JPS62253279A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To realize special reproduction, such as slow reproduction, etc., with a magnetic recorder and reproducing device, by repeating an operation that stops a magnetic tape after running the magnetic tape for a prescribed length and storing reproduced signals in a memory when the tape is run, and then, outputting the stored reproduced signals when the tape is stopped. CONSTITUTION:A control circuit 10 controls the rotation and stoppage of a capstan by outputting control signals to a capstan driving circuit 9 synchronously to head switching pulses SWP. While a magnetic tape is run, RF signals are reproduced from inclined tracks. The RF signals become pilot signals after passing through an LPF 32 and the pilot signals are compared with a reference pilot signal, and thus, tracking error signals are implemented. The tracking error signals are outputted to the capstan driving circuit 9 and tracking-control a rotary head. Therefore, the writing and reading-out operations in and from a memory can be adjusted in accordance with the running and stopping timing of the magnetic tape even at the time of slow reproduction. Accordingly, excellent pictures can be obtained even when special reproduction is made.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing apparatus typified by an 8 mm video tape recorder.

[Summary of the invention]

In the present invention, the frame-by-frame advance operation is repeated, and when the magnetic tape is running, the signal reproduced by the rotary head is stored in memory, and when the magnetic tape is stopped, the stored signal is output and slowed down. Perform playback.

[Conventional technology]

In a conventional video tape recorder, as shown in FIG. 7, a video signal is recorded on an inclined track 11 on a magnetic tape, and an audio track 1 at one end is recorded.
2, and a CTL signal is recorded on the control track 13 at the other end. In order to perform slow playback by running such a magnetic tape at a predetermined speed slower than the standard running speed, a conventional video tape recorder is constructed as shown in FIG. 4, for example.

The CTL signal reproduced and extracted from the track 13 is input to the frequency dividing circuit 7, and the frequency dividing circuit 7 divides the CTL signal by n when running the magnetic tape at the standard speed l/n. Output to comparison circuit 8.

The comparison circuit 8 compares the switching pulse (SWP) for switching the rotary head with the frequency-divided signal, and outputs the difference to the capstan drive circuit 9 as a tracking error signal. Since the capstan drive circuit 9 controls the rotation of the capstan motor that drives the capstan, the magnetic tape runs at a set slow speed (1/n of the standard speed).

-6 The input video signal is supplied to the A/D conversion circuit 1, and after being converted from an analog signal to a digital signal,
The data is stored in a digital memory 6 such as a RAM controlled by a memory control circuit 3 consisting of a gate array or the like. The signal stored in the memory 6 is converted from a digital signal to an analog signal by the D/A conversion circuit 4, and after noise components are removed by the low-pass filter 5, it is supplied to one contact of the switch 2. The input signal is supplied as is to the other contact of switch 2.

A signal is output from one of the contacts under the control of a control circuit 10 comprising a microcomputer or the like.

For example, when a magnetic tape is running at 1/4 of the standard speed, a pair of rotating eights l<
As shown in Figure 5, A and B are
(In the figure, the solid line is the locus of rotary head A, and the broken line is the locus of rotary head B.)

The rotating heads A and B have mutually different azimuths (Chl, c
h2), only the signals from the portions where the azimuths match are reproduced. Therefore, the rotary heads A and B switched by the switching pulse are shown in FIG. 6(a).
Outputs an envelope RF multiplied signal as shown in . Fifth
A state in which the trajectory of the rotary head most closely matches the inclined track, as shown by trajectories a and i in the figure, appears once every eight fields. In this state, a good video signal with the least noise components can be obtained, so the control circuit 10
outputs a write pulse as shown in FIG. 6(b) to the memory control circuit 3 at that timing. The memory control circuit 3 stores the signals (a, c) input at this time in the memory 6, and the control circuit 10 switches the switch 2 to output the input signals as they are. Then, the control circuit 10 switches the switch 2 in other fields, and controls the signal (al) stored in the memory 6.
, CI). Therefore, as shown in FIG. 6(c), an image with less noise can be reproduced and output in slow motion.

[Problem that the invention seeks to solve]

In this way, conventional video tape recorders perform tracking control using the CTL signal not only during normal playback but also during slow playback.

However, in, for example, an 8 mm video tape recorder, pilot signals f□ to f4 of four different frequencies for tracking are sequentially recorded on each inclined track, and this pilot signal is used to perform tracking control during normal playback. .

In this way, a video tape recorder in which a CTL signal is not recorded cannot perform tracking control during slow playback using the CTL signal. Furthermore, unless a rotary head with a width wider than the inclined track is used, sufficient RF multiplied signals corresponding to the upper and lower portions of the screen cannot be obtained, resulting in a poor S/N ratio.

[Means for Solving the Problems] The present invention reproduces a tracking pilot signal recorded on an inclined track on a magnetic tape, compares it with a reference pilot signal to generate a tracking error signal, and generates a tracking error signal. In a magnetic recording/reproducing device that controls tracking of a rotating head in response to the rotational head and records/reproduces information on an inclined track using the rotating head, when the magnetic tape is running repeatedly by repeatedly running the magnetic tape for a predetermined length and then stopping. The signals reproduced by the rotary head are stored in a memory, and when the magnetic tape is stopped, the signals stored in the memory are output.

