KR880000412Y1 - Recording apparatus of colour picture signal - Google Patents

Abstract

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Description

Color video signal recording device

1 and 2 are schematic diagrams showing conventional devices.

3 and 4 is a schematic diagram of an embodiment according to the present invention.

5 to 7 is a schematic diagram showing another embodiment of the device of the present invention.

* Explanation of symbols for main parts of the drawings

1: Input terminal 2, 8, 15: Low pass filter

3: frequency modulator 4, 14, 35: mixer

5, 18: Band filter 6, 16, 46: Frequency converter

7, 7 ', 7 ": Local oscillator 9: Video head for recording

10: video head for playback 11: chariot amplifier

12 high pass filter 13 frequency demodulator

17, 17 ': voltage controlled oscillator 19: burst phase comparator

20: reference oscillator 21, 29: output terminal

22, 25: horizontal synchronous separator 23, 26, 38: phase comparator

24, 27: 1 / n divider 28: Time base collector

30, 36: 1/4 divider 31: Pilot gate pulse generator

32, 39: 1 / (4n-1) divider 33: Gate circuit

34: 3.58 MHz oscillator 37: pilot detector

40, 41: 1/2 divider 42: 40 multiplier

43: PS (phase shift) circuit 44: terminal

45: 455 multiplier

The present invention relates to a color video signal recording apparatus and a recording / reproducing apparatus, and in particular, an object of the present invention is to provide an apparatus capable of effectively utilizing luminance signal components included in a carrier color signal band.

FIG. 1 is a block diagram of a recording system of a conventional low frequency conversion color video signal recording and reproducing apparatus, and FIG. 2 is a block diagram of a reproduction system.

In FIG. 1, a composite color video signal applied to the input terminal 1, for example, NTSC or PAL, is a low-pass filter 2 having a cutoff frequency of about 3 MHz. The luminance signal is supplied to the mixer 4 as a frequency modulated signal whose carrier is frequency-modulated by the frequency modulator 3.

On the other hand, the composite color video signal applied to the terminal 1 is also supplied to the band filter 5 having a normal band of about 3 to 4.2 MH _Z , and the signals of the carrier color signal band are separated, and the signals of the carrier color signal band are frequency. By taking the frequency of the difference of the conversion local signal in the local oscillator 7 as the converter 6, it becomes a frequency conversion signal which makes the low frequency of about 630 KHz the center frequency, for example, and cuts off the frequency about 1.2 MHz. It is supplied to the mixer 4 through a low pass filter 8 having a?, To a recording video head mixed with the frequency modulated signal, and recorded on a recording medium (not shown) such as a magnetic tape.

The recorded signal is reproduced by the reproducing video head 10 in the reproducing system shown in FIG. 2, and amplified to a suitable level as the preamplifier 11, and then having a high pass filter having a cutoff frequency of about 1.2 MHz. The reproduction frequency modulated signal is separated by 12, and the reproduction frequency modulated signal is demodulated by the frequency demodulator 13 and supplied to the mixer 14 as a reproduction luminance signal.

On the other hand, the signal amplified by the preamplifier 11 is also supplied to the low-pass filter 15 having a cutoff frequency of about 1, 2MHz, and the reproduction frequency conversion signal is separated, and the reproduction frequency conversion signal is converted into the frequency converter 16. In this case, the output of the voltage controlled oscillator 17 is used to frequency convert into a frequency band, and is supplied to the mixer 14 through the band filter 18.

The output of the band filter 18 is also supplied to the burst phase comparator 19, compared with the phase of the output of the reference oscillator 20, and by controlling the oscillation of the voltage controlled oscillator 17 by the error output, the reproduction frequency conversion Timebase variations included in the signal are eliminated.

The output of the frequency demodulator 13 and the output of the band pass filter 18 are mixed in the mixer 14 and output to the output terminal 21 as a reproduced composite color video signal.

In such an apparatus, since the high frequency component of the luminance signal is simultaneously included in the signal of the carrier color signal band taken out by the bandpass filter 18, the phase of the high frequency luminance signal component is not preserved at all (recording reproduction). Although the phase is not modulated in phase with the luminance signal which is frequency-modulated and recorded and reproduced in the process, and reproduced as a band, there is a drawback that it becomes practically useless.

