JP3484964B2 - Magnetic recording / reproducing device - Google Patents

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 of digital technology, a DV format VTR capable of digitally recording and reproducing video, audio, system data relating to a tape on a magnetic tape for home video is becoming popular. The conventional technique will be described below.

FIG. 4 is a block diagram showing the structure of a rotary head drum and a control circuit in a conventional magnetic recording / reproducing apparatus. Reference numeral 1 denotes a rotary head drum that has a magnetic head and can rotate to record and reproduce various signals on a magnetic tape 2. Reference numeral 2 denotes a magnetic tape on which various signals are wound around the rotary head drum 1 to record various signals, and 3 denotes a rotary head drum 1. Frequency generator sensor (hereinafter referred to as FG sensor) which is a rotation speed detecting means for detecting the rotation frequency of the FG signal and outputs an FG signal. Reference numeral 4 is a speed signal amplifying means for amplifying the FG signal from the FG sensor 3. The amplifier 5 is a frequency discriminator that extracts a modulation signal from the FG signal from the FG amplifier 4, and 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. In this configuration, the rotary head drum 1 The normal rotation frequency and the rotation frequency that is an integral multiple thereof are not passed, and the rotation error is output as an error voltage. The frequency discriminator 5 and the notch filter 6 constitute a speed control means.

Reference numeral 7 denotes a phase detection sensor (hereinafter referred to as PG) which is a phase detection means for detecting the rotation phase of the rotary head drum 1 and outputting a PG signal, and 8 denotes P from the PG sensor 7.
A PG amplifier which is a phase signal amplifying means for amplifying the G signal,
Reference numeral 9 is a PG monomulti for adjusting the PG delay time of the PG signal, 21 is an internal reference signal generator for generating a first reference signal inside the apparatus, and 22 is a second reference signal input from the outside such as a video signal. The reference signal input section 23 is a switch which is a first switching means for switching the signal from the internal reference signal generating section 21 or the signal from the reference signal input section 23 and outputting the APC reference signal 11. At the time of the special reproduction, it is connected to the side of the reference signal input section 23, and at the time of special reproduction, it is connected to the side of the internal reference signal generation section 21. Reference numeral 10 denotes a phase comparator which compares the phase of the PG signal from the PG mono-multi 9 and the APC reference signal 11 and outputs the error as an error voltage,
Reference numeral 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 drive of the rotary head drum based on the error voltage mixed by the mixing circuit 24. A drive circuit, which is a drive means, 13 is a PG output from the PG mono-multi 9.
A signal, which is a head switching pulse (hereinafter referred to as an HSW signal) for switching a plurality of heads provided on the rotary head drum 1, 14 is a search signal from the PG signal from the PG monomulti 9 or a time signal. Minutes. Seconds. A sub-code gate generator for generating a sub-code gate signal including a frame signal, 20 is an HSW from the PG monomulti 9
This is a video circuit to which the signal and the SCG signal from the subcode gate generator 14 are input.

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

A pair of magnetic heads are attached to the rotary head drum 1, and while rotating in the direction of arrow A, recording / reproduction of a video / audio signal is performed on the magnetic tape 2 transferred in the direction of arrow B. The FG sensor 3 detects the rotation frequency of the rotary head drum 1, is amplified by the FG amplifier 4, and is then sent to the frequency discriminator 5 for automatic frequency control (hereinafter referred to as A
The speed control is performed by performing FC 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.

The output signal characteristic of the notch filter 6 in this configuration is shown in FIG. 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 will be described later, the characteristic is such that low frequency components including DC components also do not pass. Therefore, when the rotation frequency is not a frequency of 150 [Hz] or an integral multiple thereof, the error is output as an error voltage.

On the other hand, the rotary head drum 1 is connected to the PG sensor 7.
The rotation phase of is detected and amplified by the PG amplifier 8, and then the PG mono-multi 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
The output of 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 is compared with the C phase reference signal 11 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 section 22.
A reference signal input via the switch 23, and the reference signal from the reference signal input section 22 is input to the phase comparator 10 at the time of recording and reproduction, and the internal reference is obtained at the time of special reproduction. The reference signal from the signal generator 21 is input to the phase comparator 10.

