JPH11232738A - Magnetic recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording/reproducing device accelerating drawing operation at a special reproducing time and performing stable APC (automatic phase control) control. SOLUTION: A means where one among plural FGs(frequency generator sensors) outputted at every one revolution of a drum not related to a delay amount of a PG(phase detection sensor) mono-multivibrator is selected as a signal of a side to be phase compared, and switching that signal to an HSW (switching pulse) being the signal to be phase compared in recording, unmagnified speed reproducing mode is added to the device. Further, since when regular reproducing (unmagnified speed) is shifted to the special reproducing, and when the special reproducing is shifted to the regular reproducing (unmagnified speed), the signal to be phase compared is switched respectively to the HSW signal and the FG signal, by selecting the FG signal with the phase nearest to the HSW signal with an FG selection part 16 for shortening a drawing time, the fast drawing operation and stable drum APC control is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rotation control of a rotary head drum of a DV format helical scan VTR.

[0002]

2. Description of the Related Art In recent years, with the remarkable progress in digital technology, DV format VTRs for digital recording and reproduction of system data and the like relating to video, audio, and tape on a magnetic tape have become widespread for home video. Hereinafter, a conventional technique will be described.

FIG. 4 is a block diagram showing a configuration of a rotary head drum and a control circuit in a conventional magnetic recording / reproducing apparatus. 1 is a rotary head drum having a magnetic head and capable of recording and reproducing various signals on a magnetic tape 2 by rotating, 2 is a magnetic tape on which a predetermined amount of signal is wound around the rotary head drum 1 and 3 is a rotary head drum 1 A frequency generator sensor (hereinafter, referred to as an FG sensor), which is a rotation speed detecting means for detecting a rotation frequency of the FG sensor and outputting an FG signal, 4 is an FG, a speed signal amplifying means for amplifying the FG signal from the FG sensor 3. The amplifier 5 is a frequency discriminator for extracting a modulation signal from the FG signal from the FG amplifier 4, and the reference numeral 6 is a notch filter that does not pass only a signal of a predetermined frequency from the modulation signal from the frequency discriminator 5. And a rotation frequency that is an integral multiple of the normal rotation frequency is not passed, and a rotation error is output as an error voltage. The frequency discriminator 5 and the notch filter 6 constitute speed control means.

[0004] Reference numeral 7 denotes a phase detection sensor (hereinafter referred to as PG) which is a phase detection means for detecting a rotation phase of the rotary head drum 1 and outputting a PG signal.
A PG amplifier which is a phase signal amplifying means for amplifying the G signal,
9 is a PG monomulti which adjusts the PG delay time of the PG signal, 21 is an internal reference signal generator for generating a first reference signal in the apparatus, and 22 is a second reference signal input from outside such as a video signal. A reference signal input unit 23 for switching between a signal from the internal reference signal generation unit 21 and a signal from the reference signal input unit 23 to output the APC reference signal 11; At the time, it is connected to the reference signal input unit 23 side, and at the time of special reproduction, it is connected to the internal reference signal generation unit 21 side. A phase comparator 10 for comparing the phase of the PG signal from the PG monomulti 9 with the APC reference signal 11 and outputting the error as an error voltage;
24 is a mixing circuit which is a mixing means for mixing the error voltage from the notch filter 6 and the error voltage from the phase comparator 10, and 12 controls the driving of the rotary head drum based on the error voltage mixed by the mixing circuit 24. A driving circuit 13 as a driving means is a PG output from the PG monomulti 9.
A head switching pulse (hereinafter, referred to as an HSW signal) for switching a plurality of heads provided on the rotary head drum 1 is a signal. Minute. Seconds. A subcode gate creator for generating a subcode gate signal including a frame signal, etc., 20 is an HSW from the PG monomulti 9
This is a video circuit to which a signal and an SCG signal from the subcode gate creator 14 are input.

The operation of the conventional magnetic recording / reproducing apparatus configured as described above will be described below.

A pair of magnetic heads are attached to the rotary head drum 1 and record and reproduce video and audio signals on the magnetic tape 2 transported in the direction of arrow B while rotating in the direction of arrow A. The FG sensor 3 detects the rotation frequency of the rotary head drum 1 and amplifies it with an FG amplifier 4 and then sends it to a frequency discriminator 5 for automatic frequency control (hereinafter A).
FC control) to perform speed control. The output signal of the frequency discriminator 5 is input to the notch filter 6. The notch filter 6 does not pass only a specific frequency, and removes unevenness of the FG signal for one rotation of the rotary head drum.

