency-voltage (FV) converter; 10 is an ATF control circuit; 11 is a switching switch; 12 is an adder; 13 is a counter; 14.
15 is a decoder (DEC), 16 is an edge detector, 17
is a counter, 18 is a decoder, 19 is a data grain circuit,
20 is a latch, 21 is an AND gate, 22 is a changeover switch, 23 is a counter, 24 and 25 are latches, and 26 is a P
WM converter, 27 is an input terminal for PWM conversion signal, 28 is an input terminal for reference signal 5REF, 29 is an input terminal for clock CK, 30.31 is a changeover switch, 100 is an FG ratio output frequency divider, 101 is a phase control 102 is a phase comparator, and 103 is a system control circuit.

The operation of this embodiment will be explained below.

First, in the playback state, the changeover switches 11, 22, 30.
31 is connected to the P side by the system control circuit 103. The P side of the switch 22 is at "H" level.

When the capstan motor 5 rotates, a signal with a frequency proportional to the rotational speed (FG multiplied signal is generated from the FG6,
The FV converter 9 converts the voltage into a voltage at a level corresponding to the frequency. At the same time, the ATF pattern signal recorded on the magnetic tape 3 is reproduced by the head 2A or 2B, and is supplied to the ATF control circuit 10, which is the second capstan servo means, via the preamplifier 8.
Alternatively, a voltage corresponding to the relative positional deviation between the scanning trajectory of 2B and the track on the magnetic tape 3 is output. The output voltage of the FV converter 9 and the output voltage of the ATF control circuit 10 are added by an adder 12, and the added output is supplied to the capstan motor 5 as a drive signal. Thereby, the rotational speed of the capstan 4 is controlled so that the relative position between the recording track on the magnetic tape 3 and the scanning trajectory of the heads 2A, 2B is kept constant.

Here, the number of FG pulses output from FG 6 per rotation of capstan motor 5 usually includes F when the capstan motor 5 is rotating at a normal rotation speed.
In many cases, the output frequency of G6 is selected to be twice the frequency of the reference signal 5REF input from the input terminal 28 during recording. In this embodiment as well, it is assumed that the number of pulses K is selected as described above.

A frequency divider 100 divides the output of the above-mentioned FG6 into .

That is, in the frequency divider 100, the DEC 14 detects that the counter 13 counts the output of the FG6, and when the count output becomes -1,
The counter 13 is cleared by outputting a clear pulse. As a result, the counter 13 repeatedly counts O--1 as one cycle. Furthermore, the decoder 15 outputs a pulse when the counter value of the counter 13 is N+1.

The output of this decoder 15 becomes a signal obtained by frequency-dividing the output of Fe2. Further, the counter 13 is preset to the value N when a preset signal is input from the phase control circuit 101 to its PR terminal.

The phase control circuit 101 delays the change point of the reference signal 5REF supplied from the input terminal 28 during recording and outputs the delayed signal.

That is, the falling edge of the input reference signal 5REF is detected by the edge detector 16, and the counter 17 is cleared by the detection output of the edge detector 16. When the counter 17 is cleared, it starts counting the clock GK from the input terminal 29, and the count value becomes M
When it becomes -1, it stops counting until it is cleared next time. The decoder 18 determines that the count value of the counter 17 is M
/2, a preset signal is output and the counter 13 is preset via the changeover switch 30. The latch 20 receives the reference signal 5RE via the AND gate 21.
F is supplied as a clock.

At the rising edge of this reference signal 5REF, the phase comparator 10
2 phase comparison data F is latched. The -number circuit 19 compares the output of the latch 20 and the count output of the counter 17, and outputs a match signal E when the two match. As a result, the falling edge of the reference signal 5REF is delayed according to the phase comparison data F, and this delayed falling edge is output as the coincidence signal E.

The phase comparator 102 measures the phase difference between the output of the changeover switch 31 in the phase control circuit 101 and the frequency-divided signal B of the FG signal A output from the frequency divider 100.

That is, the counter 23 is cleared by the output of the decoder 18 whose period is M, which is supplied via the changeover switch 31, and measures the phase difference in the first period after being cleared.
Otherwise, the phase difference measurement range will be exceeded. After being cleared by the output of the decoder 18, the counter value of the counter 23 at the time when the output signal B of the frequency divider 100 is supplied to the latch 24 as a clock is latched in the latch 24.

The output F of the latch 24 is the phase difference data between the output of the decoder 18 and the output signal B of the frequency divider 100, and the center value is M/2. The output data F of the latch 24 is further latched by the latch 25, and the PWM data F from the input terminal 27 is
The converted signal is converted into a PWM signal by PWM conversion 8126.

When the input signal 13 is preset to N by the output of the decoder 18, the frequency is divided! The output signal B of 100 rises within a time period of one wave of the FG pulse A from that point. FIG. 2 shows the output E of the coincidence circuit 19 and the frequency divider 11 when the output signal B of the frequency divider 100 appears at the center of its appearance range.
This shows the phase relationship of the output signal B of 00, so that this phase difference becomes M/2 by the count number of the counter 17.

