JP3484967B2 - 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 a magnetic recording / reproducing apparatus which is effectively used for a helical scan type digital video tape recorder such as a DV format.

[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.
Hereinafter, a conventional magnetic recording / reproducing apparatus will be described with reference to the drawings.

FIG. 5 is a block diagram of a rotary head drum of a helical scan type VTR and a control circuit as an example of a conventional magnetic recording / reproducing apparatus. Reference numeral 1 denotes a rotary head drum which has a magnetic head and rotates at a predetermined rotation speed to record a video / audio signal or the like on a magnetic tape 2. Reference numeral 2 denotes a magnetic head wound around the rotary head drum 1 at a predetermined angle to record a video / audio signal or the like. A magnetic tape, a frequency generator sensor (hereinafter, referred to as an FG sensor) 3 is a rotation speed detection unit that detects a rotation frequency (rotation speed) of the rotary head drum 1 and outputs an FG signal, and 4 is from the FG sensor 3. FG amplifier 5 which is a speed signal amplifying means for amplifying the FG signal of
A frequency discriminator that extracts a modulation signal from the FG signal from the FG signal and outputs the remaining signal as an error voltage, 6 is a rotation phase sensor (hereinafter referred to as a phase detection unit that detects a rotation phase of the rotary head drum 1 and outputs a PG signal). , PG sensor), 7 is a PG amplifier which is a phase signal amplifying means for amplifying the PG signal from the PG sensor 6, and 8 is a PG mono-multi (hereinafter referred to as PG mono-multi) which adjusts the PG delay time to correct a mounting error of the magnetic head. , PGMM) 10 is a reference signal generator that generates a phase reference signal, 9 is a phase comparison between the output signal from the PGMM 8 and the reference signal from the reference signal generator 10, and the error is output as an error voltage. Is a phase comparator, 16 is a mixing circuit which is a mixing means for mixing the error voltage from the frequency discriminator 5 and the error voltage from the phase comparator 9, and 11 is a mixing circuit. Drive circuit is a drive unit for driving and controlling the rotation of the rotary head drum 1 so as to correct the error based on the error voltage from the road 16, 12 PGMM
8 head switching pulse (hereinafter, HSW
, 13 is a sub-code gate creator which is a sub-code gate creating means for creating a sub-code gate pulse (hereinafter referred to as SCG) based on the HSW 12.

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 so that a video / audio signal or the like can be recorded or reproduced on the magnetic tape 2 transported in the direction of arrow B while rotating in the direction of arrow A. . The rotation speed of the rotating rotary head drum 1 is detected by the FG sensor 3, the rotation speed signal is amplified by the FG amplifier 4, and then sent to the frequency discriminator 5. The frequency discriminator 5 extracts the modulation signal from the rotation speed signal from the FG amplifier 4 and outputs the remaining signal as an error voltage to the mixing circuit 16.

On the other hand, the PG sensor 6 is the rotary head drum 1
The rotation phase signal is detected and the rotation phase signal is detected by the PG amplifier 7.
It is output to PGMM8 after being amplified by. In PGMM8,
In order to correct the rotation phase and the mounting error of the magnetic head,
The PG delay time of the rotation phase signal is adjusted. The output signal of the PGMM 8 is output to the phase comparator 9 as well as HS.
It is also output to the sub-code gate generator 13 as a W signal. The phase comparator 9 compares the phase of the signal from the PGMM 8 with the reference signal from the reference signal generator 10, and outputs the error resulting from the comparison as an error voltage to the mixing circuit 16.

AF from the frequency discriminator 5 in the mixing circuit 16
The C system error voltage and the APC system error voltage from the phase comparator 9 are mixed and output to the drive circuit 11. The drive circuit 11 controls the rotation of the rotary head drum 1 so as to correct the error component by the error voltage.

The output signal of the PGMM 8 is input to the subcode gate generator 13 as the HSW signal 12, and the subcode gate generator 13 outputs the subcode gate pulse (SC) indicating the subcode recording position on the magnetic tape 2.
G) is created.