The present invention has been made to solve the above-mentioned drawbacks. A band filter for simultaneously extracting a high frequency component of the luminance signal included in the band, a frequency converter for converting an output of the band filter to a frequency band lower than the band of the luminance signal, and each of the frequency converter and the frequency converter. A color video signal recording apparatus having a mixer for mixing outputs for multiple recording, comprising: a horizontal synchronous signal separation circuit for separating horizontal synchronous from the mixed color video signal, and a local oscillation output controlled by a separate horizontal synchronous signal; Having a new local oscillation circuit for generating a phase, the phase-controlled local oscillation output By supplying to the frequency converter, the phases of the high frequency components of the carrier color signal and the luminance signal separated at the same time are kept constant.

In addition, the present invention is a local oscillation output, a local oscillation circuit for generating a local oscillation output having a constant phase relationship with a pulse selected from every m (m is a natural number) of the separated horizontal synchronization signal, and the selected A pilot signal generation circuit for generating a pilot signal for indicating the position of one pulse, and a second mixer for mixing the generated pilot signal with the output of the band pass filter.

The present invention also provides a carrier luminance signal output circuit that separates a luminance signal from a composite color video signal and frequency modulates a carrier wave, and a signal component included in a band of a carrier color signal from the composite color video signal than a band of the luminance signal. A first horn-silver circuit for mixing and multi-recording a first carrier color signal conversion circuit for converting to a low frequency band, an output of the carrier luminance signal output circuit, and an output of the first carrier color signal conversion circuit; A recording circuit portion having a first horizontal synchronous signal separation circuit for separating a horizontal synchronous signal from the composite color video signal, and a first local oscillating circuit for supplying a first local oscillation output to the first carrier color signal conversion circuit; And a reproduction circuit for reproducing the multi-recorded carrier luminance signal and carrier color signal to obtain a reproduction signal, and dividing the carrier luminance signal from the reproduction signal. A luminance signal demodulation circuit for demodulating and demodulating, a second carrier color signal conversion circuit for separating a carrier color signal from the reproduced signal, and converting the carrier color signal into an original band, an output of the luminance signal demodulation circuit, and a second carrier color signal conversion A second mixed circuit for mixing the outputs of the circuits to obtain a reproduction composite color video signal, a second horizontal synchronous signal separation circuit for separating a horizontal synchronous signal from the output of the luminance signal demodulation circuit, and the second A color video signal recording and reproducing apparatus having a reproducing circuit section having a second local oscillating circuit for supplying a second local oscillating output to a carrier color signal conversion circuit, wherein recording is performed in accordance with said first horizontal synchronous signal separating circuit. A first local oscillation output, sanitarily controlled by the separated horizontal synchronizing signal, is generated from the first local oscillation circuit, and is supplied to the first carrier color signal conversion circuit to generate an image. The phase of the high frequency component of the carrier color signal and the luminance signal is maintained in a constant relationship, and during reproduction, the second local oscillation output phase controlled by the horizontal synchronization signal separated by the second horizontal synchronization signal separation circuit is generated. It is generated from the two local oscillation circuits and supplied to the second carrier color signal conversion circuit, thereby maintaining the high frequency component of the luminance signal and the phase of the carrier color signal in the reproduction composite color video signal constantly through the process of recording and reproducing. Let's do it.

Further, at the time of writing, the first local oscillation circuit serves as the first local oscillation output, and is selected from every m (m is a natural number) of horizontal synchronous signals separated by the first horizontal synchronous signal separation circuit. A pilot signal generation circuit for generating a local oscillation output having a constant phase relationship with one pulse to generate a pilot signal for indicating the position of the selected one pulse, and supplying the generated pilot signal to the carrier color signal conversion circuit And a pilot detection circuit which detects the pilot signal recorded at the time of recording at the output of the second carrier color signal conversion circuit, and the output of the detection circuit. And a frequency division circuit for selecting one pulse selected at the time of recording from among m horizontal synchronization pulses output from the second horizontal synchronization separation circuit (m is a natural number), and the division thereof. By supplying the output to the local oscillator, to generate a local oscillator output of the second pulse which is synchronized to the one selected, thereby supplying it to the mixing circuit 14 of the second.

Hereinafter, an embodiment will be described with reference to the drawings.

3 is a block diagram of a recording system of one example of such an apparatus, and FIG. 4 is a block diagram of a reproduction system, in which the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted.