FIG. 5 shows the output signal characteristics of the notch filter 6 in this configuration. The rotation frequency of the rotary head drum of the DV format is about 150 [Hz], and as shown in FIG. 5, it has a characteristic of not passing a frequency of 150 [Hz], which is an integral multiple thereof. As described later, the characteristic is such that low-frequency components including the DC component are not passed. Therefore, when the rotation frequency is not 150 [Hz] or a frequency that is an integral multiple of 150 [Hz], the error is output as an error voltage.

On the other hand, the rotary head drum 1 is detected by the PG sensor 7.
After the rotation phase is detected and amplified by the PG amplifier 8, the PG monomulti 9 adjusts the PG delay time in order to correct the mounting error between the PG signal and the video head. PG Mono Multi 9
Is sent to the video circuit 20 as the HSW signal 13 and is also input to the phase comparator 10. In the phase comparator 10, the PG signal from the PG monomulti 9 and the AP
The phase comparison with the C phase reference signal 11 is performed, and the error is output as an error voltage.

The APC reference signal 11 includes a reference signal from an internal reference signal generator 21 and an external reference signal input unit 22.
And a reference signal input through the switch 23. The reference signal from the reference signal input unit 22 is input to the phase comparator 10 during recording and reproduction, and the internal reference signal is input during special reproduction. The reference signal from the signal generator 21 is input to the phase comparator 10.

The error voltage of the AFC system from the notch filter 6 and the error voltage of the APC system from the phase comparator 10 are mixed by the mixing circuit 24 and input to the drive circuit 12. The drive circuit 12 controls the rotation of the rotary head drum 1 based on the error voltage so as to correct the error of the rotation frequency and the rotation phase.

On the other hand, the H output from the PG monomulti 9
The SW signal 13 is input to the video circuit 20 and also to the subcode gate generator 14. In the subcode gate creator 14, based on the HSW signal 13, an SC indicating the subcode recording position on the magnetic tape 2 is set.
A G signal is created and input to the video circuit 20. In the video circuit 20, the rotary head drum 1 is
The sub-code is recorded at a predetermined position on the magnetic tape 2 by the SCG signal while controlling the switching of the plurality of magnetic heads provided on the magnetic tape 2.

Next, the relationship between the signals in the present apparatus will be described with reference to FIGS. FIG. 6 is a schematic diagram showing a track pattern of the DV format, and FIG. 7 is a timing chart of each signal in the present apparatus.
In FIG. 6, reference numeral 51 denotes a search signal or a time signal (hour, minute,
Seconds) and subcode recording area where frame signals are recorded, 5
Reference numeral 2 denotes a video signal recording area in which a video signal is recorded, and 53, an audio signal recording area in which an audio signal is recorded. FIG.
Where (a) is an FG signal, (b) is a PG signal,
(C) is an output signal of the PG mono multi 9, and (d) is an HSW.
The signal, (e) is a track pattern recorded on the magnetic tape 2 as shown in FIG. 6, (f) is an SCG signal, and (g) is an APC reference signal 11. Here, the FG signal (a),
PG signal (b), PG mono multi output signal (c), H
The SW signal (d), the track pattern (e), and the SCG signal (f) are synchronized with each other, and the phase of the HSW signal (d) is synchronized with the APC reference signal (g).

[0013] PG signal (FIG. 7 (b)) is converted into a signal shown in FIG. 7 (c) by PG mono-multi 9, T _M time-delayed HSW signal from the PG signal on the basis of the signal (Fig. 7
(D)) is made. In the DV format, a search signal and a time signal (hour, minute, and so on) are supported in order to support a high-speed search function for searching for a desired recording position on the magnetic tape 2 at a high speed.
Second), a subcode recording area 51 in which a frame signal is recorded.
Is set. In high-speed search, magnetic tape 2
When reading the subcode signal recorded in the subcode recording area 51 of the subcode gate area 51, the subcode gate creator 1
In step 4, an SCG signal (FIG. 7 (f)) synchronized with the HSW signal (FIG. 7 (d)) is generated, and the subcode signal and the video signal are reliably separated and read. Where SC
The G signal (FIG. 7F) is created by setting a predetermined delay time T _D from the edge of the HSW signal (FIG. 7D) and the pulse width T _S of the SCG signal.

