JPH0644811B2 - Capstan control circuit for magnetic recording / reproducing apparatus - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capstan control circuit for a magnetic recording / reproducing apparatus, and more particularly to controlling the capstan during still reproduction and recording in a magnetic recording / reproducing apparatus having a still reproducing function. Regarding the circuit.

2. Description of the Related Art In recent years, a magnetic recording / reproducing apparatus has been developed in which a rotary audio head is provided on the same rotary drum as a video head, and an audio signal is recorded and reproduced by the rotary audio head. The audio heads A (1) and A (2) of this type have an azimuth angle of ± 30 °, and as shown in FIG. 3, double gear type video heads SP (1) and SP (2) (standard play (2 (Time)) is offset by θ °. In addition, E
P (1) and EP (2) are video heads of extended play (6 hours). The apparatus having the above-mentioned configuration employs a so-called deep layer recording method in which an audio signal is recorded first and then a video signal is recorded at the time of recording.

In this case, since the audio track shown in FIG. 4 is overlap-recorded at the switching of each channel, the signal reproduced by the audio heads A (1) and A (2) during reproduction (FIG. 2 (S)). , (T)) with the audio switching pulse e ((O) in the figure) delayed by the time tθ (corresponding to θ °) with respect to the drum switching pulse d ((D) in the figure). is there. The figure (U) shows the audio signal extracted by switching. This switching is necessary only during normal reproduction, and is unnecessary during recording and still.

FIG. 5 shows a block system diagram of an example of a conventional circuit. The video signal coming into the terminal 1 is separated from the vertical sync signal by the vertical sync signal separation circuit 2, reset by the vertical sync signal at 30 Hz at the time of recording, and 30 Hz by the oscillation circuit 3 which runs at 30 Hz during the reproduction. Signal for each X-value correction mono-multi 4, 5 depending on the 2-hour mode or 6-hour mode
The pulse width is adjusted by, and the waveform shaping circuit 6 makes a control pulse, which is supplied to the control head 8 via the recording amplifier 7 and recorded on the magnetic tape.

Here, in consideration of tape compatibility, when the rotary head 50 for scanning in the direction of the arrow B is located at the exit (end portion) of the video track 56 as shown in FIG. 6, the control pulse at that time is recorded. It is well known that the distance on the magnetic tape 57 between the position of the fixed control head 8 and the position of the rotating head 50 at that time (this control head position is referred to as "X value") is defined. (For example, Japanese Patent Application No. 55-
69870, "Magnetic Recording and Reproducing Apparatus", page 5, pages 8 to 1
There is a disclosure regarding "X value" in line 6 and FIG.

On the other hand, the output signal of the oscillation circuit 3 is converted into a sample pulse by the sample pulse generation circuit 9 and supplied to the phase comparison circuit 10. Drum PG pulse a from the drum motor 11
(FIG. 2 (A)) is a signal b (FIG. 2 (B)) and a signal c (FIG. 2 (C)) in the first and second channel mono-multis 12 and 13, and the flip-flop 14 serves as a drum. A switching pulse d ((D) in the figure) is formed into a trapezoidal wave signal by the trapezoidal wave generation circuit 15, and is supplied to the phase comparison circuit 10.

In the phase comparison circuit 10, the trapezoidal wave signal and the sample pulse are compared in phase to extract a phase comparison error signal, which is supplied to the drum motor 11 via the low-pass filter (LPF) 16 to drive and control the drum motor 11.

Here, during recording and normal reproduction, the flip-flop 14
The drum switching pulse d from is also supplied to the device operation control microcomputer 17 (mechanical control circuit),
For example, when the rotation of the rotary drum is stopped, an operation such as stopping the mechanism is performed, and it is supplied to the video circuit 29 to perform color rotation and FM switching. Further, at the time of recording, the drum switching pulse d is used to set a timing for performing a video blanking switch when recording is resumed after the recording stop is released (joint editing). On the other hand, during the normal reproduction, as described above, the drum switching pulse d is delayed by the delay circuit 18 by the time t _θ to become the audio switching pulse e (FIG. 2 (O)), and is supplied to the switching circuit 19 for reproduction. The audio signal is switched for each channel.