FIG. 6 is a schematic diagram showing a DV format track pattern. FIG. 7 is a timing chart showing signals of various parts in the conventional magnetic recording / reproducing apparatus.
In FIG. 6, 51 is a search signal or time signal (hour, minute,
Subcode recording area which is a first recording area where a frame signal is recorded, 52 is a video signal recording area which is a second recording area where a video signal is recorded, and 53 is audio where an audio signal is recorded. This is a signal recording area. In FIG. 7, (a) is a PG signal detected by the PG sensor 6, and (b) is P
Signal for delay control in GMM8, (c) is PGM
The HSW signal output from M8, (d) is the SCG signal created by the subcode gate creator 13, and (e) is the timing chart of the track pattern.

In FIG. 7, P detected by the PG sensor 6
From the G signal (a), the HSW signal (c) delayed by the delay control signal (b) in the PGMM by the time T _{M is} generated. In the DV format, in order to support a high-speed search function for searching for a desired recording position on the magnetic tape at high speed, as shown in FIG.
A subcode recording area 51 for recording frame signals (minutes, seconds, etc.) is provided. At the time of high-speed search, in order to avoid a reading error with the adjacent video signal recording area, the SCG signal shown in FIG. 7D synchronized with the HSW signal shown in FIG. And the video signal can be separated. In FIG. 7, SCG
The signal is the delay time T _D and SC from the edge of the HSW signal.
It is created by setting the G pulse width T _S.

FIG. 8 is a schematic diagram showing a track pattern of a helical scan VTR. In the figure, 71 is a head scanning locus during normal recording / reproducing, 72 is a head scanning locus during 5 × fast-forward reproducing, and 73 is a head scanning locus during still image reproducing. During special reproduction (72 and 73 in FIG. 8) in which the tape is sent at a speed different from that during recording, the relative speed of the tape and head changes. This is due to helical scan recording, and adjacent tracks are recorded with a level difference of α as shown in the figure. For example, at the fast-forward 5 × speed indicated by the head scanning locus 72, the length of one head scanning period is reduced by α of four times. Generally, at the n-fold speed, the length L _n of one head scanning period is

[0012]

[Equation 1]

[0013] In order to correct this, the number of rotations of the rotary head drum 1 is changed and correction is performed. Correction factor ε at this time
(%) Is

[0014]

[Equation 2]

[0015] At this time, the period of the HSW signal, FG
The signal period and the PG signal period also change in proportion to the correction factor ε.

FIG. 9 shows a PG signal (a), a PGMM delay control signal (b), and an HS during normal recording / reproduction (1 × speed).
FIG. 10 is a timing chart of the W signal (c), FIG. 10 is a timing chart of the PG signal (a) in the forward fast search (FF), the delay control signal (b) of the PGMM, and the HSW signal (c). PG signal (a) and PG in search (REW) and reverse high-speed search (REW)
It is a timing chart of the delay control signal (b) and HSW signal (c) of MM. FIG. 12 is a timing chart of the DV track pattern (a), the HSW signal (b), and the SCG signal (c) during normal recording / reproduction (1 × speed), and FIG.
3 is a DV track pattern (a), HSW signal (b), and SCG signal (c) at the time of forward fast search (FF).
14 is a timing chart of the DV track pattern (a) and HS during reverse high speed search (REW).
It is a timing chart of a W signal (b) and an SCG signal (c).

As shown in FIGS. 9 to 14, the number of revolutions of the rotary head drum 1 changes in proportion to the correction rate ε corresponding to the tape speed, as can be seen from the PG signal, and the cycle of the HSW signal also changes. Change. Also, the time delay T _M due to PGMM, the delay time T _D from the edge of the HSW signal,
Similarly, the subcode pulse width T _S is controlled in proportion to the correction factor ε.

[0018]

However, in the above-mentioned conventional configuration, for example, when the tape speed changes from the same 1 × speed as during recording to + 60 × speed in the FF mode,
The rotational speed of the rotary head drum 1 is 11 times that at the time of 1 × speed.
When the speed becomes 1% and the speed changes to −60 times as REW mode, the rotation speed of the rotary head drum 1 becomes 89% of the speed at 1 × speed, and it takes some time to reach these speeds. Need. During the transitional period when the rotation speed of the rotary head drum 1 is changing, the HSW cycle T _H , the FG cycle, and the PG cycle change in proportion to the rotation speed, but T _M , T _D , and T _S change when the mode changes. , When the rotation of the rotary head drum 1 starts to accelerate or decelerate, that is, before the drum rotation speed has not reached the target rotation speed yet, the correction rate ε corresponding to the target rotation speed is switched to. Sometimes, when the magnetic head scans the subcode recording area, the adjacent video signal recording area is erroneously scanned, or the SCG signal is recorded while overlapping the video signal recording area during recording.