-M times! Output E is output from 16L9.

That is, in FIG. 2, the time from the output of the decoder 15 to the rise of the output signal B of the frequency divider 11100 is latched by the latch 24, and the phase difference data (To) is latched by the latch 20. Therefore.

When the next falling edge of the reference signal 5REF is input, the output E of the coincidence circuit 19 is output when the count value of the counter 17 reaches To, and as a result, the minus number circuit 1
The phase difference between the rising edge of the output signal E of the frequency divider 9 and the output signal B of the frequency divider 100 is controlled to a value corresponding to M/2 by the count value of the counter 17.

Furthermore, FIGS. 3 and 4 show cases where the phase difference from the output of the decoder 18 to the rise of the output signal B of the frequency divider 100 is T and T x, respectively. In either case, The phase difference between the output E of the -number circuit 19 and the output signal B of the frequency divider 100 is controlled to be M/2.

Next, the operation of this embodiment when transitioning from reproduction to recording will be explained using FIG. 5. Note that FIGS. 5G and 5H show the output of the system control circuit 103 in FIG. 1.

In the reproduction state, the values w, x, y of data F when the output of the counter 23 is latched by the latch 24.

2, the position of the output E of the matching circuit 19 changes in the cycle of the next reference signal, 5REF. That is.

When the latch data F in the latch 24 of the output of the counter 23 is the value W, when the value of the counter F in the next cycle of the reference signal 5REF is W, the coincidence circuit 19 outputs the output E.

When transitioning from playback to recording, first, the changeover switches 22 and 30 are activated by the output G of the system control circuit 103.
．． 31 is switched to the R side. When the selector switch 30 is switched to the R side, the presetting of the counter 13 is stopped and only the frequency division operation of the FG signal A is performed. When the selector switch 22 is switched to the R side, the output of the AND gate 21 is "
Since the latch 20 is fixed at the "L" level, the data is no longer updated and the last data (2 in this case) before switching is held.Furthermore, when the changeover switch 31 is switched to the R side, the decoder The output E of the matching circuit 19 is supplied to the counter 23 as a clear signal instead of the output of the frequency divider 18.The phase difference between the output E of the number circuit 19 and the output signal B of the frequency divider 100 is approximately M/2. Therefore, in the first phase difference measurement after the changeover switches 22, 30.11 are switched to the R side, the latch output F at the latch 24 of the counter 23 is M/2 + α (α is error between the rotational speed of the capstan motor controlled by the second capstan servo means using the signal recorded on the magnetic tape and the rotational speed controlled by the first capstan servo means. .

Next, the changeover switch 11 is switched to the R side by the output H of the system control circuit 103, and the ATF control circuit 10
Instead, the capstan motor 5 is controlled by the phase comparator 102. After this.

The capstan motor 5 is controlled by the phase comparator 102 so that the phase difference between the output E of the minus number circuit 19 and the output B of the frequency divider 100 becomes M/2.

As described above, according to this embodiment, the rotational speed of the capstan motor 5 is not disturbed even when the reproduction state is changed to the recording state, and continuous shooting without tracking disturbance can be realized.

FIG. 6 is a block diagram showing another specific example of the phase control circuit 101 in FIG.
3 is a selection circuit, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In the figure, the falling edge of the reference signal 5REF detected by the edge detector 16 is detected by the M-stage shift register 32.
The 0 selection circuit 33 delayed by selects the tap of the shift register 32 corresponding to the output data of the latch 20, and outputs it to the output E corresponding to the selected tap.

Thereby, this phase control circuit 101 operates in the same way as the phase control circuit 101 shown in FIG.

1 is a diagram showing another embodiment of a servo device for a magnetic recording/reproducing apparatus according to the present invention, 34 is a matching circuit, and parts corresponding to those in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

This figure differs from the embodiment shown in FIG. 1 in that the preset input of the counter 13 and the switch 30 are omitted, and that where L is the period of the counter 17.23, L>M. . Further, FIG. 8 is a timing diagram showing the operation of FIG. 7, and d is the count value of the counter 17 when outputting the output of the decoder 18.

In the reproducing state, when the latch data F of the latch 24 of the counter 23 is the value W at a certain point in time, the count value of the counter 17 becomes (w-M/2+d) in the next cycle of the reference signal 5REF. When , the minus number circuit 30 outputs a coincidence output E.

The other operations are the same as those of the embodiment shown in FIG. 1 described using FIG. 5.

According to this embodiment, the number of rotations of the capstan motor 5 is not disturbed even when the state is changed from the reproduction state to the recording state, and therefore continuous shooting without tracking disturbance can be realized.

