JPH0670272A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To provide a VTR which has no flow of a noise bar in a reproduced picture even at the time of a reproduction of an integer-fold speed for the normal reproduction speed and also in the other case of reproduction of variable speeds. CONSTITUTION:The control signal which is recorded on a tape 1 in a lengthwise direction of a tape 1 at the frame frequency (30Hz) is reproduced by a control head 2 and amplified up to a sufficient level by an amplifier 3. In a phase comparator 5 of the next stage the reproduced control signal outputted from the amplifier 3 compares the output of a pulse generator 15 in response to the data S outputted from a speed setting circuit 11 by a phase reference signal generator 14 with the phase reference signal produced by the output of a pulse generator 16. Thus the comparator 5 outputs a phase error signal. The phase error signal outputted from the comparator 5 and the speed error signal outputted from a speed control circuit 17 are added by an adder/amplifier 6 with a prescribed amplification factor. Thus a capstan error signal is obtained and a capstan motor 7 is driven.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium speed control system for variable speed reproduction of a magnetic recording / reproducing apparatus,
In particular, the present invention relates to a magnetic recording / reproducing apparatus capable of fixing bar noise even in variable speed reproduction other than the normal multiple speed reproduction.

[0002]

2. Description of the Related Art Magnetic recording / reproducing apparatus (hereinafter referred to as VTR)
In order to prevent noise bars from flowing in the search screen, it is necessary to keep the relative speed of the drum and tape constant. For this reason, speed control is performed so that the reproduction sync signal VD of the drum system becomes constant, and the reference signal of the phase control of the capstan system and the reference signal of the rotational phase control of the drum are made common to determine the relative speed of the drum and the tape. Keep it constant. A conventional control method is shown in a block diagram in FIG. In the figure, 1
Is a tape, 2 is a control head, 3 is an amplifier, 4 is a frequency divider, 5 is a phase comparator, 6 is a summing amplifier, 7 is a capstan motor, 8 is an amplifier, 9 is a frequency divider, and 10 is a speed control circuit. , 11 is a speed setting circuit for outputting tape running speed data, 12 is a pulse generator of a frame frequency (30 Hz), and 13 is a frequency generator (hereinafter abbreviated as FG).

The circuit configuration will be described. In the capstan speed control system, the FG signal obtained from the FG 13 is sufficiently amplified by the amplifier 8. The data Q output from the speed setting circuit 11 causes the frequency divider 9 to divide the frequency by 1 / Q (Q
Is set to a natural number) and the output FG signal of the amplifier 8 is set to 1 /
Divide by Q. The speed control circuit 10 compares the cycle of the frequency-divided FG signal output from the frequency divider 9 with the reference cycle T1 and outputs a speed error signal according to the cycle time difference. In the capstan phase control system, the control signal recorded at the frame frequency (30 Hz) in the longitudinal direction of the tape 1 is
It is reproduced by the control head 2 and amplified by the amplifier 3 to a sufficient level. The data P output from the speed setting circuit 11 causes the frequency divider 4 to divide the frequency by 1 / P (P
Is set to an integer), and the output control signal of the amplifier 3 is divided by 1 / P. The phase comparator 15 compares the phase of the frequency division control signal output from the frequency divider 4 with the frame reference signal output from the pulse generator 12 and outputs a phase error signal. The phase error signal and the speed error signal output from the speed control circuit 10 are added to the output of the speed system at a predetermined amplification factor in the adding amplifier 6 to become a capstan error signal. The capstan motor 7 is driven with a torque according to the capstan error signal.