FIG. 8 is a schematic diagram showing a track pattern of a helical scan type VTR. In FIG. 8, 71
Represents a first head trajectory which is a head trajectory at the time of normal reproduction;
Reference numeral 2 denotes a second head trajectory which is a head trajectory at the time of 5 × fast forward reproduction, and reference numeral 73 denotes a third head trajectory which is a head trajectory at the time of still image reproduction.

As shown by the second and third head trajectories 72 and 73, the relative speed between the magnetic tape and the magnetic head changes during the special reproduction in which the magnetic tape is sent at a speed different from that at the time of recording. This is due to the helical scan recording. The adjacent tracks are recorded with a step α as shown in the figure. For example, as shown by the second head locus 72 in the figure, at the time of fast forward reproduction at 5 × speed, the length of the magnetic head 1 scanning period is reduced by four steps α. Generally the length L _n of the head 1 scan period is n-times speed,

[0016]

(Equation 1)

In order to correct this, the rotational speed of the rotary head drum 1 is changed and corrected. Therefore, the rotational speed correction rate ε (%) is

[0018]

(Equation 2)

## EQU1 ## At this time, the cycle of the HSW signal (T
_HSW ), the period of the FG signal, and the period of the PG signal also have the correction factor ε.
It changes with.

The rotation speed of the rotary head drum 1 changes according to the correction rate ε of the rotation speed of the rotary head drum 1 corresponding to the tape speed, and the cycle ( _THSW ) of the HSW signal also changes. Similarly, the delay time T _M due to the PG monomulti 9, the delay time T _D from the edge of the HSW signal in the SCG signal, and the subcode pulse width T _S are similarly corrected.
Must be controlled accordingly.

For example, the tape speed is changed from 1 × speed, which is the same speed as at the time of recording, to 60 ° in the fast forward playback mode.
When changing to double speed, the rotation speed of the rotary head drum 1 is 1
The speed becomes 111% of the speed at the time of double speed. However, REW
When the mode changes to −60 × speed, the rotation speed of the rotary head drum 1 becomes 89% of the speed at 1 × speed, and it takes some time to reach this speed. In the transition period in which the rotation speed of the rotary head drum 1 is changing, the period T _{HSW of the} HSW signal, the period of the FG signal, and the period of the PG signal change in proportion to the rotation speed, but T _M and T _D. , T _S is the time when the rotation of the rotary head drum 1 starts to accelerate or decelerate during the mode change, that is, before the rotation speed has not yet reached the target rotation speed.
When the magnetic head scans the sub-code recording area 51, the adjacent video signal recording area 52 may be erroneously scanned, since the correction rate ε is switched to the correction rate ε corresponding to the target rotation speed.
The SCG signal may interfere with the video signal recording area 52.

At the time of special reproduction in which reproduction is performed at a tape speed different from that at the time of recording, the rotation speed of a drum motor (not shown) of the rotary head drum 1 is changed in order to correct the relative speed change between the magnetic head and the magnetic tape. is, the rotation speed of the change rate of the drum motor during the special reproduction with respect to the rotational speed of the recording time of the drum motor (relative speed correction factor), by measuring the period of the HSW signal (T _HSW) by HSW synchronous measurement unit 15 It calculates and changes the delay amount ( _TM ) of the PG monomulti 9 in proportion to the calculated value. Also, similarly to the delay amount of the PG monomulti 9, the HSW in the SCG signal is used.
And to vary the relative position T _D and the pulse width T _S from the signal.

In addition to the above-mentioned special reproduction, the same applies to the transition from normal reproduction (1 × speed) to special reproduction, from special reproduction to normal reproduction (1 × speed), and from special reproduction to special reproduction at a different tape speed. The problem was solved by letting it work.

In FIG. 4, reference numeral 15 denotes H for measuring _THSW.
In SW synchronous measurement unit, the correction factor epsilon (%) and 1 at double speed of T _HSW (reference) in the measurement of the special playback of T _HSW was calculated by the following equation (3), T _M, T _D, the T _S I try to change.