By the way, the position where the magnetic tape stops during still reproduction or intermittent feed slow motion reproduction must be a position where there is no noise on the reproduced image. The still reproduction video signal input to the terminal 20 is amplified by the amplifier 21 into a signal f (FIG. 2 (P)), the FM envelope is detected by the FM envelope detection circuit 22, and the level drop point detection signal is detected. g ((Q) in the figure) and is supplied to the mechanical control circuit 17. On the other hand, the drum switching pulse d has its pulse width adjusted by the still stop position correcting mono-multis 23 and 24, and is supplied to the mechanical control circuit 17 as a drum phase signal by the waveform shaping circuit 25.

In the mechanical control circuit 17, the relative phase relationship between the drum switching pulse d and the dropout detection signal g becomes a constant value T ₃ (for example, 3 msec), that is, the phase of the output of the waveform shaping circuit 25 and the dropout detection signal g has a constant value. The control signals required for this are taken out as follows. This control signal is used as a stop signal by the capstan motor stop circuit 26, and the capstan motor 27 is stopped at a predetermined position to stop the magnetic tape. In this case, the value of T ₃ varies depending on the device, so the value is adjusted by the still stop position correcting monomultis 23 and 24.

Problems to be Solved by the Invention The above-mentioned conventional circuit requires two types of mono-multis 4 and 5 for X-value correction and mono-multis 23 and 24 for still stop position correction. There were problems such as not getting.

It is an object of the present invention to provide a capstan control circuit of a magnetic recording / reproducing apparatus, which can be used as both an X value setting mono-multi and a still stop position setting mono-multi so that the circuit can be configured easily and inexpensively.

Means for Solving the Problems The present invention has a magnetic control device having a capstan stop control circuit for stopping and controlling the capstan so as to stop the magnetic tape at a position where there is no noise on the screen during still reproduction or intermittent slow motion reproduction. In the capstan control circuit of the recording / reproducing apparatus, the first monomulti connected to the X value setting element and the still stop position setting element in the 2-hour mode, and the X value setting element and the still stop in the 6-hour mode A second mono-multi connected to each of the position setting elements, and the first and second mono-multis according to the time modes.
And a selector switch for switching and outputting each output of the mono-multi to the capstan stop control circuit.

The first mono-multi which also functions as the X value correction or the still stop position correction in the 2-hour mode can independently set the time constants suitable for the respective corrections.
The second mono-multi, which also serves as value correction or still stop position correction, can independently set the time constants suitable for each correction.
Then, the output of the first and second mono-multis corresponding to each time mode (two-hour mode or six-hour mode) (phase correction according to X value correction or still stop position correction) is corrected using the changeover switch. Output) can be switched and supplied to the capstan stop control circuit. Therefore, the X value correction at the time of recording in each time mode or the still stop position correction at the time of reproduction can be set finely and accurately.

Further, the first and second mono-multis serve both as the X-value setting mono-multi and the still-stop-position setting mono-multi, so that the circuit can be configured more simply than the conventional circuit.

Embodiment FIG. 1 shows a block system diagram of an embodiment of the circuit of the present invention. In the figure, the same components as those in FIG. 5 are designated by the same reference numerals and the description thereof will be omitted. In the figure, 4 ', 5'denotes a mono-multi for both X value correction and still stop position correction, which uses volume VR ₁ and VR ₂ for still stop position correction, and uses volume VR ₃ and VR ₄ for X value correction. And
Further, the changeover switch 6a is configured to switch between the 2-hour mode and the 6-hour mode, the mono-multi 4'corresponds to the first mono-multi in the claims and the mono-multi 5'in the claims. Corresponding to the second mono-multi, and the changeover switch 6a corresponds to the changeover switch in the claims,
It forms an essential part of the circuit of the present invention.

That is, 2-hour mode multivibrator 4 which also serves as the X value correcting or still stop position correction in (2H) 'is an element VR ₃ and still stop position setting device VR ₁ for X values set by using the changeover switch 4'a By switching, the time constant adapted to each correction can be changed independently. Switching switch 4'a connection contacts 4'a1 connected to one end of the X value setting device VR _3, the movable contact 4'a2 is connected to the multivibrator 4 ', to one end of the still stop position setting device VR ₁ The contact 4'a3 is provided.