Next, the operation will be described. The reference cycle of the speed control circuit 10 is a time T1 which is three times as long as the FG cycle at the normal reproduction speed.
Is set to. During normal speed reproduction, speed setting circuit 11
The frequency division ratio of the frequency divider 9 is set to ⅓ by the data P = 3 outputted by, and the frequency division ratio of the frequency divider 4 is set to 1 by the data Q = 1. As a result, in the speed control system, the output FG signal of the amplifier 8 is frequency-divided by the frequency divider 9 whose frequency division ratio is set to 1/3 by the data P = 3 output from the speed setting circuit 11. . Speed control circuit 1
In the case of 0, the divided FG signal is compared with the reference period T1 and the speed error signal corresponding to the period time difference is output. Since T1 is three times as long as the FG cycle at the normal reproduction speed, the normal reproduction speed is obtained. In the phase control system, the output control signal (30 Hz) of the amplifier 3 is output without being divided by the frequency divider 4 whose frequency division ratio is set to 1 by the data Q = 1 output from the speed setting circuit 11. To be done. The phase comparator 5 outputs the phase error signal so that the phase difference between the rising edge of the control signal (30 Hz) and the rising edge of the frame reference signal (30 Hz) becomes the reference phase difference T2. Therefore, the frequency division control signal is always kept in phase synchronization with the frame reference signal. During double speed playback,
The data P = 6 output from the speed setting circuit 11 sets the frequency division ratio of the frequency divider 9 to 1/6, and the data Q = 2 sets the frequency division ratio of the frequency divider 4 to 1/2. To be done. As a result, in the speed control system, the output FG signal of the amplifier 8 is frequency-divided by the frequency divider 9 whose frequency division ratio is set to 1/6 by the data P = 6 output from the speed setting circuit 11. . The speed control circuit 10 compares the frequency-divided FG signal with the reference cycle T1 and outputs a speed error signal corresponding to the cycle time difference. Since T1 is a time three times as long as the FG cycle at the normal reproduction speed, the reproduction speed is doubled. Also, in the phase control system, the tape speed at double speed reproduction is twice that at normal reproduction,
The playback control signal has twice the frequency (3
0 × 2 = 60 Hz). The output control signal (60 Hz) of the amplifier 3 is frequency-divided by the frequency divider 4 whose frequency division ratio is set to 1/2 by the data Q = 2 output from the speed setting circuit 11 and output. The phase comparator 5 is
The phase error signal is output so that the phase difference between the rising edge of the frequency division control signal (30 Hz) and the rising edge of the frame reference signal (30 Hz) becomes the reference phase difference T2. Therefore, the frequency division control signal is always kept in phase synchronization with the frame reference signal. That is, at integer multiple speed, the speed control circuit 10 determines that the divided FG signal and the reference period T
1 and the speed error signal corresponding to the cycle time difference is output. It can be seen that the frequency of the frequency division control signal output from the frequency divider 4 is always a constant frequency (for example, 30 Hz) regardless of the tape speed. Therefore, the frequency division control signal is always kept in phase synchronization with the frame reference signal. The frame reference signal is also used for phase control of the drum system, and the rotational phase of the drum is kept in phase synchronization with the frame reference signal. This means that even if the tape speed becomes an integral multiple, the phase of the noise bar always has a constant relationship with the rotational phase of the drum. Therefore, it is possible to perform easy-to-see integer multiple speed reproduction without the noise bar flowing.

At times other than integer multiple speed reproduction, for example, at 4/3 times speed reproduction, P = 4 is set from the speed setting circuit 11 and the tape speed 4/3 times speed is realized in the capstan speed control system as described above. Although it operates as possible, the capstan phase control system cannot be controlled by the above conventional technique. This will be described with reference to the timing chart of FIG. Here, 1001 is the phase difference T2. As described above, the data P output from the speed setting circuit 11
= 4, the tape speed becomes 4/3 times the speed during normal reproduction. The operation of the capstan phase control system at this time will be described. As shown in FIG. 10A, the frame reference signal is constant at the frame frequency. Since the tape running speed is 4/3 times, the control signal at 4/3 times speed (Fig. 10 (c)) is 4/3 times the frequency of the control signal at normal reproduction (Fig. 10 (b)). (For example, 30 × 4/3
= 40 Hz). However, the frequency divider 4 cannot easily realize the 3/4 frequency division. Here, it is assumed that the frequency division ratio of the frequency divider 4 is set to 1 by the data Q = 1 output from the speed setting circuit 11. The phase comparator 5 compares the phase difference between the rising edge of the control signal (40 Hz) and the rising edge of the frame reference signal (30 Hz) with the reference phase difference T2 and outputs a difference signal. At this time, FIG.
As described above, the phase difference between the rising edge of the control signal (40 Hz) and the rising edge of the frame reference signal (30 Hz) changes depending on the timing.

