JPS58175160A - Magnetic picture recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the precision of detection of a tape residual quantity or the like, by providing a rotation phase controlling means, a speed information detecting means, a frequency dividing means, and a phase comparing means. CONSTITUTION:At a recording time, a recording control signal generating circuit 4 is connected to a control head 6 through a switch SW 5. A signal FG obtained by a frequency generator 7 which detects rotation information of a capstan motor 2 has the waveform shaped in an FGAMP 8 and is inputted to an FG frequency dividing circuit 21 with a set terminal, and the frequency-divided output signal is inputted to a capstan phase comparing circuit 12 through a tracking shifter circuit 11. At a reproducing time, the control signal recorded on a magnetic tape 3 is detected by the control head 6 and has the waveform shaped by the SW 5 and a reproducing control amplifier 17, and the output is inputted to the set terminal of the FG frequency dividing circuit 21 through a SW 23.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording/playback device, which maintains the playback tape speed constant even when playing back an unrecorded portion of a magnetic tape in which a playback control signal is not recorded. The purpose is to accurately measure quantities, etc.

FIG. 1 shows a conventional example of a capstan motor control circuit in a magnetic recording/reproducing device. In FIG. 1, a magnetic tape 3 is transported by a cabstan motor 2 directly connected to a capstan shaft 1.

During recording, a recording control signal 4 is sent to the control head 6 via a switch (hereinafter referred to as sw) 5 (SW5 is conductive to the R side). In addition, a signal obtained by the frequency generator 7 that detects the rotation information of the capstan motor 2 (hereinafter referred to as the FG multiplied signal) is transmitted to the FG amplifier (hereinafter referred to as the FG multiplied signal).
GAMP) 8 to shape the waveform and input it to the FG frequency divider circuit 9. The output signal frequency-divided in this way is 5W1o
(SWlo is conductive to R side) and tracking shifter circuit 1
1 to the capstan phase comparator circuit 12. On the other hand, the recording capstan phase reference signal generation circuit 13
The signal from SWl 4 (SWl 4 conducts to the R side)
The signal is input to the capstan phase comparator circuit 12 through the capstan phase comparator circuit 12.

The phase comparison circuit 12 compares the phase of this input signal with the signal from the tracking thick circuit 11, and the obtained phase comparison error signal is sent to the capstan motor drive circuit 15.
is input.

Also, the output of FGAMP8 is the capstan speed control circuit, -
The capstan motor 2 is controlled at a constant speed by the output of the capstan motor drive circuit 16 via the line 16.

During playback, the control signal recorded on the magnetic tape 3 is detected by the control head 6 and SW5 (S
W5 conducts to the P side), the waveform is shaped and shaped by the playback control amplifier 17, and the output after shaping is 5W10 (S
Wlo is connected to the P side) and is input to the capstan phase comparator circuit 12 through the tracking shifter circuit 11. On the other hand, the reproduction capstan phase □ reference signal generation circuit 18
The signal is input to the capstan phase comparator circuit 12 through 5W14 (SWl 4 is conductive to the P side), where it is phase-compared with the signal of the tracking thick circuit 11, and the phase comparison error signal is input to the capstan motor drive circuit 15. Ru. Further, the output of the FGAMP 8 is input to the capstan speed control circuit 16 and sent out from the speed control circuit 16. The speed control error signal is sent to the capstan motor drive circuit 15.
is input. The capstan motor 2 is then driven by the output of the drive circuit 16. At this time, since the control signal for the magnetic tape 3 is synchronized with the reproduction capstan phase reference signal, the control signal for the magnetic tape 3 is synchronized with the reproduction capstan phase reference signal.
is transported, and the rotating video head and the playback control signal are tracked, so that the video and audio are normally played back.

However, when a portion of the tape 3 without a reproduction control signal, that is, an unrecorded image portion, is reproduced, the output of the phase comparator circuit 12 is not determined because there is no reproduction control signal to be controlled, and the capstan motor 2 The rotational speed is within the hold range (10% of catch) of the capstan phase control circuit 16, and the tape playback speed differs from time to time. Therefore, if the tape playback speed differs, for example, the accuracy of detecting the remaining amount of tape will deteriorate, and in the worst case, the tape will be transported at a tape speed corresponding to the limit value of the hold range of the capstan phase control circuit, so the accuracy of detecting the remaining amount of tape will deteriorate. The disadvantage is that it becomes very bad.