The AFC system error voltage from the notch filter 6 and the APC system error voltage from the phase comparator 10 are mixed in the mixing circuit 24 and input to the drive circuit 12. Based on the error voltage, the drive circuit 12 controls the rotation of the rotary head drum 1 so as to correct the error in 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 sub code gate creator 14. In the subcode gate generator 14, SC indicating the subcode recording position on the magnetic tape 2 based on the HSW signal 13
A G signal is created and input to the video circuit 20. In the video circuit 20, the rotary head drum 1 is driven by the HSW signal.
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 in.

Next, the relationship of each signal in this apparatus will be described with reference to FIGS. 6 and 7. FIG. 6 is a schematic diagram showing a DV format track pattern, and FIG. 7 is a timing chart of each signal in this apparatus.
In FIG. 6, 51 is a search signal or time signal (hour, minute,
Seconds) and subcode recording areas for recording frame signals, 5
Reference numeral 2 is a video signal recording area in which a video signal is recorded, and 53 is an audio signal recording area in which an audio signal is recorded. See also FIG.
, (A) is an FG signal, (b) is a PG signal,
(C) is an output signal of the PG mono-multi 9, and (d) is HSW.
6, (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 HSW signal (d) is phase-controlled so as to be synchronized with the APC reference signal (g).

The PG signal (FIG. 7B) is converted into the signal of FIG. 7C by the PG monomulti 9, and the HSW signal (FIG. 7) delayed from the PG signal by the time T _{M is} generated based on this signal.
(D)) is made. The DV format is compatible with a high-speed search function for searching for a desired recording position on the magnetic tape 2 at high speed, so that a search signal and a time signal (hour, minute,
Sec), a subcode recording area 51 in which a frame signal is recorded
Is set. Magnetic tape 2 in high-speed search
In order to avoid a read error with the adjacent video signal recording area 52 when reading the subcode signal recorded in the subcode recording area 51, the subcode gate generator 1
At 4, the SCG signal (FIG. 7 (f)) synchronized with the HSW signal (FIG. 7 (d)) is generated so that the subcode signal and the video signal can be 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
Is the first head locus which is the head locus during normal reproduction, 7
Reference numeral 2 is a second head locus that is a head locus during quintuple speed fast reproduction, and 73 is a third head locus that is a head locus during still image reproduction.

As shown by the second and third head loci 72 and 73, the relative speed between the magnetic tape and the magnetic head changes during special reproduction in which the magnetic tape is sent at a speed different from that during recording. This is due to helical scan recording, and 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, the length of one magnetic head scanning period is shortened by four times the step α during the 5 × fast-forward reproduction. Generally, at the n-fold speed, the length L _n of one head scanning period is

[0016]

[Equation 1]

In order to correct this, the number of rotations of the rotary head drum 1 is changed and the correction is performed. Therefore, the correction factor ε (%) of the rotation speed is

[0018]

[Equation 2]

It becomes At this time, the period of the HSW signal (T
_HSW ), FG signal cycle, PG signal cycle, correction factor ε
Changes with.

The number of revolutions of the rotary head drum 1 changes in accordance with the correction rate ε of the number of revolutions of the rotary head drum 1 corresponding to the tape speed, and the period ( _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 when recording, to 60 as the fast-forward reproduction mode.
When changing to double speed, the rotation speed of the rotary head drum 1 is 1
The speed is 111% compared to the double speed. But REW
When the mode changes to -60 times speed, the rotation speed of the rotary head drum 1 becomes 89% of the speed at the 1 times speed, and it takes some time to reach this speed. During the transition period in which the rotation speed of the rotary head drum 1 is changing, the periods T _HSW , FG and PG of the HSW signal change in proportion to the rotation speed, but T _M , 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 reached the target rotation speed yet,
Since the correction rate ε corresponds to the target rotation speed, the magnetic head scans the sub-code recording area 51 at the time of erroneous scanning of the adjacent video signal recording area 52.
The SCG signal may interfere with the video signal recording area 52.

