JPS5862985A - Magnetic recorder having time-lapse system - Google Patents

Abstract

PURPOSE:To prevent noise band from being produced on a reproduced screen with long time recording, by repeating running and stopping of a magnetic tape intermittently and recording a recording signal on this tape during the normal running of the tape. CONSTITUTION:A modulated video signal incoming to a terminal 1 is demodulated 3 via an amplifier 2 and given to a switching circuit 4. The circuit 4 supplies a demodulated video signal to a recording amplifier 5 or stops the supply at a prescribed time interval by a command of a microcomputer 10. The video signal amplified at the amplifier 5 is recorded on a magnetic tape 7 with a rotary magnetic head 6. In this case, the video signal is recorded on the tape during the normal running of the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on a so-called time-lapse type video signal focusing recording device that automatically performs intermittent recording, and repeats the running and stopping of a magnetic tape intermittently during long-term recording. By recording the video signal on the magnetic tape during the running period, it can be played back by a playback device for a long time without causing noise on the playback screen even at the same normal tape running speed as during continuous recording. An object of the present invention is to provide a recordable video signal magnetic recording device.

In general, a long-time magnetic signal recording and reproducing device called a time-lapse system samples one field of video signal every 32 or 64 fields, and the normal tape running speed of 1/32 is 1/64. The sampled Eirin signal was recorded on the magnetic tape by running the magnetic tape at a constant speed until the end of recording. Therefore, although this video signal magnetic recording device is not suitable for recording things that operate very quickly, it can also be used for monitoring and recording inside a safe.
Magnetic tape had the advantage of being economically usable for recording that required a long time, such as recording broadcast content from broadcasting stations.

In addition, this long-duration video signal magnetic recording device records one field at a time, so there is a drawback that during playback, interlacing of odd and even fields is not performed and the vertical resolution is IA. If playback was performed at the normal tape speed, a long recording could be compressed and monitored, and the tape could be stopped where necessary to be played back as a still image.

However, in such conventional long-duration video signal magnetic recording and reproducing devices, in the case of playback due to normal tape running stray electricity, for example, in a helical scan type playback device, the tape running speed during recording and the tape running speed during playback are Because of the difference between
The inclination angle of a track recorded on a magnetic tape is different from the inclination angle of a track drawn by a magnetic head during reproduction. Therefore, during reproduction, the magnetic head always reproduces the video signal across recorded tracks that are in contact with each other, so that noise bands occur within the reproduced screen. On the other hand, in the case of still image reproduction, there is usually no difference between the track inclination angle during recording and the track inclination angle during playback, so by appropriately selecting the position at which the magnetic tape is stopped, A clear reproduced image without noise bands can be obtained. In this way, with conventional long-duration video signal magnetic recording and reproducing lids, the tape speed during recording is extremely slow compared to the normal speed, so during playback at normal sweep speed, the magnetic head Since the video signal is reproduced across adjacent recorded tracks, there is a drawback that noise bands occur in the reproduced image.

The present invention is intended to eliminate the above-mentioned drawbacks, and one embodiment thereof will be described with reference to the drawings.

5 is a block system diagram showing an example of the video signal magnetic recording device of the present invention.

, The modulated video signal that enters terminal l passes through an amplifier 2, is demodulated and signal-processed by a demodulator 3, and is supplied to a switching circuit 4, which will be described later. The switching circuit 4 supplies or stops supplying the Cc demodulated video signal to the recording amplifier 5 at regular time intervals in response to instructions from a microcomputer 0 (hereinafter referred to as OPU) to be described later. The video signal amplified by the recording amplifier 5 is recorded on a magnetic tape 7 by a rotating magnetic head 6.

Intermittent recording under the control of the next number 0 PUIO will be explained. When a record button (not shown) is pressed to extend long-term recording, a recording start signal a is supplied from terminals 911, . . . to 0PU1o. In 0PUIO, the registered software program is kicked by this signal heat. This software program includes: - Vertical synchronization signal to be described later - To send a control signal to the switching circuit 4 and motor drive circuit 11 every predetermined pulse count by counting the pulses from the circuit 8. Contains a control program.

First, according to this software program, the CPU 10 supplies a drive command signal to the motor drive circuit 11, and the motor drive circuit 11 rotates the capstan motor 16 in response to this command signal.

In this way, the magnetic tape 7 starts running. At the same time, a frequency generator 15 coaxial with the capstan motor 6 generates a pulse C synchronized with the rotation of the capstan motor 16, and is supplied to the comparison signal generator 14. The comparison signal d from the comparison signal generator 14 is supplied to the phase comparator 13 and the reference signal J
The phase is compared with the reference signal e from the J'f generator 12. When the rotation of the capstan motor 16 increases and becomes equal to the normal tape running speed, and the phase with the comparison signal running reference No. 1ε matches, the phase comparator 13 outputs the control signal f.
is supplied to 0PUIO. On the other hand, upon receiving this control signal f, the CPU 10 switches off! A video signal supply start command signal t is supplied to the S circuit 4. The switching circuit 4 receives this command signal V.
When received, a video signal corresponding to one field is supplied to a recording amplifier 7, and this one field video signal is amplified and recorded on a magnetic tape 7 by a rotating magnetic head 6. The switching circuit 4, which has passed the video signal for one field, sends a recording end signal to 0PUIO.