``The present invention eliminates these drawbacks.

An embodiment of the present invention will be described below with reference to FIG.

FIG. 2 is a block diagram of a magnetic recording and reproducing apparatus which is an embodiment of the present invention. In the figure, 1 is a capstan shaft directly connected to the capstan motor 2, 3 is a magnetic tape that is transferred by rotation of the capstan shaft 1, and 4 is a recording control signal oscillator, which is connected to the control head 6 via SW5.
sends a control signal to. 7 is a frequency generator that detects the rotation information of the capstan motor, 8 is a FGAMP that shapes the FG multiplied signal waveform, 21 is an FCr frequency divider circuit with a set terminal, 11 is a tracking shifter circuit, and 12 is a capstan phase comparison circuit. . 22 is a recording capstan phase reference signal generation circuit connected to the capstan phase comparison circuit 12 via SWl 4, 18 is a reproduction capstan/phase reference signal generation circuit, 16 is a capstan speed control circuit, and 16 is a capstan The motor drive circuit 17 is a reproduction control amplifier.

Next, the operation of this device will be explained.

First, during recording, the recording control signal generation circuit 4 is set to S.
It is connected to the control head 6 via Wa (SWs are conductive to the R side). In addition, a signal obtained by the frequency generator 7 that detects rotation information of the capstor/motor 2 (hereinafter referred to as the FG multiplied signal) is waveform-shaped by FGAMPa, inputted to the set terminal FG frequency dividing circuit 21, and frequency-divided. The output signal is passed through the tracking shifter circuit 11 to the capstor/
It is input to the phase comparator circuit 12. On the other hand, the signal from the recording capstan phase reference signal generation circuit 22 is SWl 4 (S
Wl4 is connected to the R side) and is input to the capstan/phase comparator circuit 12, where the phase is compared with the signal from the tracking shifter circuit 11, and the phase comparison error signal is input to the capstan motor 1 drive circuit 16. Also, F
(The output of AMP8 is input to the capstan speed control circuit 16, and the speed control error signal output from the speed control circuit 16 is input to the capstan motor drive circuit 15, and the output drives the capstan motor 2. During playback, the control head 6 detects the file control signal recorded on the magnetic tape 3, and the waveform is shaped by the SWs (SWs is connected to the P side) and the playback control amplifier 17, and its output is 5W23 (S
V40 is connected to the P side) and is input to the set terminal of the FGG circuit 21.

The FG multiplied signal from FGAMPa is input to the set terminal material FCr frequency dividing circuit 21, and if there is a reproduction control signal, a signal synchronized with the reproduction control signal becomes the output of the set terminal material FG frequency dividing circuit 21. Further, when there is no reproduction control signal, a signal obtained by dividing the frequency of the FG times signal becomes the output of the set terminal type FG frequency dividing circuit 21. This output passes through a tracking shifter circuit 11 and is input to a capstan phase comparison circuit 12. On the other hand, the signal from the reproduction capstale phase reference signal generation circuit 18 is 5W14.
(SW14 is conductive to the P side) and is input to the capstan phase comparator circuit 12, and the tracking thick circuit 1
The phase is compared with the signal from 1.

Next, the phase comparison error signal output from the phase comparison circuit 12 is input to the capstan motor drive circuit 15.

The output of FGAMPa is still capstan speed control circuit 1.
6, the speed control error signal is input to a capstan motor drive circuit 16, and its output drives the capstan motor 2. However, since the control signal for the magnetic tape 3 is synchronized with the playback capstan phase reference signal, the magnetic tape 3 is transported at a speed that matches the recording tape speed, and the rotating video head (not shown) and the playback control signal are not tracking. video and audio are played back correctly.