Therefore, during special reproduction in which the tape speed is different from that at the time of recording, the rotational speed of the 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. By measuring the change rate (relative speed correction rate) of the rotation speed of the drum motor during special playback with respect to the rotation speed of the drum motor during recording, the HSW signal cycle ( _THSW ) is measured by the HSW synchronous measurement unit 15. The delay amount ( _TM ) of the PG mono-multi 9 is changed in proportion to the calculated value. Also, like the delay amount of the PG mono-multi 9, the HSW in the SCG signal is
The relative position T _D from the signal and the pulse width T _S were changed.

Further, in addition to the above special reproduction, the same applies to the transition from normal reproduction (1 × speed) to special reproduction, transition from special reproduction to normal reproduction (1 × speed), and transition from special reproduction to special reproduction at a different tape speed. It was solved by making the operation of.

In FIG. 4, reference numeral 15 denotes H for measuring T _HSW.
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 am trying to change.

[0025]

[Equation 3]

Recording and 1 × speed reproduction are input in the phase comparison unit 10 from the video processing block through the reference signal input unit 22 at 150 Hz (NTSC is 1/14).
9.85 [sec], PAL is 1/150 [sec])
Reference signal (external reference) and PG Mono Multi 9
In contrast to the phase comparison with the HSW signal from the internal reference signal generator, the rotational speed of the rotary head drum 1 is different from that at the time of recording and 1 × speed during the special reproduction because of the relative speed correction. The phase of the reference signal (internal reference) from 21 and the HSW signal is compared.

Regarding the AFC control and APC control during special reproduction, the notch filter 6 arranged in the AFC control system in FIG. 4 described above has a characteristic of not passing low frequency components including DC components. In order to compensate for this low frequency error component, the APC control during special reproduction is necessary when the notch filter 6 in the AFC control is present.

[0028]

However, in the above-described conventional configuration, the following problems occur because the APC control is performed by the reference signal (internal reference) and the HSW signal during special reproduction.

As the operation during rewinding reproduction, (1) the rotary head drum 1 is decelerated by the relative speed correction, (2)
The period of the HSW signal becomes long, (3) the T _M value is increased in proportion to the period of the HSW signal, (4) the phase of the HSW signal deviates from the internal reference signal from the internal reference signal generation unit 21, (5) Phase control, (6) Acceleration of rotation of the rotary head drum 1, (7) Shorter cycle of HSW signal, (8) Smaller T _M value in proportion to cycle of HSW signal. , (9) The phase of the HSW signal is deviated from the internal reference signal, (10) the phase control is performed, (11) the deceleration of the rotary head drum 1 is performed, (12) the cycle of the HSW signal becomes long (the above ( Returning to 2)), there is a problem in such an operation that the rotation of T _M and the rotary head drum 1 is not stable or it takes time to stabilize.

Further, in the fast-forward reproduction, it is completely opposite to the rewind reproduction, and (1) the rotation of the rotary head drum 1 is accelerated by the relative speed correction, (2) the cycle of the HSW signal becomes short, (3) ) Decrease the T _M value in proportion to the period of the HSW signal, (4) deviate the phase of the HSW signal from the internal reference signal, (5) perform phase control, (6) decelerate the rotary head drum 1. , (7) the period of the HSW signal becomes long, (8) the T _M value is increased in proportion to the period of the HSW signal, (9) the phase of the HSW signal deviates from the internal reference signal, (10) phase Although the control is performed, (11) the rotation of the rotary head drum 1 is accelerated, and (12) the cycle of the HSW signal is shortened (returns to (2) above). 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 is intended to solve the above-mentioned problems, and a pull-in operation is fast and a stable APC during special reproduction.
An object of the present invention is to provide a magnetic recording / reproducing device capable of performing control.