In view of the above point, the present invention erroneously scans an adjacent video signal recording area when the magnetic head scans the subcode recording area during reproduction, or the SCG signal overlaps the video signal recording area during recording. It is an object of the present invention to provide a magnetic recording / reproducing apparatus capable of preventing the recording.

[0020]

In order to solve the above problems, a magnetic recording / reproducing apparatus of the present invention has a rotating head drum having a magnetic head for recording / reproducing signals on / from a recording medium, and a rotating head drum. Rotation speed detecting means for detecting the rotation speed of the rotation speed detecting means, speed signal amplifying means for amplifying the rotation speed signal detected by the rotation speed detecting means, and a modulation signal extracted from the rotation speed signal and the remaining signal is output as a first error signal. Frequency discriminator, 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 delay time of the phase signal output from the phase signal amplification means And a phase comparator for comparing the output signal of the PG mono-multi and the reference signal and outputting the comparison result as a second error signal; Mixing means for mixing the first error signal from the several discriminator and the second error signal from the phase comparator, and controlling to correct the rotation of the rotary head drum based on the error signal mixed by the mixing means Drive means,
Subcode gate creating means for creating a subcode gate signal based on the output signal of the PG mono-multi, and at the time of recording
Recording during special playback when sending tapes at different tape speeds
Drive during special playback against the rotation speed of the drum motor during
The change rate of the rotation speed of the motor is calculated from the PG mono-multi.
Calculated by measuring the cycle of the output signal of
And the delay amount of the PG multivibrator in proportion to detection value, and the relative position with respect to the PG multivibrator output signal of the subcode gate signal in the subcode gate forming means,
And a period measurement correction factor calculating means for controlling the pulse width of the sub-code gate signal .

With the above structure, when the magnetic head scans the subcode recording area during reproduction, the adjacent video signal recording area is erroneously scanned, or the SCG signal is recorded while overlapping the video signal recording area during recording. It is an object of the present invention to provide a magnetic recording / reproducing device capable of preventing such a situation.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION According to the first to fourth aspects of the present invention, a rotating head drum having a magnetic head for recording and reproducing a signal on a recording medium, and a rotating speed of the rotating head drum are detected. Rotation speed detecting means, speed signal amplifying means for amplifying the rotation speed signal detected by the rotation speed detecting means, and a frequency discriminator for extracting a modulation signal from the rotation speed signal and outputting the remaining signal as a first error signal. , A phase detection means for detecting the rotation phase of the rotary head drum, a phase signal amplification means for amplifying the rotation phase signal from the phase detection means, and a PG mono for adjusting the delay time of the phase signal output from the phase signal amplification means. And a phase comparator for comparing the output signal of the PG mono-multi and the reference signal and outputting the comparison result as a second error signal, and a first error signal from the frequency discriminator. Mixing means for mixing the signal and the second error signal from the phase comparator, driving means for controlling the rotation of the rotary head drum based on the error signal mixed by the mixing means, and output of PG monomulti A sub-code gate creating means for creating a sub-code gate signal based on the signal and a tape at a tape speed different from that at the time of recording.
Rotation speed of the drum motor during recording during special playback
Rate of rotation speed of drum motor during special reproduction for
To measure the cycle of the output signal from the PG mono-multi
Calculated by the delay amount of the PG multivibrator in proportion to the calculated value, the PG multivibrator output of the subcode gate signal in the subcode gate creating means
The relative position to the signal and the pulse of the subcode gate signal.
And a period measurement correction rate calculation means for controlling so as to change the track width, and with this configuration, the drum relative speed is corrected when the tape speed is reproduced at a tape speed different from that at the time of recording, or the transient in which the drum rotation speed is changing. In the period, by measuring the period of the HSW signal or the FG signal and observing the rotation speed of the rotary head drum, the relative speed correction rate corresponding to the rotation speed of the rotary head drum can be calculated. If the delay time of the PGMM, the relative position of the SCG signal from the HSW signal, and the pulse width are changed based on the relative speed correction rate calculated from this rotation speed,
Even when the rotational speed of the rotary head drum has not reached the target rotational speed yet, when the magnetic head scans the subcode area, the adjacent video signal recording area is erroneously scanned, or the SCG signal is the video signal. It is possible to prevent overlapping with the recording area.