[0006]

Therefore, since the difference signal of the output from the phase comparator 5 does not become a correct phase error output, the phase control is not performed and the phase relationship between the running tape system and the rotating drum system is deviated. Therefore, there is a problem that a noise bar flows.

An object of the present invention is to provide a VTR in which a noise bar in a reproduction screen does not flow even during reproduction at an integral multiple speed of normal reproduction speed and other variable speed reproduction.

[0008]

In order to achieve the above object, the present invention provides a speed setting means for varying the traveling speed of a magnetic recording medium, a driving means provided with a capstan motor for driving the magnetic recording medium, A traveling speed control means for outputting a speed error signal so that the speed of the magnetic recording medium is always maintained at the set speed; a control signal detecting means for detecting a control signal recorded at a frame frequency on the magnetic tape; Phase control means for comparing the output signal of the signal detection means with a phase control reference signal in phase to output a phase error signal, and the speed error signal and the phase error signal are added at a predetermined amplification factor to drive control the drive means. Adder means for outputting a signal, first reference signal generating means for generating a frame frequency reference signal, and N times the frame frequency (N is a natural number)
Second reference signal generating means for generating the reference signal of 1), and the second reference signal is divided by 1 / S in accordance with the set speed data S (S is an integer) output from the speed setting means. It has a phase control reference signal generating means for generating the phase control reference signal synchronized with the first reference signal, and performs the phase control at the tape speed N / S double speed.

Further, in the magnetic recording / reproducing apparatus of the M segment recording system which divides one frame of the video signal into M segments (M is a natural number) by the rotary head and records on different recording tracks, the second reference signal Let the frequency be the rotation frequency of the drum.

[0010]

According to the present invention, the phase control reference signal of the capstan phase control system is generated by the phase reference signal generating means and the frame frequency reference signal is multiplied by N times the frame frequency according to the reproduction speed during variable speed reproduction. N is a natural number) or a segment frequency reference signal is generated according to the reproduction speed speed setting data S (S is an integer). As a result, the phase error can be detected even during the N / S double speed reproduction, the capstan phase control can be performed, and the phase of the noise bar always has a constant relationship with the rotational phase of the drum. Therefore, it is possible to provide a VTR capable of easy-to-see variable speed reproduction without the noise bar flowing.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. In FIG. 1, components having the same functions as those shown in FIG. 9 are designated by the same reference numerals. Where 1
Is a tape, 2 is a control head, 3 is an amplifier, 5 is a phase comparator, 6 is an addition amplifier, 7 is a capstan motor, 11 is a speed setting circuit for outputting the tape running speed data S, 17 is a speed control circuit, 14 Is a phase reference signal generator, 16 is a pulse generator for generating a reference signal of a frame frequency, 15 is synchronous with the output of the pulse generator 16 and has a frequency of N times the frame frequency (N is a natural number, for example 3). It is a pulse generator that generates a signal.

The circuit configuration will be described. In the capstan speed control system, the FG signal generated by the FG 13 is input to the speed control circuit 17. The speed control circuit 17 is FG
The cycle of the signal is compared with the reference cycle T3 set by the data S output from the speed setting circuit 11, and the speed error signal corresponding to the cycle time difference is output. In the capstan phase control system, the control signal recorded at the frame frequency (30 Hz) in the longitudinal direction of the tape 1 is
It is reproduced by the control head 2 and amplified by the amplifier 3 to a sufficient level. In the next phase comparator 5, the reproduction control signal output from the amplifier 3 is
The phase reference signal generator 14 compares the output S of the pulse generator 15 and the output of the pulse generator 16 with the generated phase reference signal corresponding to the data S output from the speed setting circuit 11. As a result, the phase comparator 5 outputs a phase error signal. The phase error signal output from the phase comparator 5 and the speed error signal output from the speed control circuit 10 are added to the summing amplifier 6
At, a predetermined amplification factor is added to form a capstan error signal. The capstan motor 7 is driven with a torque according to the capstan error signal.