[0032]

In order to achieve this object, a magnetic recording / reproducing apparatus of the present invention includes a rotating head drum having a magnetic head for recording / reproducing a signal on / from a recording medium, and a rotating head drum. A rotation speed detecting means for detecting the rotation speed, a speed signal amplifying means for amplifying the rotation speed signal detected by the rotation speed detecting means, and a speed control means for detecting unevenness of the rotation speed signal and outputting a first error signal. A selection means for selecting a predetermined speed signal from the speed signals from the speed signal amplification means, a phase detection means for detecting the rotation phase of the rotary head drum, and a phase signal amplification for amplifying the rotation phase signal from the phase detection means. Means, a PG mono-multi for adjusting the delay time of the phase signal output from the phase signal amplifying means, and an output signal from the selecting means or an output signal from the PG mono-multi. A second switching means for selecting,
First switching means for switching and outputting a first reference signal set inside the apparatus and a second reference signal input from the outside, a signal selected by the second switching means, and a first reference signal. A phase comparison section for comparing the reference signal from the switching means and outputting the comparison result as a second error signal, a first error signal from the speed control means and a second error signal from the phase comparison section. And a drive means for controlling so as to correct the rotation of the rotary head drum based on the error signal mixed by the mixing means.

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

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic recording / reproducing apparatus according to the first and second aspects of the present invention includes a rotating head drum having a magnetic head for recording / reproducing signals on / from a recording medium,
Rotation speed detection means for detecting the rotation speed of the rotary head drum, speed signal amplification means for amplifying the rotation speed signal detected by the rotation speed detection means, and detection of unevenness of the rotation speed signal to output a first error signal. Speed control means, selection means for selecting a predetermined speed signal from the speed signals from the speed signal amplification means, phase detection means for detecting the rotation phase of the rotary head drum, and amplification of the rotation phase signal from the phase detection means. Phase signal amplifying means, a PG mono-multi for adjusting the delay time of the phase signal output from the phase signal amplifying means, and recording or reproduction at the same tape speed as during recording.
Sometimes switch to the PG mono-multi side, and during special playback
Is a second switching means for switching to the selection means side ,
First switching means for switching and outputting a first reference signal set inside the apparatus and a second reference signal input from the outside, a signal selected by the second switching means, and a first reference signal. A phase comparison section for comparing the reference signal from the switching means and outputting the comparison result as a second error signal, a first error signal from the speed control means and a second error signal from the phase comparison section. And a driving means for controlling so as to correct the rotation of the rotary head drum based on the error signal mixed by the mixing means. With this configuration, during special reproduction such as high-speed search, APC
By selecting the signal closest to the rising timing of the HSW signal as the signal on the phase comparison side of the control and performing the phase comparison, stable APC control with a fast pull-in operation can be realized.

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram showing the configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. In FIG.
Is a rotary head drum having a magnetic head and capable of rotating to record and reproduce various signals on the magnetic tape 2. Reference numeral 2 is a magnetic tape on which various signals are wound around the rotary head drum 1 to record various signals, and 3 is a rotary head drum 1. Rotation frequency is detected and F
An FG sensor which is a rotation speed detecting means for outputting a G signal,
Reference numeral 4 is an FG amplifier which is a speed signal amplifying means for amplifying the FG signal from the FG sensor 3, and 5 is an FG from the FG amplifier 4.
A frequency discriminator for extracting a modulation signal from the signal, 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 in this configuration, a normal rotation frequency of the rotary head drum 1 and an integral multiple thereof. The rotation frequency is not passed, and the signal passed through this filter is a rotation error and is output to the mixing circuit 24 as an error voltage. This frequency discriminator 5 and notch filter 6
And constitute speed control means.