Further, the mono-multi 5'which also serves as the X value correction or the still stop position correction in the 6-hour mode (6H) uses the changeover switch 5'a to operate the X value setting element VR ₄ and the still stop position setting element VR ₂ . By switching, the time constant adapted to each correction can be changed independently. The switching switch 5'a is connected to a contact 5'a1 connected to one end of the X value setting element VR ₄ , a movable contact 5'a2 connected to the monomulti 5 ', and one end of a still stop position setting element VR _2. The contact 5'a3 is provided.

The outputs of the monomultis 4'and 5'are selected by the switching switch 6a according to the selection of the 2-hour mode or the 6-hour mode, and then output to the waveform shaping circuit 6. The switching switch 6a is a contact 6a connected to the output side of the monomulti 4 '.
1. Movable contact 6a connected to input side of waveform shaping circuit 6
2. The contact point 6a3 is connected to the output side of the monomulti 5 '.

Here, FIG. 2 (E) is a trapezoidal wave signal h output from the trapezoidal wave generating circuit 15, FIG. 2 (F) is a video signal i coming into the terminal 1 during recording, and FIG. 2 (G) is a signal i. The vertical synchronizing signal j output from the vertical synchronizing signal separation circuit 2 input by the same, the figure (H) is an output signal k from the oscillating circuit 3 during recording / reproducing, and the figure (I) is an X value setting for recording / reproducing. output signal 1 of the multivibrator 4 'whose pulse width is adjusted according to the change of the time constant by the variable element VR _3, FIG. (J) the control pulses m is the output of the waveform shaping circuit 6 a signal 1 is inputted , (K) is a sampling pulse n which is the output of the sampling pulse generation circuit 9, and (L) is a phase comparison circuit 10.
A phase comparison error signal o obtained by phase-comparing the trapezoidal wave signal h and the sample pulse n in FIG. 6 (M) shows a still stop position setting element VR ₁ during still reproduction or intermittent feed slow motion reproduction. The output signal p of the monomulti 4'whose pulse width is adjusted according to the change of the time constant by variability, the figure (N) shows the signal q which is the output of the waveform shaping circuit 6 to which the signal p is inputted, and the figure (R). ) Is the capstan motor stop circuit 2
6 shows respective waveforms of the output signal 6 (voltage supplied to the capstan motor 27) r.

Now, the X value is set at the time of recording or reproducing in the 2-hour mode as follows.

First, it switches the 'switching switch 4a to connect to the' X-value setting device VR ₃ multivibrator 4, synchronize already have been set X value with the rise of the output signal k of 30Hz supplied from the oscillation circuit 3 The output signal 1 having the pulse width of the time constant corresponding to is output from the monomulti 4 '. Thus, the signal 1 is supplied to the control head 8 via the waveform shaping circuit 6 and the recording amplifier 7 via the switching switch 6a switched to the side of the monomulti 4 ', and recorded on the magnetic tape as the control pulse m. However, a good reproduced image cannot be obtained even if this magnetic tape is reproduced by another device whose normal X value is adjusted.

Therefore, next, a reproduction signal f which reproduces a standard tape (recorded with a normal X value) is supplied to the terminal 20, and the reproduction FM signal of the reproduction signal f is set to the above X level. The value of the value setting element VR ₃ is adjusted. In this way, the pulse width of the output signal 1 of the monomulti 4'changes accordingly, and as a result, the control pulse m adapted to the normal X value can be finally obtained.

Therefore, the video signal i can be recorded with a normal X value, and
Even if the image is reproduced by another device adjusted to the normal X value, a compatible reproduced image can be obtained.

The above is the setting of the X value at the time of recording or reproduction in the 2 hour mode. Similarly, by adjusting the value of the X value setting element VR ₄ of the monomulti 5 ′, the 6 hour mode is set. Of course, the X value can be set during recording or reproduction.

The still stop position is set in the two-hour mode during self-recording reproduction and still reproduction or intermittent feed slow motion reproduction.

