JPH0564152A - Recording and reproduction device for video signal - Google Patents

Abstract

(57) [Summary] [Object] The present invention detects the field frequency of a recording signal at the time of recording, multiplexes data indicating the field frequency into a video signal and records it, and detects by detecting this at the time of reproduction. An object of the present invention is to provide a VTR in which reproduction is performed at the same field frequency as that of time and there is no change in time between recording and reproduction. [Structure] A recording unit comprising a detection means for detecting a field frequency of a recording signal and a means for adding data according to the detection result to the video signal, and a detection for detecting a field frequency multiplexed in the video signal during reproduction. And a reproducing time axis reference generating circuit that is switched according to the detection result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a VTR for recording / reproducing video signals.

[0002]

2. Description of the Related Art Video signals include a plurality of signals having similar field frequencies but different field frequencies. For example NTSC
The field frequency of the television signal is 59.94 Hz
In the monochrome mode, 60 Hz is used.

There are also two types of high-definition TVs, 1125 lines at 60 Hz and 1125 lines at 59.94 Hz. The difference between these frequencies is 50 PAL signals.
Since the difference between the Hz and the NTSC signal of 59.94 Hz is not so large, it is usual that both signals can be recorded in the same VTR.

However, during reproduction, no matter which frequency is used for recording, the same frequency, for example, 59.
Played back at 94 Hz.

[0005]

A field frequency of 5
VTR for recording NTSC video signals at 9.94Hz
When a monochrome video signal having a field frequency of 60.00 Hz is input, the drum servo of the VTR rotates the rotary head at 30.00 revolutions per second in synchronization with the input signal to perform recording.

By the way, regardless of the recorded signal, 59.94H, which has the same field frequency as the color signal during reproduction, is reproduced.
Played back at z. This is because the original field frequency of the recorded signal cannot be known during reproduction.

In this case, the recording field frequency is 60.0
Since the monochrome signal which was 0 Hz is reproduced at 59.94 Hz, there is a problem that the reproduction time becomes longer than the actual time.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a video signal recording / reproducing apparatus capable of reproducing at the same field frequency as the recorded field frequency. ..

[0009]

In order to achieve this object, the video signal recording / reproducing apparatus of the present invention detects and detects the field frequency or horizontal frequency of the video signal to be recorded by the frequency detecting means during recording. A means for superimposing and recording an instruction signal corresponding to the result on the video signal, a detecting means for detecting a signal for indicating a field or a horizontal frequency superimposed on the video signal during reproduction, and a plurality of time base reference oscillators. According to the output of the detection means, a plurality of time axis reference oscillators are switched to perform reproduction.

[0010]

With the above-described structure, at the time of reproduction, the signal indicating the field frequency at the time of recording recorded on the tape is detected and the reproduction time axis reference corresponding to this is used. Can be the same.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A video signal recording / reproducing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a recording apparatus according to an embodiment of the present invention. In FIG. 1, the video signal input from the input terminal 1 is input to the sync separation circuit 2 to detect a vertical sync signal.

The frequency of the vertical synchronizing signal is detected by the frequency detecting circuit 3, and the field frequency instruction signal corresponding to the frequency is multiplexed with the video signal by the memory 4 and the switch 5. The multiplexed signal is further modulated by the FM modulator 6 and recorded on the tape 8 by the rotary head 7.
Further, the vertical synchronizing signal is supplied to the drum servo 9 as a reference of the rotation phase as in the case of the normal VTR, whereby the rotary head 7 rotates in synchronization with the field frequency of the input video signal. The frequency may be detected by directly detecting the field frequency or by detecting the horizontal frequency. Further, the detector can be easily configured with a general frequency counter for detecting a frequency or a time measuring device for measuring a period.

FIG. 2 shows an example of a field frequency instruction signal added according to the field frequency. A positive pulse 10 is added during the vertical blanking period.

In this example, the H level is generated from the memory 4 when the field frequency of the video signal to be recorded is 60 Hz, and the L level is generated from the memory 4 when the field frequency is 59.94 Hz. In the figure, 11 is a negative horizontal synchronizing signal, and 12 is a video signal.

When there are more than two types of frequencies to be distinguished, H and L alone are insufficient, so a 2- or 3-bit field frequency indicating signal may be used. Although the instruction signal is generated by the memory in the embodiment, any method may be used as long as the same instruction signal can be generated. The waveform is also an example, and the same effect can be obtained by using any waveform as long as it can be easily detected during reproduction.

FIG. 3 is a block diagram of a reproducing apparatus according to an embodiment of the present invention. The signal recorded on the tape 14 reproduced by the rotary head 13 is demodulated by the FM demodulator 15 to detect the field frequency indicating signal.
6 is input.

The time base transmitter is a field frequency 5
First reference oscillator 17 for generating 14.318 MHz for 9.94 Hz and 14. for field frequency 60 Hz.
There is a second reference oscillator 18 that produces 333 MHz,
When the field frequency indicating signal multiplexed into the video signal is L, the switch 19 switches the time base oscillator to 14.318 MHz for the field frequency 59.94 Hz, and when H, the switch 19 switches the field frequency 60.
It is switched to 14.333 MHz for Hz.

The time axis reference output switched by the switch 19 is divided by the frequency divider circuit 238875 into a reference signal of about 59.94 Hz or about 60.00 Hz and supplied to the drum servo 21. As a result, the rotary head can rotate at the number of revolutions corresponding to the field frequency instruction signal multiplexed in the video signal, that is, at the same number of revolutions as when recorded. The other switch 1
The output of 9 is sent to the reproduction processing circuit 22 and used as a clock of the digital circuit and as a reference of the reproduction clock of the time base collector. This does not have to be specifically used in a consumer VTR without a time base collector.

At the time of reproduction, the same effect is obtained when the time base oscillator operates in a so-called genlock mode in which the phase and frequency are used in synchronization with the video signal input from the outside. However, in this case, when reproducing a tape having a frequency of 60 Hz, synchronization cannot be achieved unless an external signal of 60 Hz is used for genlock.

[0021]

As described above, according to the present invention, since the reproduction can be performed at the same field frequency as the recorded field frequency, the recorded time and the reproduction time are the same and the reproduction can be performed at an accurate time. Becomes

[Brief description of drawings]

FIG. 1 is a block diagram showing a recording apparatus according to an embodiment of the present invention.

FIG. 2 is a signal waveform diagram recorded by a recording device according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a reproducing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 2 sync separation circuit 3 frequency detection circuit 4 memory 5 switch 7 rotary head 9 drum servo 16 detection circuit 17 59.94 Hz reference oscillator 18 60 Hz reference oscillator 20 frequency divider circuit 22 reproduction processing circuit

Claims (4)

[Claims] 1. A frequency detecting means for detecting a field frequency or a horizontal frequency of a video signal to be recorded, and a means for superposing a field or horizontal frequency indicating signal corresponding to a detection result on the video signal. Video signal recording device. 2. The video signal recording apparatus according to claim 1, wherein the field or horizontal frequency instruction signal is superimposed as a pulse-like signal in a vertical blanking period of the video signal. 3. A detection means for detecting a field or horizontal frequency instruction signal superimposed on a video signal, a plurality of time base reference oscillators, and a switch for switching the time base reference oscillator by the output of the detection means. An apparatus for reproducing a video signal, wherein a reproduction standard of the video signal is determined by switching the switch. 4. A recording / reproducing apparatus for a video signal, comprising the recording apparatus according to claim 1 and the reproducing apparatus according to claim 3.