FIG. 9 is a block diagram showing still another embodiment of the servo device of the magnetic recording/reproducing apparatus according to the present invention, in which 35 is a matching circuit, and parts corresponding to those in FIG. Omit duplicate explanations. Also, Figure 10 shows the 9th
FIG. 3 is a timing diagram showing the operation of the figure.

First, the operation in the playback state of this embodiment will be explained.

In FIGS. 9 and 10, the counter 17 receives the reference signal 5.
Cleared on falling edge of REF.

Then, the rising edge of the output signal B of the 1 frequency divider 100 causes the latch 20 to latch the count 41ip of the counter 17. Thereafter, the -number circuit 35 outputs a coincidence output E when the count value of the counter 17 becomes P+M/2. The counter 23 is cleared by the rising edge of the output signal B of the frequency divider 100 and thereafter by the output E of the minus number circuit 35.

The count value of the counter 23 is latched into the latch 24. As a result, in the reproducing state, the output F of the latch 24 is always maintained at M/2.

Next, a case where the reproduction state changes to the recording state will be explained.

When the output G of the system control circuit 103 changes from the "H" level to the "L" level, the output of the latch 20 holds the last data (Q). At this time.

The phase difference between the output signal B of the frequency divider 100 and the output E of the matching circuit 35 is M/2+α (α is the AT value based on the reproduced signal.
(error between the rotational speed of the capstan motor 5 determined by the F control circuit IO and the rotational speed determined by the phase comparator 102). After that, by the output H of the system control circuit 103,
The changeover switch 11 closes to the R side, and the ATF control circuit 10
Therefore, the control of the capstan motor 5 is switched to the phase comparator 102, so that the phase difference is always M/2.
can be controlled to a constant value.

As described above, according to this embodiment, the rotational speed of the capstan motor 5 is not disturbed even when the reproduction state is changed to the recording state, and continuous shooting without tracking disturbance can be realized.

In this embodiment, the output E of the minus number circuit 35 is output after a delay of M/2 of the output signal B of the frequency divider 100, but when the latch 20 latches the value P, the next reference A similar effect can be obtained by outputting the signal at the timing when the count value of the counter 17 becomes (PM/2) in the period of the signal 5REF.

[Effects of the Invention] As explained above, according to the fifth aspect of the present invention, it is possible to suppress disturbances in tracking even when switching from the reproduction state to the recording state, and it is possible to always realize good continuous shooting.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of a servo device of a magnetic recording/reproducing apparatus according to the present invention, and FIGS.
FIG. 6 is a block diagram showing another specific example of the phase control circuit in FIG. 1, and FIG. 7 is a timing diagram showing the operation of the embodiment shown in FIG. 8 is a timing diagram showing the operation of the embodiment shown in FIG. 7, and FIG. 9 is a block diagram showing still another embodiment of the servo device of the magnetic recording/reproducing apparatus according to the present invention. 10 are timing charts showing the operation of the embodiment shown in FIG. 2A, 2B...head, 3...magnetic tape, 4...
・Capstan, 5... Capstan motor, 6...
・Frequency generator, 9...Frequency/voltage converter, 10・
・・AIF control circuit, 11 ・・changeover switch, 12
... Adder, 100 ... Frequency divider, 101 ... Phase control circuit, 102 ... Phase comparator. Ivy 1 Figure 2 Figure 5 %i'f;I4t No. 8 i+'

Claims (1)

[Claims] 1. A tracking signal recorded on a magnetic tape is reproduced, and a first
a first capstan servo means for generating a phase control signal; a frequency generator for generating a signal with a frequency proportional to the rotational speed of the capstan motor; and a second phase control means using the frequency signal and a reference signal. A second capstan servo means for generating a signal, and a selection means for selecting the first phase control signal during reproduction and selecting the second phase control signal during recording and supplying the selected signal to the capstan motor. , in a servo device for a magnetic recording and reproducing apparatus that controls the phase of the capstan motor, the second capstan servo means includes a frequency dividing means for dividing the output signal of the frequency generator, and a frequency dividing means for dividing the output signal of the frequency generator; delay means for delaying the change point of the output signal of the frequency dividing means and the change point of the output signal of the delay means when the selection means selects the first phase control signal by the first capstan servo means; A first control unit that controls the amount of delay of the delay means so that the phase difference between the change point and the output signal is constant.
and the delay means when the selection means switches the selection from the first phase control signal by the first capstan servo means to the second phase control signal by the second capstan servo means. a second control means for fixing the delay amount to the delay amount immediately before the switching of the selection means; and a phase comparison means for detecting a phase difference between the output signal of the frequency division means and the output signal of the delay means. A servo device for a magnetic recording/reproducing device, characterized in that the output signal of the phase comparison means is used as the second phase control signal. 2. In claim 1, the frequency dividing means is preset in synchronization with the reference signal when the selection means selects the first phase control signal by the first capstan servo means, and the selection means A servo device for a magnetic recording/reproducing device, characterized in that when selecting the second phase control signal by the second capstan servo means, the presetting is prohibited.