Reference numeral 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 that adjusts the PG delay time of the PG signal, and 16 is F during special playback.
An FG selection unit that is a selection unit that selects an FG signal of the phase closest to the HSW signal from the FG signals from the G amplifier 4.
Reference numeral 17 is a second switch which is a second switching means for switching the signal input to the phase comparator 10 at the time of recording and 1 × speed reproduction and at the time of special reproduction, and is connected to the terminal b side at the time of recording and 1 × speed reproduction. , It is connected to the terminal a side during special playback. 21
Is an internal reference signal generator for generating a first reference signal inside the apparatus, 22 is a reference signal input unit for inputting a second reference signal from the outside such as a video signal, and 23 is an internal reference signal generator 21. A first switch, which is a first switching means for switching between a signal and a signal from the reference signal input section 23 and outputting the APC reference signal 11, is connected to the reference signal input section 23 side during recording and reproduction, During reproduction, it is connected to the internal reference signal generator 21 side.

10 is a signal from the second switch 17 and A
A phase comparator that compares the phase with the PC reference signal 11 and outputs the error as an error voltage, and 24 is a notch filter 6
Mixing circuit, which is a mixing means for mixing the error voltage from the phase comparator 10 and the error voltage from the phase comparator 10, 12 is the mixing circuit 2
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, and 13 is a plurality of heads provided on the rotary head drum 1, which are PG signals output from the PG monomulti 9. A head switching pulse (hereinafter referred to as an HSW signal) for switching the sub-code, 14 is a subcode including a search signal, a time signal (hour, minute, second), a frame signal, etc. from the PG signal from the PG monomulti 9. Sub-code gate generator for generating gate signal (SCG), 20 is H from PG monomulti 9
This is a video circuit to which the SW signal and the SCG signal from the subcode gate generator 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 recording / reproduction of a video / audio signal is performed on the magnetic tape 2 transferred 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, is amplified by the FG amplifier 4, and is then sent to the frequency discriminator 5 and the FG selector 16. The frequency discriminator 5 performs AFC control and speed control. . The output signal of the frequency discriminator 5 is input to the notch filter 6. The notch filter 6 does not pass a specific frequency, and detects (passes) unevenness of the FG signal for one rotation of the rotary head drum.

The output signal characteristic of the notch filter 6 in this configuration is shown in FIG. 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 will be described later, the characteristic is such that low frequency components including DC components also do not pass. Therefore, when the rotation frequency is not 150 [Hz] or a frequency that is an integral multiple thereof, the notch filter 6 outputs a signal. The signal is output to the mixing circuit 24 as an error voltage.

The output signal of the FG amplifier 4 is the FG selector 16
Is also input to the FG selection unit 16
Of 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 side at the time of special reproduction of this apparatus and is connected to the terminal b side at the time of recording / reproduction. During special reproduction, the FG selector 16 causes the FG having the phase closest to the HSW signal.
The signal is extracted and used as a signal for phase comparison of APC control in the phase comparison unit 10. It is the change rate (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 problems such as instability or time required for stabilization have occurred. In order to break such an instability factor loop, one of a plurality of FG signals output for one rotation of the rotary head drum 1 irrespective of the delay amount ( _TM ) of the PG monomulti 9 is selected for phase comparison. It is used as a side signal. As a result, the factor of phase shift can be eliminated.

On the other hand, the rotary head drum 1 is connected to the PG sensor 7.
The rotation phase of is detected and amplified by the PG amplifier 8, and then the PG mono-multi 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
The output of is sent to the video circuit 20 as the HSW signal 13, and is also input to the terminal b of the second switch 17. The second switch 17 is connected to the terminal b side during recording and 1 × speed reproduction, and inputs the output signal of the PG mono-multi 9 to the phase comparator 10. In the phase comparator 10, the second
The signal from the switch 17 and the APC phase reference signal 11 are compared in phase, and the error is output as an error voltage.

The APC reference signal 11 input to the phase comparator 10 is the same as the reference signal from the internal reference signal generator 21.
The reference signal input from the outside via the reference signal input unit 22 is obtained by switching with the switch 23. During 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 AFC error voltage from the notch filter 6 and the APC error voltage from the phase comparator 10 are mixed by the mixing circuit 24 and input to the drive circuit 12. Based on the error voltage, the drive circuit 12 controls the rotation of the rotary head drum 1 so as to correct the error in 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 the subcode gate generator 14. The sub-code gate generator 14 is an SCG indicating the sub-code 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 the HSW signal, and controls recording of a subcode at a predetermined position on the magnetic tape 2 by the SCG signal.