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 the present embodiment. Reference numeral 1 denotes a magnetic head having a magnetic head and rotating at a predetermined rotation speed to record a video / audio signal or the like on a magnetic tape 2. Rotating head drum 2 and rotating head drum 1
A magnetic tape on which video and audio signals are recorded by a magnetic head wound at a predetermined angle, 3 is an FG sensor which is a rotation speed detecting means for detecting the rotation frequency (rotation speed) of the rotary head drum 1 and outputting an FG signal, 4 Is an FG amplifier which is a speed signal amplifying means for amplifying the FG signal from the FG sensor 3, 5 is a frequency discriminator for extracting a modulation signal from the FG signal from the FG amplifier 4, and outputting the remaining signal as an error voltage, 6 is a rotation The rotation phase of the head drum 1 is detected and P
A PG sensor which is a phase detecting means for outputting a G signal, 7 is a PG amplifier which is a phase signal amplifying means for amplifying the PG signal from the PG sensor 6, and 8 is a PG delay time for correcting a mounting error of the magnetic head. PGMM, 10 is a reference signal generator that generates a phase reference signal, and 9 is a PGMM
The phase comparator compares the output signal from 8 and the reference signal from the reference signal generator 10 and outputs the error as an error voltage. Reference numeral 16 indicates the error voltage from the frequency discriminator 5 and the phase comparator 9. Mixing circuit which is a mixing means for mixing with the error voltage of 11 and 11 is a driving circuit which is a driving means for driving and controlling the rotation of the rotary head drum 1 so as to correct the error based on the error voltage from the mixing circuit 16.
Is the HSW signal output from the PGMM8, and 13 is the HSW signal
12 is a sub-code gate creator that is a sub-code gate creating means for creating an SCG signal based on 12. Reference numeral 14 denotes a cycle measurement correction rate calculator which is a cycle measurement correction rate calculation means for measuring the HSW signal cycle and calculating a correction rate. The cycle measurement correction rate calculator 14 measures the cycle of the HSW signal and rotates during special reproduction. The PGMM delay time according to the number of revolutions of the head drum 1 at each time, the correction position of the relative position of the SCG signal with respect to the HSW signal, and the correction rate of the width are calculated, and are input to the PGMM 8 and the sub-code gate generator 13.

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 so that a video / audio signal or the like can be recorded or reproduced on the magnetic tape 2 transferred in the direction of arrow B while rotating in the direction of arrow A. . The rotation speed of the rotating rotary head drum 1 is detected by the FG sensor 3, the rotation speed signal is amplified by the FG amplifier 4, and then sent to the frequency discriminator 5. The frequency discriminator 5 extracts the modulation signal from the rotation speed signal from the FG amplifier 4 and outputs the remaining signal as an error voltage to the mixing circuit 16.

On the other hand, the PG sensor 6 is the rotary head drum 1.
The rotation phase signal is detected and the rotation phase signal is detected by the PG amplifier 7.
It is output to PGMM8 after being amplified by. In PGMM8,
In order to correct the rotation phase and the mounting error of the magnetic head,
The PG delay time of the rotation phase signal is adjusted. The output signal of the PGMM 8 is output to the phase comparator 9 as well as HS.
It is also output as a W signal to the sub-code gate generator 13 and the period measurement correction factor calculator 14. In the phase comparator 9, P
The signal from the GMM 8 and the reference signal from the reference signal generator 10 are phase-compared, and the error generated as a result of the comparison is output to the mixing circuit 16 as an error voltage.

AF from the frequency discriminator 5 in the mixing circuit 16
The C system error voltage and the APC system error voltage from the phase comparator 9 are mixed and output to the drive circuit 11. The drive circuit 11 controls the rotation of the rotary head drum 1 so as to correct the error component by the error voltage.