Next, the operation will be described. In the normal reproduction capstan speed control system, the speed control circuit 17 compares the cycle of the FG signal generated by the FG 13 with the reference cycle T3 set by the data S = 3 output from the speed setting circuit 11 to cycle. A speed error signal corresponding to the time difference is output. To describe the capstan phase control system at this time, the value S = 3 is input to the phase reference signal generator 14 by the speed setting circuit 11. At this time, the phase reference signal generator 14 is synchronized with the output of the pulse generator 16 and the frequency of the pulse generator 16, that is, the frame frequency (30
(Hz) phase reference signal is output. The control signal recorded at the frame frequency (30 Hz) in the longitudinal direction of the tape 1 is reproduced by the control head 2,
After reaching a sufficient level by the amplifier 3, the phase is compared with the phase reference signal in the next phase comparator 5. The phase error output from the phase comparator 5 is added to the output of the speed system in the adding amplifier 6 in the next stage to drive the capstan motor 7. Therefore, the control signal is always kept in phase synchronization with the phase reference signal.

During 3/2 speed reproduction, the speed control circuit 17 determines the reference time T4 (T4 = S / N) according to the cycle of the FG signal generated by the FG 13 and the value S = 2 set by the speed setting circuit 11. XT3 = 2/3 × T3) and a speed error signal corresponding to the cycle time difference is output. At this time, the running speed of the tape becomes 3/2 times, and the reproduction becomes 3/2 times speed. At this time, the phase reference signal generator 14
By the data S = 2 output from the speed setting circuit 11,
The frame reference signal output from the pulse generator 16 (see FIG.
(A)) and the output of the pulse generator 15 (see FIG. 2).
A phase reference signal (FIG. 2C) having a frequency 1/2 times that of (b), that is, a frequency 3/2 of the frame frequency (30 × 3/2 = 45 Hz) is output. The control signal recorded at the frame frequency (30 Hz) in the longitudinal direction of the tape 1 is reproduced by the control head 2,
It is amplified to a sufficient level by the amplifier 3. At this time, the frequency of the reproduction control signal (FIG. 2 (d)) is N / S.
Since the reproduction is performed at double speed, the frequency becomes 3/2 times the frame frequency (30 × 3/2 = 45 Hz), which is the same frequency as the phase reference signal. The reproduction control signal is compared in phase with the phase reference signal in the phase comparator 5 in the next stage. The phase error output from the phase comparator 5 is added to the output of the speed system in the adding amplifier 6 in the next stage to drive the capstan motor 7. Therefore, the control signal is always kept in phase synchronization with the phase reference signal. When S = N, normal reproduction, when S> N, high speed reproduction, when S <N, slow reproduction, and when S <0, reverse reproduction. On the other hand, the frame reference signal output from the pulse generator 16 is also used for phase control of the drum system, and the rotational phase of the drum is kept in phase synchronization with the frame reference signal. This means that the phase of the noise bar always has a constant relationship with the rotational phase of the drum even if the tape speed increases N / S times. Therefore, it is possible to perform the variable speed reproduction which is easy to see without the noise bar flowing.

As described above, in the first embodiment of the present invention, the control signal is always synchronized with the rotational phase of the drum by generating the phase reference signal synchronized with the frame reference signal and controlling the capstan phase. There is an effect that it is possible to perform variable speed reproduction which is in a synchronous relationship and is easy to see without a noise bar flowing.

A second embodiment of the present invention will be described with reference to FIGS. In this embodiment, a case where the present invention is applied to a magnetic recording / reproducing apparatus for segment recording will be described. In FIG. 3, components having the same functions as those in FIGS. 9 and 1 are designated by the same reference numerals. Here, 1 is a tape, 2 is a control head, 3 is an amplifier, 5 is a phase comparator, 6 is an addition amplifier, 7 is a capstan motor, 11 is a speed setting circuit for outputting tape running speed data, and 13 is frequency power generation. Machine (hereinafter abbreviated as FG), 17 is a speed control circuit, 1
Reference numeral 4 is a phase reference signal generator, 16 is a pulse generator for generating a reference signal of a frame frequency, and 18 is a pulse generator 1.
6 is a pulse generator that generates a drum rotation frequency M times the frame frequency (M is a natural number in the number of segments) in synchronization with the output of 6. For this capstan control system,
There is no difference from what has been described with reference to FIG.
That is, as in the case of N = M in the first embodiment, the phase of the noise bar always has a constant relationship with the rotational phase of the drum even when the tape speed is M / S times.