First, it switches the 'switching switch 4a to connect to' the element VR ₁ for still stop position setting multivibrator 4,
An output signal p having a pulse width of a time constant corresponding to the still stop position that has been set in synchronization with the rising edge of the output signal k supplied from the oscillation circuit 3 is output from the monomulti 4 '. In this way, this signal p is supplied to the mechanical control circuit 17 via the waveform shaping circuit 6 and the switch 28 via the switching switch 6a switched to the side of the monomulti 4 ', but this tends to cause noise on the reproduced screen to stand out. An inconvenient reproduction state appears in the center of the screen.

As described above, the position where the magnetic tape should be stopped during still reproduction or intermittent slow motion reproduction must be a position where there is no noise on the reproduction screen. The value of the still stop position setting element VR ₁ is adjusted so that the noise on the reproduction screen is minimized on the monitor. That is, until the phase difference T _4-1 (shown in FIG. 2 (Q)) between the rising edge of the output signal q of the waveform shaping circuit 6 and the rising edge of the output signal g of the FM envelope detection circuit 22 becomes 0 (drum switching). The voltage r is continuously applied to the capstan motor 27 until the relative phase relationship between the pulse d and the output signal g reaches a constant value T ₃ . As a result, when the phase difference T _4-3 between the signal q and the signal g becomes 0, the voltage r is no longer applied to the capstan motor 27, so that the rotation of the capstan motor 27 is stopped, whereby the magnetic tape is stopped. It is possible to control the stop position of.

Accordingly, the still stop position setting element V of the monomulti 4 '
By adjusting R ₁ , the phase differences T _4-1 , T _4-2 , T _4-3 between the signal q and the signal g can be arbitrarily adjusted, and thus the phase difference between the signal d and the signal g can be adjusted. It is easily adjusted to a constant value T ₃ . When the value of the optimum stop position T ₃ differs depending on the device, the still stop position setting element VR ₁ may be readjusted to the optimum value.

The above is the still stop position setting during the 2-hour mode still reproduction or the intermittent feed slow motion reproduction. Similarly, the value of the still stop position setting element VR ₂ of the monomulti 5 ′ is adjusted. Therefore, it is needless to say that the still stop position can be set during the 6-hour mode still reproduction or the intermittent feed slow motion reproduction.

At the time of recording, the output signal of 30 Hz of the oscillating circuit 3 is taken out with the pulse widths corresponding to the X value corrected by the volume VR ₃ and VR ₄ of the monomulti 4'and 5 ', the waveform shaping circuit 6 and the recording amplifier 7. It is supplied to the control head 8 via and is recorded on the magnetic tape as a control pulse. At this time, the drum switching pulse d from the flip-flop 14 is supplied to the mechanical control circuit 17 via the switch 28, and is used as the rotation stop detection signal of the rotary drum and the timing signal for connection editing as described above.

During normal reproduction, the audio switching pulse e from the delay circuit 18 is supplied to the switching circuit 19 via the switch 28 and used as the reproduction audio signal switching signal as described above, while being supplied to the mechanical control circuit 17 to stop the rotation drum. It is used as a detection signal.

By the way, in the present embodiment, it is assumed that the output signal k of the oscillation circuit 3 and the drum switching pulse d are phase-locked during still reproduction. At the time of still reproduction, the output signal k of the oscillation circuit 3 (substantially the flip-flop 14 shown in FIG.
(The same as the output signal of) is taken out with the pulse widths corresponding to the still stop positions corrected by the volumes VR ₁ and VR ₂ of the monomultis 4'and 5 ', and the waveform shaping circuit 6 and the switch 28.
Is supplied to the mechanical control circuit 28 via. The signal extracted through the waveform shaping circuit 6 and the switch 28 is substantially the same as the output signal of the waveform shaping circuit 25 shown in FIG.

As described above, according to the present invention, since the monomultis 4'and 5'for both X value correction and still stop position correction are provided, the circuit can be configured more simply than the conventional circuit.