[0025]

(Equation 3)

The recording and 1 × speed reproduction are performed in the phase comparator 10 at 150 [Hz] (NTSC is 1/14) input from the video processing block via the reference signal input unit 22.
9.85 [sec], PAL is 1/150 [sec])
Reference signal (external reference) and PG mono multi 9
In contrast to the comparison with the HSW signal from the internal reference signal generator, since the rotation speed of the rotary head drum 1 is different from that during recording and 1 × speed reproduction for the relative speed correction during special reproduction, This is a phase comparison between the reference signal (internal reference) from H.21 and the HSW signal.

Regarding the AFC control and the APC control at the time of the special reproduction, the notch filter 6 arranged in the AFC control system shown in FIG. 4 has a characteristic that does not pass low frequency components including the DC component. In order to compensate for this low-frequency error component, APC control during special reproduction is necessary when the notch filter 6 in the AFC control exists.

[0028]

However, in the above-mentioned conventional configuration, the following problems occur due to the APC control using the reference signal (internal reference) and the HSW signal at the time of special reproduction.

The operation at the time of rewind reproduction includes (1) the rotational head drum 1 is decelerated by the relative speed correction, (2)
(3) The T _M value is increased in proportion to the cycle of the HSW signal, (4) the phase of the HSW signal is shifted with respect to the internal reference signal from the internal reference signal generation unit 21, (5) Perform phase control; (6) Accelerate the rotation of the rotary head drum 1; (7) Shorten the cycle of the HSW signal; (8) Decrease the T _M value in proportion to the cycle of the HSW signal (9) the phase of the HSW signal is shifted with respect to the internal reference signal, (10) the phase control is performed, (11) the rotation of the rotary head drum 1 is decelerated, and (12) the cycle of the HSW signal is increased ((( (Return to 2)). However, in such an operation, there is a problem that the rotation of the T _M and the rotation of the rotary head drum 1 is not stable or it takes time to stabilize.

Also, in the fast forward reproduction, the operation is completely opposite to that in the rewind reproduction, (1) the rotation of the rotary head drum 1 is accelerated by the relative speed correction, (2) the cycle of the HSW signal is shortened, and (3) ) Decrease the T _M value in proportion to the cycle of the HSW signal, (4) shift the phase of the HSW signal with respect to the internal reference signal, (5) perform phase control, (6) decelerate the rotary head drum 1 (7) The period of the HSW signal is increased, (8) the T _M value is increased in proportion to the period of the HSW signal, (9) the phase of the HSW signal is shifted with respect to the internal reference signal, and (10) the phase. Control is performed, (11) the rotation of the rotary head drum 1 is accelerated, and (12) the cycle of the HSW signal is shortened (return to (2)). T _M and rotary head drum 1 Or rotation is not stable, there is a problem that it takes time to stabilize.

The present invention has been made to solve the above-mentioned problem.
It is an object of the present invention to provide a magnetic recording / reproducing device capable of performing control.

[0032]

In order to achieve this object, a magnetic recording / reproducing apparatus according to the present invention comprises: a rotating head drum having a magnetic head for recording and reproducing signals on a recording medium; Rotation speed detection means for detecting the rotation speed, speed signal amplification means for amplifying the rotation speed signal detected by the rotation speed detection means, speed control means for detecting unevenness in the rotation speed signal and outputting a first error signal; Selecting means for selecting a predetermined speed signal from the speed signals from the speed signal amplifying means, phase detecting means for detecting the rotation phase of the rotary head drum, and phase signal amplification for amplifying the rotational phase signal from the phase detecting means Means, a PG monomulti for adjusting the delay time of the phase signal output from the phase signal amplifying means, and either an output signal from the selection means or an output signal from the PG monomulti. A second switching means for selecting,
First switching means for switching between a first reference signal set inside the apparatus and a second reference signal input from the outside, and outputting the signal selected by the second switching means; A phase comparison unit that compares the reference signal from the switching unit and outputs the comparison result as a second error signal; a first error signal from the speed control unit; and a second error signal from the phase comparison unit. And a driving means for controlling the rotation of the rotary head drum to be corrected based on the error signal mixed by the mixing means.