2 and 3 are timing charts of this embodiment. FIG. 2 is a timing chart at the time of recording and the 1 × speed reproduction mode, which has the same timing as FIG. 7.
In the figure, (a) is an FG signal, (b) is a PG signal,
(C) is an output signal of PG monomulti, (d) is an HSW signal, and (e) is an APC reference signal. FIG. 3 is a timing chart at the time of special reproduction, (a) is an FG signal,
(B) is a PG signal, (c) is a PG mono-multi output signal, (d) is an HSW signal, (e) is an FG signal closest to a predetermined rise of the HSW signal, and (f) is an APC reference signal. .

In the recording and 1 × speed reproduction mode shown in FIG.
The HSW signal output from the PG mono-multi 9 (see FIG.
(D)) rising edge 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 HSW signal (FIG. 3 (d)) rises out of the FG signal (FIG. 3 (a)) output for 6 pulses for one rotation of the rotary head drum 1. The closest rising edge (Fig. 3 (e)) to the rising edge of the APC reference signal (Fig. 2 (e)) from the first switch 23 are compared.

It should be noted that the FG signal, the PG signal of FIG. 2 and FIG.
Although the output signal of the PG mono-multi 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 during the special reproduction shown in FIG. The respective cycles are shorter for the (a) FG signal, (b) PG signal, (c) PG mono-multi output signal, and (d) HSW signal.

As described above, according to the present embodiment, the phase comparison unit 1 is used during special reproduction such as fast-forward reproduction and rewind reproduction.
As the signal whose phase is compared with the APC reference signal at 0, HS
Drum 1 not affected by PG mono-multi, not W signal
Of the FG signals output for rotation, the one closest to the HSW signal is selected and phase comparison is performed to break the loop of the instability factor, and thus 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 influenced by PG mono-multi instead of HSW as a signal on the phase comparison side of APC control. By selecting the FG pulse that has the closest phase to HSW from among the plurality of FG pulses output to, and comparing the phases, the instability factor loop existing in the APC control is cut off, and stable APC control with fast pull-in operation is realized. be able to.

[Brief description of 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 1 × speed reproduction in the embodiment.

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

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

FIG. 5: Notch filter characteristic diagram

FIG. 6 is a schematic diagram showing a DV format track pattern.

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

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

[Explanation of symbols]

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 Mono Multi 10 Phase comparator 12 Drive circuit 16 FG selection section 17 Second switch 23 First switch

Claims (2)

(57) [Claims] 1. A rotating head drum having a magnetic head for recording and reproducing a signal on a recording medium, a rotating speed detecting means for detecting a rotating speed of the rotating head drum, and a rotating speed detecting means for detecting the rotating speed. A speed signal amplifying means for amplifying the rotation speed signal, a 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. Selection means for selecting, phase detection means for detecting the rotation phase of the rotary head drum, phase signal amplification means for amplifying the rotation phase signal from the phase detection means, and phase signal output from the phase signal amplification means PG mono-multi that adjusts the delay time of the recording, and the same tape when recording or during recording
When playing back at speed, switch to the PG mono-multi side
The second mode of switching to the selection means side during special reproduction
The switching means, the first switching means for switching and outputting the first reference signal set inside the apparatus and the second reference signal input from the outside, and the second switching means are selected. A phase comparison unit for comparing the signal and the reference signal from the first switching unit and outputting the comparison result as a second error signal; a first error signal from the speed control unit and the phase comparison unit; And a drive means for controlling so as to correct the rotation of the rotary head drum based on the error signal mixed by the mixing means. Recording / playback device. Wherein said second switching means, when the apparatus is reproduced at the same tape speed as during recording or recording
Is switched to the PG multivibrator side, during special reproduction switched to the <br/> selection means side, said selection means the PG monomer
The speed signal closest to the output signal timing from the latch
Select claim 1, wherein the to the phase comparator
Magnetic recording and reproducing apparatus.