The output signal of the PGMM 8 is input to the subcode gate generator 13 as the HSW signal 12, and the subcode gate generator 13 outputs the subcode gate pulse (SC) indicating the subcode recording position on the magnetic tape 2.
G) is created. Further, the HSW signal from the PGMM 8 is also input to the period measurement correction rate calculator 14, and the period of the HSW signal is measured during special reproduction to calculate the PGMM delay time according to the number of revolutions of the rotary head drum 1 at that time. Then P
Input to GMM8. Furthermore, SCG for HSW signal
The correction factor of the relative position and the relative width of the signal is calculated and input to the subcode gate generator 13.

The rotation speed control of the rotary head drum 1 during special reproduction in the present embodiment will be described in detail below with reference to FIG.

FIG. 2 is a timing chart showing an example of transition from normal reproduction (+ 1 × speed) to FF mode (+ 60 × speed) and transition from FF mode (+ 60 × speed) to normal reproduction (+ 1 × speed). The vertical axis shows the drum speed and PG
The MM delay time, the relative position of the SCG with respect to the HSW signal, and the correction ratio of the pulse width are shown, and the horizontal axis shows the time. In FIG. 2, 21a and 21b are correction rate characteristics in the present embodiment, 22a and 22b are actual rotation characteristics of the rotary head drum 1 based on the correction rate characteristics in the present embodiment, and 23a and 23b are correction rates in the conventional configuration. It shows the characteristics.

At +1 speed at T1 in FIG. 2, the rotational speed of the rotary head drum 1 is about 149.9 [rps], and the correction factor is 1. From this state, the mode shifts to the FF mode, and the drum motor accelerates toward +60 times speed. +6 shown in T2
At the time of reaching 0x speed, the rotational speed of the rotary head drum 1 is about 1
The value is 65.9 [rps], and the correction factor is 1.107. In the prior art, although the rotational speed of the rotary head drum 1 does not reach the target 165.9 [rps] at the instant T1 when the normal reproduction mode (+ 1 × speed) is switched to the FF mode (+ 60 × speed). Instead, the correction factor changes to 1.107 as shown by the correction factor characteristic 23a in FIG. On the other hand, in the present embodiment, the actual rotation of the rotary head drum 1 is regarded as the cycle of the HSW signal, and the correction factor characteristic 22a
Since the correction rate corresponding to the rotation speed is calculated as shown in, it is possible to correct the PGMM delay time, the relative position of the SCG signal with respect to the HSW signal, and the width.

Similarly, at the instant T3 when the FF mode (+60 times speed) is switched to the normal reproduction mode (+1 times speed), the drum rotation speed is conventionally 149.9 [rps] as shown in the correction rate characteristic 23b. ], The correction factor has changed to 1, but in the present embodiment,
As shown in the correction rate characteristic 21b, the PGMM delay time, HS, and the correction rate characteristic are close to the rotation speed characteristic of the rotary head drum 1.
The relative position and relative width of the SCG signal with respect to the W signal can be corrected.

FIG. 3 shows the characteristics when shifting from the normal reproduction mode (+ 1 × speed) to the REW mode (−60 × speed) and from the REW mode (−60 × speed) to the normal reproduction mode (+ 1 × speed). It is a timing chart. The vertical axis represents the drum rotation speed and the correction rate, and the horizontal axis represents time. In FIG. 3, 31a and 31b are correction rate characteristics in the present embodiment, 32a and 32b are actual rotation characteristics of the rotary head drum 1 based on the correction rate characteristics in the present embodiment, 33
Reference characters a and 33b show correction factor characteristics in the conventional configuration.

At + 1 × speed, the number of rotations of the rotary head drum 1 is about 149.9 [rps], and the correction factor is 1. Next, the state is changed to REW mode from this state, and the magnetic tape is -6
When the speed reaches the 0-fold speed, the rotation speed of the rotary head drum 1 is about 133.2 [rps], and the correction rate is 0.889.
In the conventional configuration, the instant T4 at which the normal reproduction mode (+1 speed) is switched to the REW mode (-60 speed)
In addition, the rotational speed of the rotary head drum 1 is 133.2 which is the target.
The correction factor is 0.8 even though it has not reached [rps].
It has changed to 89 (correction factor characteristic 33a in FIG. 3). On the other hand, in the present embodiment, as shown in the correction rate characteristic 31a, the actual rotation of the rotary head drum 1 is regarded as the cycle of the HSW signal, and the correction rate corresponding to the rotation speed is calculated. Time, SCG for HSW
The relative position and width of can be corrected.