[Effect]

The operation of running the magnetic tape for a predetermined length and then stopping is repeated. When the magnetic tape is running, the running state is controlled in response to a 1-racking error signal generated from the reference pilot signal and the reproduction pilot signal. The playback signal while the magnetic tape is running is stored in memory,
Output when the magnetic tape is stopped.

〔Example〕

FIG. 1 is a block diagram of a magnetic recording/reproducing apparatus of the present invention, and parts corresponding to those in FIG. 4 are given the same reference numerals. In FIG. 1, 31 is an oscillation circuit, and the control circuit 10 controls the oscillation circuit 31 when the magnetic tape is run at a normal standard speed, and controls the half period (one field) of the head switching pulse for switching the rotating head.
For each section of , that is, for each inclined track corresponding to a winding angle of 180 degrees, the pilot (=sign f, to f4 are sequentially output in the reverse sequence (in the order of f4.f, , f8° fl) 32 is a low pass filter (LP
F), which separates and extracts the regenerated pilot signal from the regenerated RF signal.

For example, when a magnetic tape is run at 1/2 the standard speed for slow playback, the control circuit 10 operates the capstan drive circuit 9 in synchronization with the human-powered head switching pulse (FIG. 2(a)). control signal (Fig. 2 (C))
Depending on the performance of the capstan, for example (2
The operation of rotating the capstan for a period of +1/3) field and stopping the capstan for a period of (1+2/3) field is repeated. When the capstan is rotated and the magnetic tape is running, the RF multiplied signal is reproduced from the inclined track by the one-rotation head, and from this RF multiplied signal, a reproduced pilot signal is separated and extracted by the low-pass filter 32 and inputted to the comparator circuit 8. be done. At this time, the oscillation circuit 3
1 is controlled by a control circuit 10 and outputs a reference pilot signal to the comparison circuit 8 in synchronization with the head switching pulse. The comparison circuit 8 compares the reference pilot signal with the reproduced pilot signals (
A tracking error signal is generated from the crosstalk component) and output to the capstan drive circuit 9. As a result, the magnetic tape is run at the same speed as during normal recording and reproduction.

Therefore, a frame-by-frame forwarding operation is performed, which is completed once every four fields.

When the trace locus of the rotary head in this case is illustrated by the track pattern analysis method, it becomes as shown in FIG. 3(a), and the RF multiplied signal envelope reproduced at that time is as shown in FIG. 3(b). As is clear from the figure, the level of the RF multiplied signal envelope reaches its maximum at the inclined track 2°4.6. At this time, the magnetic tape is running at the normal playback speed and the 5-turn head completely traces the inclined track without crossing it, so it is possible to obtain a complete RF multiplied signal that is the same as during normal playback.

Therefore, as shown in FIG. 3(c), the inclined track 2.4.
A write pulse generated at timing 6 (corresponding to FIG. 2(b)) causes the video signal in that field to be stored in the memory 6, and in other fields, the video signal stored in the memory 6 is is output (Fig. 3(d)).

In the above, slow playback at 1/2 speed was explained as an example, but by adjusting the timing of running and stopping the magnetic tape and the writing and reading operations to the memory accordingly, it is possible to achieve 0x speed (still playback). Stepless control is possible from 1 to 1/2 times the speed. 6 Frame-by-frame playback is also possible.

Effect C] As described above, the present invention reproduces a tracking pilot signal recorded on an inclined track on a magnetic tape, generates a tracking error signal by comparing it with a reference pilot signal, and generates a tracking error signal corresponding to the tracking error signal. In a magnetic recording/reproducing device that controls tracking of a rotary head and records/reproduces information on an inclined track using the rotary head, the operation of repeatedly running the magnetic tape for a predetermined length and then stopping is performed, and while the magnetic tape is running, the rotary head records and reproduces information. The generated signal is stored in memory, and when the magnetic tape is stopped, the signal stored in memory is output, so C
Even in devices that control tracking using pilot signals rather than TL signals, slow playback, still playback,
Special playback such as frame-by-frame playback can be performed. Further, a good image can be obtained without using a rotary head whose width is wider than the track width.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the magnetic recording 8 reproducing device of the present invention, and FIG.
The figure and FIG. 3 are the timing charts. FIG. 4 is a block diagram of a conventional magnetic recording/reproducing device, FIGS. 5 and 7 are explanatory diagrams of its tracks, and FIG. 6 is its timing chart. 1... A/D conversion circuit 3... Memory control circuit 4... D/A conversion circuit 5... Low pass filter 6... Digital memory 7... Frequency division circuit 8... Comparison circuit 9... Capstan drive circuit 10... Control circuit 11... Inclined track 12... Audio track 13... Control trunk 31... Oscillator circuit 32... Low pass filter or higher

Claims (1)

[Claims] A tracking pilot signal recorded on an inclined track on a magnetic tape is reproduced, a tracking error signal is generated by comparing it with the reference pilot signal, and the rotation is performed in response to the tracking error signal. In a magnetic recording and reproducing device that controls tracking of a head and records and reproduces information on the inclined track using the rotary head, an operation of repeatedly running the magnetic tape for a predetermined length and then stopping, A magnetic recording/reproducing device characterized in that a signal reproduced by a rotary head is stored in a memory, and when the magnetic tape is stopped, the signal stored in the memory is outputted.