If the output signal k of the oscillation circuit 3 and the drum switching pulse d are not phase-shift locked during still reproduction, the output signal k of the oscillation circuit 3 is taken out of the flip-flop 14 during still reproduction. Drum switching pulse d
May be supplied to the mono-multi 4 ', 5'.

Further, at the time of still reproduction, if the control pulse reproduced from the control head 8 is supplied to the monomultis 4'and 5'to obtain the still stop position control signal, it is not necessary to provide the FM envelope detection circuit 22. The circuit can be simply constructed, and the number of input ports of the mechanical control circuit 17 can be further reduced.

Further, fixed resistors may be used instead of the volumes VR ₁ to VR ₄ as long as the X value and the still stop position need not be corrected.

Further, as shown in FIG. 1 (B), tracking is provided to correct tracking deviation during reproduction without providing still stop position correcting volumes VR ₁ and VR ₂ on the monomultis 4 ″ and 5 ″. The multi-multi 31 may be provided with still stop position correcting volumes VR ₁ ′ and VR ₂ ′. This switch connects the switch that switches between when the tracking shift correction is necessary and when it is not needed and the ST terminal of the switch 28, and supplies the output of the mono-multi 4 ″, 5 ″ to the mechanical control circuit 17 only during still reproduction. Or the output of the tracking mono-multi 31 to the mechanical control circuit 17 is switched.

EFFECTS OF THE INVENTION According to the circuit of the present invention, the first mono-multi which also serves as X value correction or still stop position correction in the 2-hour mode can independently set time constants suitable for the respective corrections.
The second mono-multi which also serves as the X value correction or the still stop position correction in the time mode can independently set the time constant suitable for each correction, and by using the changeover switch,
A capstan stop control circuit for outputting each output of the first and second monomultis corresponding to each time mode (two-hour mode or six-hour mode) (phase-corrected output corresponding to X value correction or still stop position correction) Since it is possible to switch and supply to each time mode, the X value correction at the time of recording or the still stop position correction at the time of reproduction can be set finely and accurately, respectively, whereby the tape position stop control of the capstan can be performed accurately. In particular, it is possible to eliminate an inconvenient reproduction state in which noise appears on the reproduction screen in the central portion of the screen where the noise tends to stand out, and the first and second mono-multis are the X-value setting mono-multi and still. Since it is also used as a stop position setting mono-multi, it has a feature that the circuit can be configured easily and inexpensively as compared with the conventional circuit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block system diagram of one embodiment and another embodiment of the circuit of the present invention, FIG. 2 is a signal waveform diagram of the circuit of the present invention and a conventional circuit, FIG. 3 and FIG. Is a diagram for explaining the position of the rotating audio head and its tracking pattern,
FIG. 5 is a block system diagram of an example of a conventional circuit, and FIG. 6 is a diagram for explaining the position of the control head. 1 ... Video signal input terminal, 2 ... Vertical sync signal separation circuit,
3 ... Oscillation circuit, 4 ', 5' ... Monomulti, 6 ... Waveform shaping circuit, 8 ... Control head, 11 ... Drum motor,
14 ... Flip flop, 17 ... Mechacon circuit, 18 ...
Delay circuit, 19 ... Switching circuit, 20 ... Reproduction video signal input terminal, 22 ... FM envelope detection circuit, 26
... capstan motor stop circuit, 27 ... capstan motor, 28 ... switch, 30 ... capstan servo circuit, 31 ... tracking multivibrator, VR _1, VR _2, V
R ₁ ′, VR ₂ ′ ... Still stop position correction volume, V
R _3, VR ₄ ... X value correction for Boriyumu.

Claims (1)

[Claims] 1. A capstan of a magnetic recording / reproducing apparatus having a capstan stop control circuit for stopping and controlling the capstan so as to stop the magnetic tape at a position where there is no noise on the screen during still reproduction or intermittent slow motion reproduction. In the control circuit, the first monomulti connected to the X value setting element and the still stop position setting element in the 2-hour mode, and the X value setting element and the still stop position setting element in the 6-hour mode, respectively. A second mono-multi connected thereto, and a changeover switch for switching and outputting each output of the first and second mono-multis to the capstan stop control circuit according to each time mode. Capstan control circuit of magnetic recording / reproducing device.