Similarly, at the instant T5 at which the REW mode (-60 times) is switched to the normal reproduction mode (+1 times speed), similarly, in the conventional configuration, the rotational speed of the rotary head drum 1 reaches the target 149.9 [rps]. Although it has not reached the limit, the correction factor changes to 1 (correction factor characteristic 33b in FIG. 3). On the other hand, in the present embodiment, as shown in the correction rate characteristic 31b, the correction rate characteristic 31b having a characteristic close to the actual rotation characteristic 32b of the rotary head drum 1 is calculated.
It is possible to correct the GMM delay time, the relative position of the SCG signal with respect to the HSW signal, and the width.

As described above, in the present embodiment, the rotation speed of the drum motor is changed in order to correct the relative speed change between the magnetic head and the magnetic tape during special reproduction in which the tape is sent at a tape speed different from that during recording. A cycle measurement correction rate calculator 14 is provided, and the rate of change of the rotation speed of the drum motor during special reproduction with respect to the rotation speed of the drum motor during recording (relative speed correction rate) is calculated by measuring the cycle of the HSW signal. The amount of delay in the PGMM 8 is changed in proportion to the calculated value.

(Second Embodiment) The second embodiment of the present invention will be described below.

FIG. 4 is a block diagram showing the structure of the magnetic recording / reproducing apparatus of this embodiment. In FIG. 4, reference numeral 1 denotes a rotary head drum having a magnetic head and rotating at a predetermined rotation speed to record a video / audio signal or the like on a magnetic tape 2. Reference numeral 2 denotes a magnetic head wound around the rotary head drum 1 at a predetermined angle and the like. Is recorded on the magnetic tape, 3 is an FG sensor which is a rotational speed detecting means for detecting the rotational frequency (rotational speed) of the rotary head drum 1 and outputs an FG signal, and 4 is an FG sensor.
An FG amplifier, which is a speed signal amplifying means for amplifying the FG signal from the sensor 3, 5 is a frequency discriminator that extracts a modulation signal from the FG signal from the FG amplifier 4 and outputs the remaining signal as an error voltage, and 6 is a rotary head drum PG which is a phase detecting means for detecting the rotation phase of 1 and outputting a PG signal
A sensor, 7 is a PG amplifier which is a phase signal amplifying means for amplifying the PG signal from the PG sensor 6, and 8 is a PG for adjusting the PG delay time in order to correct a mounting error of the magnetic head.
MM, 10 is a reference signal generator that generates a phase reference signal,
Reference numeral 9 is a phase comparator for phase comparison between the output signal from the PGMM 8 and the reference signal from the reference signal generator 10 and outputting the error component as an error voltage. 16 is an error voltage from the frequency discriminator 5 and a phase comparator. A mixing circuit that is a mixing unit that mixes the error voltage from 9 and a drive circuit that is a driving unit that controls the rotation of the rotary head drum 1 so as to correct the error based on the error voltage from the mixing circuit 16. , 12 are HSW signals output from PGMM8,
Reference numeral 13 is a subcode gate creator which is a subcode gate creating means for creating an SCG based on the HSW signal 12.
Reference numeral 14 is a cycle measurement correction rate calculator which is a cycle measurement correction rate calculator for measuring the FG signal cycle output from the FG amplifier 4 and calculating a correction rate. The PGMM delay time according to the number of revolutions of the rotary head drum 1
The correction rate of the relative position and width of the SCG signal with respect to the FG signal is calculated, and the PGMM 8 and the sub code gate generator 13 are calculated.
Send to. The rotation speed of the rotary head drum 1 is FG.
The same effect can be obtained by measuring and using the PG signal period instead of the signal period.

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 so that a video / audio signal or the like can be recorded or reproduced on the magnetic tape 2 transported in the direction of arrow B while rotating in the direction of arrow A. . The rotation speed of the rotating rotary head drum 1 is detected by the FG sensor 3, the rotation speed signal is amplified by the FG amplifier 4, and then sent to the frequency discriminator 5 and the period measurement correction factor calculator 14. F in the frequency discriminator 5
The modulation signal is extracted from the rotation speed signal from the G amplifier 4, and the remaining signal is output to the mixing circuit 16 as an error voltage.