Next, the case where there is no playback control signal, that is, the unrecorded portion of the magnetic tape 3 is played back will be explained. - In general, the role of the capstan motor 2 during recording in a magnetic recording/playback device is to run the tape at a constant speed to maintain an accurate tape speed, and there is no need for tracking.
The signal frequency to be divided by G may be any number. Therefore, any number of capstan phase reference signals may be used during recording, but the following relationship must hold. That is, if the tape speed during recording is [machi sea], the tape thickness δ (zm), and the number of revolutions to the east of the capstan N (r, p, s), then N == S/h (D + δ). If the relationship is established and the number of teeth of the frequency generator 7 is Z, the frequency f (H2) of the frequency generator 7 becomes f=Z,N, and the frequency division ratio of the FGG frequency generator 9 is set to n. For example, the capstan phase reference frequency fψRec (Hz) during recording is f
It becomes ψRec-f/n. On the other hand, the reproduction capstan phase reference frequency ftpp
, m is 29.97 (Hz') in the case of the NTSC system.
, PAL, SECAM system: 26.00 (H2
) Te. Therefore, the capstan phase reference frequency fψR&c during recording is the capstan phase reference frequency fψR&c during reproduction.
Select ψp to be lower than B, and set the frequency several times.
The number of teeth Z (number of teeth) and the FG frequency division colorimetric record capstan phase reference frequency fψR6C (Hz) are determined. By doing as described above, even in the part where there is no reproduction control signal during reproduction, the signal obtained by dividing the FG multiplied signal by FG is input to the phase comparator circuit 12, so that the capstan motor 2 has a phase adjustment control force. ;The magnetic tape 3 is fed at a constant speed. The tape speed at that time is determined by the recording capstan phase reference frequency f (p*ec) and the reproduction capstan phase reference signal frequency fψ, so the recording capstan phase is It is desirable that the reference frequency fψRho is set lower than the reproduction caster/phase reference frequency fψRho by about 1°o%.

As described above, according to the present invention, even in the non-signal portion where no control signal is recorded, the tape speed is approximately 1.0 times higher than the normal tape speed. Although it is Q% faster, it is constant and the tape speed does not constantly change in the upper 10% range as in conventional devices, so it greatly improves the accuracy of, for example, detecting the remaining amount of tape. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a capstan motor control circuit section of a conventional magnetic recording/reproducing apparatus, and FIG. 2 is a block diagram of a capstan motor control circuit section of a magnetic recording/reproducing apparatus according to an embodiment of the present invention. 1... Capstan shaft, 2... Capstan mole signal oscillator, 5, 10, 14, 23...
...Switch, 6...Control head, 7
...Frequency generator, 8...FGAMP
, 9... Fσ frequency dividing circuit, 11... Tracking shifter circuit, 12... Capstan phase comparison circuit, 13, 22... Recording capstan phase Reference signal generation circuit, 16...Capstan motor, drive circuit, 16...Capstan speed control circuit, 17...Reproduction control amplifier,
18...Reproduction gear 122 phase reference signal generation circuit, 21...Set terminal FG frequency dividing circuit.

Claims (2)

[Claims] (1) A head motor that rotates a rotary magnetic head;
A capstan motor that rotates a capstan for transporting a magnetic tape, a rotational phase control means that controls a rotational phase of the capstan motor, a speed information detection means that detects speed information of the capstan motor, and the speed information a frequency dividing means for frequency dividing the output of the detection means, a recording capstan reference signal generator for generating a recording capstan 7 reference signal, an output of the recording capstan reference signal generator, and an output of the frequency dividing means. a phase comparison means for comparing phases and controlling the rotational phase control means by the phase comparison error signal; a control head for recording or reproducing a control signal on a magnetic tape; and a reproduction capstan reference signal for generating a reproduction capstan reference signal. The frequency dividing means for frequency dividing the output of the speed information detecting means during reproduction is forcibly set by a reproduction control signal from the control head, and the output of the frequency dividing means and the reproduction cap are forcibly set. A magnetic recording and reproducing apparatus characterized in that the output of the stand reference signal generator is compared with the output of the stun reference signal generator by the phase comparison means, and the rotational phase control means is operated by the output of the phase comparison means. (2) The magnetic recording and reproducing apparatus according to claim 1, wherein the frequency of the reproduction capstan reference signal is higher than the frequency of the recording capstan reference signal.