With such a configuration, the pull-in operation is performed quickly during special reproduction, and stable APC control can be performed.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claims 1 and 2 of the present invention detects a rotating head drum having a magnetic head for recording and reproducing signals on a recording medium, and a rotating speed of the rotating head drum. Rotating speed detecting means, a speed signal amplifying means for amplifying the rotating speed signal detected by the rotating speed detecting means, a speed controlling means for detecting unevenness of the rotating speed signal and outputting a first error signal, and a speed signal amplifying means. Selecting means for selecting a predetermined speed signal from the speed signals from the means, phase detecting means for detecting the rotational phase of the rotary head drum, phase signal amplifying means for amplifying the rotational phase signal from the phase detecting means, PG monomulti for adjusting the delay time of the phase signal output from the signal amplifying unit, and a second switch for selecting either the output signal from the selecting unit or the output signal from the PG monomulti. Switching means for switching between a first reference signal set inside the apparatus and a second reference signal input from the outside, and a signal selected by the second switching means. And a reference signal from the first switching means, and outputs a result of the comparison as a second error signal; and a first error signal from the speed control means and a second error signal from the phase comparing section. Mixing means for mixing the error signal of the rotary head drum and a driving means for controlling the rotation of the rotary head drum based on the error signal mixed by the mixing means. By selecting a signal closest to the rising timing of the HSW signal as a signal to be compared with the phase of the APC control and performing the phase comparison, stable APC control with a fast pull-in operation is realized. It is possible.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram showing a configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.
Is a rotary head drum having a magnetic head and capable of rotating and recording and reproducing various signals on a magnetic tape 2, a magnetic tape 2 wound around the rotary head drum 1 by a predetermined amount to record various signals, and 3 a rotary head drum 1 Detecting rotation frequency and F
An FG sensor that is a rotation speed detecting unit that outputs a G signal,
Reference numeral 4 denotes an FG amplifier which is a speed signal amplifying means for amplifying the FG signal from the FG sensor 3;
A frequency discriminator 6 for extracting a modulation signal from a signal is a notch filter that does not pass only a signal of a predetermined frequency from the modulation signal from the frequency discriminator 5. In this configuration, the normal rotation frequency of the rotary head drum 1 and an integral multiple of the normal rotation frequency are used. The rotation frequency is not passed, and the signal passing through this filter is a rotation error, which is output to the mixing circuit 24 as an error voltage. The frequency discriminator 5 and the notch filter 6
These constitute the speed control means.

7 is a PG sensor which is a phase detecting means for detecting the rotation phase of the rotary head drum 1 and outputs a PG signal; 8 is a PG amplifier which is a phase signal amplifying means for amplifying the PG signal from the PG sensor 7; 9 is a PG mono multi for adjusting the PG delay time of the PG signal, and 16 is an F
An FG selection unit that is a selection unit that selects an FG signal having the phase closest to the HSW signal among the FG signals from the G amplifier 4;
Reference numeral 17 denotes a second switch which is a second switching means for switching a signal input to the phase comparator 10 between recording and 1 × speed reproduction and special reproduction, and is connected to the terminal b during recording and 1 × speed reproduction. During special playback, connect to terminal a. 21
Is an internal reference signal generating section for generating a first reference signal inside the apparatus, 22 is a reference signal input section for inputting a second reference signal from the outside such as a video signal, and 23 is a signal from the internal reference signal generating section 21. A first switch, which is a first switching means for switching between a signal and a signal from the reference signal input unit 23 and outputting the APC reference signal 11, is connected to the reference signal input unit 23 during recording and reproduction, and During reproduction, it is connected to the internal reference signal generator 21 side.

Reference numeral 10 denotes a signal from the second switch 17 and A
A phase comparator for comparing the phase with the PC reference signal 11 and outputting the error as an error voltage;
A mixing circuit for mixing the error voltage from the phase comparator 10 and the error voltage from the phase comparator 10;
4 is a drive circuit which is a drive means for controlling the drive of the rotary head drum based on the error voltage mixed in 4. A plurality of heads provided on the rotary head drum 1 are PG signals output from the PG monomulti 9. A head switching pulse (hereinafter, referred to as an HSW signal) for performing the switching of the sub-code including a search signal, a time signal (hour, minute, second), a frame signal, etc. from the PG signal from the PG monomulti 9 A sub code gate creator for creating a gate signal (SCG), 20 is an H from the PG monomulti 9
This is a video circuit to which the SW signal and the SCG signal from the subcode gate creator 14 are input.

The operation of the magnetic recording / reproducing apparatus of the present embodiment configured as described above will be described below.