On the other hand, the PG sensor 6 is the rotary head drum 1.
The rotation phase signal is detected and the rotation phase signal is detected by the PG amplifier 7.
It is output to PGMM8 after being amplified by. In PGMM8,
In order to correct the rotation phase and the mounting error of the magnetic head,
The PG delay time of the rotation phase signal is adjusted. The output signal of the PGMM 8 is output to the phase comparator 9 as well as HS.
It is output to the sub-code gate generator 13 as a W signal. The phase comparator 9 compares the phase of the signal from the PGMM 8 with the reference signal from the reference signal generator 10, and outputs the error resulting from the comparison as an error voltage to the mixing circuit 16.

AF from the frequency discriminator 5 in the mixing circuit 16
The C system error voltage and the APC system error voltage from the phase comparator 9 are mixed and output to the drive circuit 11. The drive circuit 11 controls the rotation of the rotary head drum 1 so as to correct the error component by the error voltage.

The output signal of the PGMM 8 is input to the subcode gate generator 13 as the HSW signal 12, and the subcode gate generator 13 outputs the subcode gate pulse (SC) indicating the subcode recording position on the magnetic tape 2.
G) is created.

On the other hand, the FG signal output from the FG amplifier 4 is also input to the period measurement correction factor calculator 14,
During special reproduction, the period of the FG signal is measured to calculate the PGMM delay time according to the number of rotations of the rotary head drum 1 at each time, and the calculated PGMM delay time is input to the PGMM 8. Furthermore, the correction rate of the relative position and relative width of the SCG signal with respect to the FG signal is calculated,
Input to the subcode gate generator 13.

As described above, in the present embodiment, the rotation speed of the drum motor is changed in order to correct the relative speed change between the magnetic head and the magnetic tape during special reproduction in which the tape is sent at a tape speed different from that during recording. A cycle measurement correction rate calculator 14 is provided, and the rate of change of the rotation speed of the drum motor during special reproduction with respect to the rotation speed of the drum motor during recording (relative speed correction rate) is calculated by measuring the cycle of the FG signal. The amount of delay in the PGMM 8 is changed in proportion to the calculated value.

In the present embodiment, the change rate of the rotation speed of the drum motor (relative speed correction rate) is calculated using the FG signal. However, the cycle of the rotation phase signal (PG signal) output from the PG amplifier 7 is changed. The same effect can be obtained by using the method of calculating by measuring

[0047]

As described above, according to the present invention, even when the rotary head drum does not reach the target rotational speed yet, the magnetic head scans the adjacent video signal recording area even when the magnetic head scans the subcode area. It is possible to obtain an excellent effect of preventing erroneous scanning and overlapping of the SCG signal in the video signal recording area during recording.

[Brief description of drawings]

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

FIG. 2 is a characteristic diagram of the rotational speed and the correction rate of the rotary head drum in the FF mode in the same embodiment.

FIG. 3 is a characteristic diagram of the rotational speed and the correction rate of the rotary head drum in the REW mode in the same embodiment.

FIG. 4 is a block diagram showing a configuration of a second embodiment of a magnetic recording / reproducing apparatus of the present invention.

FIG. 5 is a block diagram showing the configuration of a conventional magnetic recording / reproducing apparatus.

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

FIG. 7 is a timing chart of each signal in the conventional magnetic recording / reproducing apparatus.

FIG. 8 is a schematic diagram showing a track pattern and a head locus during special reproduction in a helical scan VTR.

FIG. 9 shows a P at 1 × speed in a conventional magnetic recording / reproducing apparatus.
Timing chart of G signal, PGMM delay signal, and HSW signal

FIG. 10 is a timing chart of a PG signal, a PGMM delay signal, and an HSW signal during a forward fast search in a conventional magnetic recording / reproducing apparatus.

FIG. 11 is a timing chart of a PG signal, a PGMM delay signal, and an HSW signal at the time of reverse high speed search in the conventional magnetic recording / reproducing apparatus.