The reproduced track and recorded information in this case will be described with reference to FIG. FIG. 4 shows a recording track pattern of a method of recording one frame of a video signal by dividing it into 6 segments, and a head scan pattern at 3/2 times speed. Reference numeral 1 is a tape, arrow 401 is a tape running direction, arrow 402 is a head scanning direction, 403 is a recording track, 404 is a head scanning locus, and 405 is segment information.

In segment recording, there is a possibility that a position where information necessary for video signal processing is recorded cannot be reproduced when variable speed reproduction is performed in order to record one field in a divided manner. For example, in the case of 3/2 speed, if the capstan phase control is performed by simply comparing the phases using a reference signal having a frequency three times the frame frequency, the segment 1
It is unknown whether the phase control is applied at the head of No. 4, the phase control is applied at the head of the segments 2, 5, or the phase control is applied at the head of the segments 3, 6. Therefore, in the case of a recording method in which the segment information 405 necessary for video signal processing is recorded only in the segment 1, this cannot be reproduced, and a stable variable-speed reproduced image cannot be obtained.

In the case of the present embodiment, by synchronizing with the frame reference signal and creating the phase reference signal from the segment reference signal of the drum rotation frequency, the phase control is always applied at the heads of the segments 1 and 4. This is an example.

As described above, in the second embodiment of the present invention, the capstan phase control is performed by dividing the reference signal of the drum rotation frequency in synchronization with the frame reference signal to generate the phase reference signal. As a result, the control signal is always in phase synchronization with the rotation phase of the drum, and variable speed playback is possible without noise bars flowing and segment information necessary for video signal processing in a specific recording segment can be played without fail. effective.

Next, a first specific example of the phase reference signal generator 14 will be described with reference to FIGS. 5 is a block diagram of a first specific example of the phase reference signal generator 14, FIG.
Is 3 in the first specific example of the phase reference signal generator 14.
It is a timing chart at / 4 speed. In the figure, 20 and 21 are frequency dividers, and 19 is a rising edge detector. However, the width of the output pulse of the rising edge detector 19 is sufficiently shorter than the reference signal period. The frequency divider 20 sets the second reference signal to 1 when the value S = 4 is set by the speed setting circuit 11 in correspondence with the tape speed 3/4 speed.
/ 4 division. The frequency divider 21 divides the first reference signal by 1/4 when the value S = 4 is set by the speed setting circuit 11. The rising edge detector 19 detects the rising of the output of the frequency divider 21 and sends a reset signal (FIG. 6 (e)) to the frequency divider 20. As a result, the frequency divider 20 newly starts 1/4 frequency division of the second reference signal from the time of resetting, and the phase reference signal (FIG. 6 (f)) synchronized with the first reference signal is newly generated. Output. There are four types of phase relationships between the input first reference signal and the output phase reference signal, but it is possible to make the phase relationship one type by resetting the frequency divider 20.

Next, a second specific example of the phase reference signal generator 14 will be described with reference to FIGS. 7 and 8. FIG. 7 is a block diagram of a second specific example of the phase reference signal generator 14, and FIG.
Is 3 in the second specific example of the phase reference signal generator 14.
It is a timing chart at / 4 speed. In the figure, components having the same functions as those in FIG. 5 are designated by the same reference numerals. Here, 22 is a preset D-flip-flop, and 23 is a detector that detects that the content of the speed setting circuit 11 has been updated and generates a detection pulse.
However, the pulse width output from the detector 23 is sufficiently shorter than the reference signal period. The frequency divider 20 divides the first reference signal by 1/4 when the value S = 4 is set by the speed setting circuit 11 in correspondence with the tape speed of 3/4. When the content of the speed setting circuit 11 is updated and the detector 23 generates a detection pulse (FIG. 8 (d)), the flip-flop 22 is set. Further, the flip-flop 22 is reset by the rising of the first reference signal, and a reset pulse having an output of a certain width (FIG. 8E) is obtained. As a result, the frequency divider 20 newly starts 1/4 frequency division of the second reference signal from the time when the reset pulse falls and the reset is applied, and the phase reference signal synchronized with the first reference signal (see FIG. f)) is output. There are four types of phase relationships between the input first reference signal and the output phase reference signal, but it is possible to make the phase relationship one type by resetting the frequency divider 20. In this method, a target phase error signal of one type of phase relationship is output and control is performed earlier than in the example described with reference to FIG.