A pair of magnetic heads are attached to the rotary head drum 1, and record and reproduce video and audio signals on the magnetic tape 2 transported in the direction of arrow B while rotating in the direction of arrow A. The FG sensor 3 detects the rotation frequency of the rotary head drum 1 and amplifies the rotation by the FG amplifier 4, and then sends the amplified signal to the frequency discriminator 5 and the FG selector 16. The frequency discriminator 5 performs AFC control and performs speed control. . The output signal of the frequency discriminator 5 is input to the notch filter 6. The notch filter 6 does not allow a specific frequency to pass, and detects (passes) unevenness of the FG signal for one rotation of the rotary head drum.

FIG. 5 shows the output signal characteristics of the notch filter 6 in this configuration. The rotation frequency of the rotary head drum of the DV format is about 150 [Hz], and as shown in FIG. 5, it has a characteristic of not passing a frequency of 150 [Hz], which is an integral multiple thereof. As described later, the characteristic is such that low-frequency components including the DC component are not passed. Therefore, when the rotation frequency is not 150 [Hz] or a frequency that is an integral multiple of 150 [Hz], a signal is output from the notch filter 6. The signal is output to the mixing circuit 24 as an error voltage.

The output signal of the FG amplifier 4 is supplied to the FG selection unit 16
Is input to the FG selection unit 16 as well.
From the G signals, the FG signal having the phase closest to the HSW signal is selected and output to the terminal a of the second switch 17. The second switch 17 is connected to the terminal a during the special reproduction of the present apparatus, and connected to the terminal b during the recording and reproduction. At the time of special reproduction, the FG selection unit 16 selects the FG having the phase closest to the HSW signal.
The signal is extracted and used as a signal for phase comparison in APC control in the phase comparison unit 10. That is, the rate of change (relative speed correction rate) of the rotation speed of the drum motor during special playback,
Calculated by measuring the period (T _HSW) of HSW signal, by which is adapted to vary the delay amount of the PG multivibrator 9 (T _M) in proportion to the calculated value, the rotation of the rotary head drum 1 This is because a problem such as instability or taking time for stabilization has occurred. In order to break such an unstable factor loop, one of the FG signals output a plurality of times in one rotation of the rotary head drum 1 irrespective of the delay amount ( _TM ) of the PG monomulti 9 is selected and the phases are compared. Used as a signal on the side. This can eliminate the cause of the phase shift.

On the other hand, the rotary head drum 1 is
After the rotation phase is detected and amplified by the PG amplifier 8, the PG monomulti 9 adjusts the PG delay time in order to correct the mounting error between the PG signal and the video head. PG Mono Multi 9
Is sent to the video circuit 20 as the HSW signal 13 and is input to the terminal b of the second switch 17. The second switch 17 is connected to the terminal b during recording and 1 × speed reproduction, and inputs an output signal of the PG monomulti 9 to the phase comparator 10. In the phase comparator 10, the second
And a phase comparison between the signal from the switch 17 and the APC phase reference signal 11, and outputs the error as an error voltage.

The APC reference signal 11 input to the phase comparator 10 includes a reference signal from the internal reference signal generator 21 and
A reference signal input from the outside via the reference signal input unit 22 is obtained by switching with a switch 23. At the time of recording and reproduction, the reference signal from the reference signal input unit 22 is input to the phase comparator 10. During special reproduction, the reference signal from the internal reference signal generator 21 is input to the phase comparator 10.

The error voltage of the AFC system from the notch filter 6 and the error voltage of the APC system from the phase comparator 10 are mixed by the mixing circuit 24 and input to the drive circuit 12. The drive circuit 12 controls the rotation of the rotary head drum 1 based on the error voltage so as to correct the error of the rotation frequency and the rotation phase.

On the other hand, the H output from the PG mono multi 9
The SW signal 13 is input to the video circuit 20 and also to the subcode gate creator 14. The subcode gate creator 14 generates an SCG indicating the subcode recording position on the magnetic tape 2 based on the HSW signal 13.
A signal is created and input to the video circuit 20. The video circuit 20 controls switching of a plurality of magnetic heads provided on the rotary head drum 1 by an HSW signal and controls recording of a subcode at a predetermined position on the magnetic tape 2 by an SCG signal.

FIGS. 2 and 3 are timing charts of the present embodiment. FIG. 2 is a timing chart at the time of recording and in the 1 × speed reproduction mode, and has the same timing as FIG.
In the figure, (a) is an FG signal, (b) is a PG signal,
(C) is the output signal of the PG mono multi, (d) is the HSW signal, and (e) is the APC reference signal. FIG. 3 is a timing chart at the time of special reproduction.
(B) is a PG signal, (c) is an output signal of a PG monomulti, (d) is an HSW signal, (e) is an FG signal closest to a predetermined rising edge of the HSW signal, and (f) is an APC reference signal. .