Upon receiving the recording end signal, 0PU1o supplies a stop command signal value to the motor drive circuit 11, and this command signal 1 causes the motor drive circuit 11 to stop the capstan motor 16.
In this way, the magnetic tape 7 stops running.

On the other hand, the video signal coming into terminal 1 is vertically synchronized! It is also supplied to a well-separated circuit 8, where only the vertical synchronization signal is taken out and supplied to the CPU 10. The CPU 1O counts the number of pulses in the supplied vertical and direct synchronizing signal, and when the counted value reaches a predetermined value such as 32 pulses or 64 pulses, the CPU 10 outputs the next 1 feed) V-domain video signal. In order to record this, a drive command signal is supplied to the motor drive circuit 11. Motor drive circuit 11 is cab 2 tongue motor 16
When the capstan motor 16 reaches the normal rotation speed, the phase comparator 13 outputs the control signal f ('3PU
Supply to 10. Upon receiving this signal f, the CPU 10 sends a command signal t to the switching circuit 4, and upon receiving the command signal f, the switching circuit 4 records an Eirin signal corresponding to the l field.
The video signal for one field is amplified and recorded on a magnetic tape 7 by a rotating magnetic head 6. Switching circuit 4 that passes video signals for one field
supplies a recording end signal to the OPU 10. In addition, a damper 20° tape guide pole 21, 2 is installed on the tape running path.
2.23 is installed, and after recording is completed, the tape guide pole 22
By moving the magnetic tape 7 in the direction of arrow Y,
By moving the capstan motor 16 by a predetermined amount in the opposite direction to the running direction, it is possible to eliminate the occurrence of non-valve portions on the magnetic tape 7 during the rise time until the capstan motor 16 reaches normal rotation. ,,.

In this way, the 0PUIO sends a command signal to the switching circuit 4 and the motor drive circuit 11 every predetermined pulse count value of the vertical synchronizer No. 1, until a stop command signal is received at the terminal 9. The above intermittent recording is repeated.

When a video signal recorded by such a video signal magnetic recording device is played back at the same normal tape running speed as during continuous recording, the inclination angle of the track recorded on the magnetic tape and the magnetic head drawn during playback will change. Since the angle of inclination of the track is the same, a clear screen can be played back without any noise bands occurring on the playback screen.

Note that the recording interval can be determined by arbitrarily changing the predetermined value stored in 0PUIO, or by n times the pulse of the vertical synchronization signal, that is, nXV (V: period of the vertical synchronization signal, n
By supplying the signal k to 0PU10 every time ≧2),
It can be changed freely. Further, the information may be recorded not at regular time intervals but at variable time intervals, such as recording every time an external event occurs. .:□ Also, although the video signal recording in this embodiment was performed for each field, the recording is not limited to this, and may be performed for one frame, or every n fields or n frames (n≧2).

Furthermore, in this embodiment, the capstan motor 16 is driven intermittently, but as a separate aspect, the capstan motor 16 is driven intermittently.
6 always rotates continuously at normal speed, and the capstan motor 1
The tape may be run intermittently by connecting the tape 6 and a pinch roller (not shown) intermittently. Incidentally, in order to form a continuous recording track, the magnetic tape may be rewound by a predetermined amount using idle time when no recording is being performed. As an example of this, damper 20. Instead of providing the tape guide poles 21, 22, and 23, the OPU calculates the drive command signal to the motor drive circuit 11 by taking into account the time interval of the output timing of the stop command signal i, and sends the stop command to the motor drive circuit 11. After outputting signal 1, it is recommended to output a rewinding command signal to rewind by a predetermined amount. It may also be configured in terms of hardware using other electrical circuits.

As described above, the time-lapse magnetic deployment device of the present invention repeats the running and stopping of the magnetic tape intermittently, and the Eirin signal is recorded on the magnetic tape during the normal running period of the magnetic tape. It is possible to record for a long time, and even when the playback device plays back at the same normal tape speed as during continuous recording, it is possible to play back a clear screen without noise bands on the playback screen.

[Brief explanation of the drawing]

The figure is a block system diagram showing one example of the video signal magnetic recording device of the present invention. 4e...Switching circuit, 8...e Vertical synchronization signal separator, lO
...Microcomputer (CPU), 11...Motor drive circuit, 13.00 Phase comparator, 16...
capstan motor.

Claims (1)

[Claims] A time-lapse magnetic recording device that automatically performs intermittent recording is characterized in that the magnetic tape is repeatedly run and stopped intermittently, and a recording signal is recorded on the nuclear magnetic tape during the running period of the magnetic tape. A time-lapse magnetic recording device.