[0023]

According to the present invention, the frame frequency output from the pulse generator and the frame frequency reference signal generator, which outputs the frequency N times (N is a natural number) the frame frequency in synchronization with the reference signal of the frame frequency. By creating the phase control reference signal from the reference signal in correspondence with the tape speed information S (S is an integer), even if the tape speed becomes N / S times, the phase control reference signal with the frequency of N / S times can be obtained. N / S
Capstan phase control can be performed by comparing the phase with a reproduction control signal having a double frequency. This phase reference signal is synchronized with the second reference signal used for the phase reference of the rotation of the drum. As a result, the phase of the noise bar can always be kept in a constant relationship with the rotational phase of the drum, and there is an effect that a variable-speed playback screen that is easy to see can be obtained without the noise bar flowing. By setting N to be equal to the number of segment divisions M at the time of segment recording, the tape speed is N
Since the segment information recorded at a specific position of the recording track can be stably reproduced at the / S double speed, there is an effect that a stable N / S double speed variable speed reproduced image can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a magnetic recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a timing chart showing the operation of the first embodiment.

FIG. 3 is a block diagram showing a configuration of a magnetic recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing a head scan pattern on a tape during segment recording in the second embodiment.

FIG. 5 is a phase reference signal generator 14 shown in FIGS.
Block diagram showing a first concrete example of

6 is a timing chart showing the operation of the phase reference signal generator in FIG.

FIG. 7 is a phase reference signal generator 14 shown in FIGS. 1 and 3;
Block diagram showing a second specific example of

8 is a timing chart showing the operation of the phase reference signal generator in FIG.

FIG. 9 is a block diagram showing the configuration of a conventional magnetic recording / reproducing apparatus.

FIG. 10 is a timing chart showing the operation of the conventional example.

[Explanation of symbols]

 1 tape 2 control head 3,8 amplifier 4,9,19,20 frequency divider 5 phase comparator 6 summing amplifier 7 capstan motor 10,17 speed control circuit 11 speed setting circuit 12 frame frequency pulse generator 13 frequency generator 14 phase reference signal generator 15, 16 and 18 pulse generator 21 edge detector 22 flip-flop 23 detector 403 recording track 404 head scanning locus

Claims (2)

[Claims] 1. A speed setting means for varying a traveling speed of a magnetic recording medium, a driving means for driving the magnetic recording medium, and a speed error signal for always maintaining the speed of the magnetic recording medium at a set speed. Speed control means, control signal detection means for detecting a control signal recorded at a frame frequency on the magnetic tape, and phase comparison of the output signal of the control signal detection means with a phase control reference signal to output a phase error signal. Phase control means, addition means for adding the speed error signal and the phase error signal with a predetermined amplification factor and outputting a drive control signal to the drive means, and a first reference signal generation for generating a frame frequency reference signal. Second means for generating a reference signal in synchronization with the frame frequency reference signal and N times (N is a natural number) the frame frequency
Of the reference signal generating means, the second reference signal is 1 / S in accordance with the set speed data S (S is an integer) output from the speed setting means, and the first reference signal is obtained. A magnetic recording / reproducing apparatus comprising phase control reference signal generating means for generating the synchronized phase control reference signal, and performing phase control at a tape speed of N / S. 2. A second reference signal in an M segment recording type magnetic recording / reproducing apparatus for dividing one frame of a video signal into M segments (M is a natural number) by a rotary head and recording on different recording tracks. The magnetic recording / reproducing apparatus according to claim 1, wherein the frequency is a rotation frequency of the drum.