Here, in the recording and 1 × speed reproduction mode shown in FIG.
The HSW signal output from the PG mono multi 9 (FIG. 2)
(D)) rise and A from the first switch 23
This is the rising edge of the PC reference signal (FIG. 2 (e)).

On the other hand, during the special reproduction shown in FIG. 3, the rising edge of the HSW signal (FIG. 3D) of the FG signal (FIG. 3A) output six pulses per rotation of the rotary head drum 1 3 (e) and the rise of the APC reference signal (FIG. 2 (e)) from the first switch 23 are compared.

The FG signal, PG signal,
Although the output signal of the PG monomulti and the HSW signal are displayed at the same timing, the rotation speed of the rotary head drum 1 is corrected by the relative speed correction in the special reproduction shown in FIG. The periods of (a) the FG signal, (b) the PG signal, (c) the output signal of the PG monomulti, and (d) the HSW signal are all shorter.

As described above, according to the present embodiment, during special playback such as fast forward playback or rewind playback, the phase comparison unit 1
As a signal to be compared in phase with the APC reference signal at 0, HS
Drum 1 not affected by W signal and PG mono multi
By selecting the signal that is closest to the HSW signal among the plurality of FG signals that are output during rotation and comparing the phases, the instability factor loop is broken, and therefore, a stable APC with a fast pull-in operation
Control can be realized.

[0051]

As described above, according to the present invention, during special reproduction such as high-speed search, one rotation of the drum which is not affected by the PG monomulti as the signal to be compared with the phase in the APC control, not the HSW. A plurality of FG pulses which are output at the same time are selected from those having the closest phase to the HSW, and the phases are compared, thereby breaking the loop of the instability factor existing in the APC control and realizing the stable APC control with a fast pull-in operation. be able to.

[Brief description of the drawings]

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

FIG. 2 is a timing chart at the time of recording and at the time of 1 × speed reproduction in the embodiment.

FIG. 3 is a timing chart at the time of special reproduction in the embodiment.

FIG. 4 is a block diagram showing a configuration of a conventional magnetic recording / reproducing apparatus.

FIG. 5 is a characteristic diagram of a notch filter.

FIG. 6 is a schematic view showing a track pattern in a DV format.

FIG. 7 is a timing chart of signals of various parts in a conventional magnetic recording / reproducing apparatus.

FIG. 8 is a schematic diagram showing a track pattern.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 rotating head drum 3 frequency generator sensor 4 FG amplifier 5 frequency discriminator 6 notch filter 7 phase detection sensor 8 PG amplifier 9 PG monomulti 10 phase comparator 12 drive circuit 16 FG selector 17 second switch 23 first switch

Claims (2)

[Claims] A rotating head drum having a magnetic head for recording and reproducing a signal on and from a recording medium; rotating speed detecting means for detecting the rotating speed of the rotating head drum; Speed signal amplifying means for amplifying a rotation speed signal; speed control means for detecting unevenness of the rotation speed signal and outputting a first error signal; and a predetermined speed signal among the speed signals from the speed signal amplifying means. Selecting means for selecting, phase detecting means for detecting a rotational phase of the rotary head drum, phase signal amplifying means for amplifying a rotational phase signal from the phase detecting means, and a phase signal output from the phase signal amplifying means PG mono-multi for adjusting the delay time of the PG mono-multi, and second switching means for selecting either the output signal from the selection means or the output signal from the PG mono-multi. A first switching means for switching and outputting a first reference signal set inside the apparatus and a second reference signal inputted from the outside, and a signal selected by the second switching means, A phase comparison unit that compares the reference signal from the first switching unit and outputs the comparison result as a second error signal; and a first error signal from the speed control unit and a second error signal from the phase comparison unit. 2. A magnetic recording / reproducing apparatus comprising: a mixing unit that mixes the error signals of the second and third error signals; and a driving unit that controls the rotation of the rotary head drum to be corrected based on the error signal mixed by the mixing unit. . 2. The second switching means is provided when the apparatus performs recording or reproduction at the same tape speed as recording.
A magnetic recording / reproducing apparatus which switches to a mono-multi side and switches to a selection means side during special reproduction.