FIG. 12 is a timing chart of a DV track pattern, HSW signal, and SCG signal at 1 × speed in a conventional magnetic recording / reproducing apparatus.

FIG. 13 shows a DV track pattern, HSW signal, and SCG at the time of forward high speed search in the conventional magnetic recording / reproducing apparatus.
Signal timing chart

FIG. 14 is a DV track pattern, HSW signal, and SCG at the time of reverse high-speed search in the conventional magnetic recording / reproducing apparatus.
Signal timing chart

[Explanation of symbols]

1 rotating head drum 2 magnetic tape 3 frequency generator sensor 4 FG amplifier 5 frequency discriminator 6 Phase signal sensor 7 PG amplifier 8 PG Mono Multi 9 Phase comparator 11 Drive circuit 13 Sub-code gate generator 14 Period measurement correction factor calculator

Claims (4)

(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 a rotation speed signal, a frequency discriminator for extracting a modulation signal from the rotation speed signal and outputting the remaining signal as a first error signal, and a phase for detecting a rotation phase of the rotary head drum. Detecting means, phase signal amplifying means for amplifying the rotational phase signal from the phase detecting means, PG mono-multi for adjusting the delay time of the phase signal output from the phase signal amplifying means, and output of the PG mono-multi A phase comparator for comparing the signal and the reference signal and outputting the comparison result as a second error signal; and a first error signal from the frequency discriminator The mixing means for mixing the second error signal from the phase comparator, the driving means for controlling the rotation of the rotary head drum based on the error signal mixed by the mixing means, and the PG mono-multi With a subcode gate creation means that creates a subcode gate signal based on the output signal of
During special playback of sending a tape, the drum motor
Rotational speed of drum motor during special playback against rotational speed
Change rate of the output signal from the PG mono-multi
It is calculated by measuring, and the delay amount of the PG monomulti and the PG mono signal of the subcode gate signal in the subcode gate creating means are proportional to the calculated value.
Position relative to the output signal and the subcode gate signal.
A magnetic recording / reproducing apparatus, comprising: a period measurement correction factor calculating means for controlling so as to change the pulse width of the signal . 2. The rate of change of the rotational speed of the rotary head drum during special reproduction with respect to the rotational speed of the rotary head drum during recording and normal reproduction is calculated by measuring the cycle of the PG mono-multi output signal, A magnetic recording / reproducing apparatus characterized in that a relative position and a pulse width of a signal indicating a position of a first recording area on a magnetic tape from a head switching signal are changed in proportion to a calculated value. 3. 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 the rotating speed detecting means. A speed signal amplifying means for amplifying a rotation speed signal, a frequency discriminator for extracting a modulation signal from the rotation speed signal and outputting the remaining signal as a first error signal, and a phase for detecting a rotation phase of the rotary head drum. Detecting means, phase signal amplifying means for amplifying the rotational phase signal from the phase detecting means, PG mono-multi for adjusting the delay time of the phase signal output from the phase signal amplifying means, and output of the PG mono-multi A phase comparator for comparing the signal and the reference signal and outputting the comparison result as a second error signal; and a first error signal from the frequency discriminator The mixing means for mixing the second error signal from the phase comparator, the driving means for controlling the rotation of the rotary head drum based on the error signal mixed by the mixing means, and the PG mono-multi With a subcode gate creation means that creates a subcode gate signal based on the output signal of
During special playback of sending a tape, the drum motor
Rotational speed of drum motor during special playback against rotational speed
The rate of change of the period of the output signal from the speed signal amplifying means
Is calculated by measuring, and the delay amount of the PG mono-multi is proportional to the calculated value, and the PG monomer of the sub-code gate signal in the sub-code gate creating means .
Position relative to multi output signal and sub code gate
A magnetic recording / reproducing apparatus comprising: a period measurement correction factor calculating means for controlling so as to change a pulse width of a signal . 4. The rate of change of the rotational speed of the rotary head drum during special reproduction with respect to the rotational speed of the rotary head drum during recording and normal reproduction is calculated by measuring the cycle of the rotational speed signal, and the calculated value is used as the calculated value. A magnetic recording / reproducing apparatus characterized in that a relative position and a pulse width of a signal indicating a position of a first recording area on a magnetic tape from a head switching signal are proportionally changed.