In the recording system shown in FIG. 3, the composite color video signal applied to the input terminal 1 is also supplied to the horizontal synchronous separator 22, and the separated horizontal synchronous signal is supplied to the phase comparator 23. FIG.

The local oscillator 7 'for oscillating the local signal for frequency conversion is configured as a voltage controlled oscillator, the output of which is supplied to the frequency converter 6 and also to the 1 / n divider 24, where 1 / n The signal divided by is controlled by the phase comparator 23 to oscillate the local oscillator 7 '.

With this configuration, the frequency converted signal maintains a constant phase relationship with the composite color video signal.

In the reproduction system shown in FIG. 4, the output of the frequency demodulator 13 is also supplied to the horizontal synchronous separator 25, where the separated horizontal synchronous signal is supplied to the phase comparator 26.

On the other hand, the output of the voltage controlled oscillator 17 is supplied to the frequency converter 6 and also to the 1 / n frequency divider 27, where the signal divided by 1 / n is horizontal in the phase comparator 26. Phase is compared with the signal, and the oscillation of the local oscillator 17 is controlled by the error signal.

By this configuration, the signal of the carrier color signal band taken out from the band filter 18 has a constant phase relationship with the composite color video signal, and the signal of the carrier color signal band of the reproduced composite color video signal taken out from the output terminal 21 is obtained. The high frequency component of the luminance signal included in the signal can be effectively used.

According to this configuration, even if the time axis of the carrier color signal of the reproduced composite color video signal is slightly unstable, the timebase collector 28 corrects the reproduced composite color video signal extracted from the output terminal 21, and then outputs the result. Taking out from the terminal 29, this instability of the time base can be eliminated by a suitable method, so that there is no problem in practical use.

Also, in the case where the composite color video signal input in the first embodiment is NTSC, the input signal subcarrier frequency is 3.579545 MHz, in which case the division of the 1 / n dividers 24, 27 is performed. The ratio n was 267, the oscillation frequency of the local oscillator 7 'was 4.201048 MHz, and the low frequency conversion transmission frequency was set at 621.503 KHz.

According to the apparatus of the first embodiment of the present invention, the composite color video signal apparatus can effectively reproduce the high frequency component of the luminance signal contained in the signal of the carrier color signal band, which is not achieved in the conventional apparatus, from the above-described configuration. This has the advantage that the resolution of the image can be surely improved.

In addition, according to the second embodiment of the present invention, there is provided a device that solves the disadvantage of deterioration of a reproduced image due to remarkable bead noise caused by a modulation distortion component that can occur during recording. An embodiment will be described. In addition, in the same parts as the first embodiment, the same reference numerals will be attached and description thereof will be omitted.

As a countermeasure for the above-mentioned bits, in the second embodiment of the present invention, the low frequency converter carrier frequency f _s

f _s = (k ± 1/4) f _H

Where f _{H is the} horizontal scanning frequency and k is the natural number

To select.

5 is a block diagram of a recording system according to a second embodiment of the present invention, and FIG. 6 is a block diagram of the reproduction system.

In the recording system of FIG. 5, the horizontal synchronizing signal separated as the horizontal synchronizing separator 22 is divided by a quarter divider 30, and is divided into one burst for every four horizontal synchronizing signals, so that the phase comparator and the pilot gate are used. Supplied to the pulse generator 31.

On the other hand, the output of the local oscillator 7 "configured as a voltage controlled oscillator is also supplied to the 1 / (4n-1) divider 23 at the same time as the frequency converter 6 is supplied, where 1 / (4n-1) The phase comparator 23 is phase compared with the horizontal synchronous signal divided into 1/4 of the phase comparator 23. This error signal controls the oscillation of the local oscillator 7 "and is generated by the local oscillator 7". The local signal for frequency conversion has one phase fixed every four horizontal synchronization signals.

The gate pulse from the pilot gate pulse generator 31 is supplied to the gate circuit 33, gates the signal from the 3.58 MHz oscillator 34, generates one pilot signal for every four horizontal synchronization signals, and such a pilot The signal is mixed in the mixer 35 with the signal of the carrier color signal band in the band pass filter 5 and inserted at an appropriate position before or after the color burst signal in the horizontal blanking period for every four horizontal scanning cycles.

In the reproducing system of FIG. 6, the horizontal synchronizing signal separated as the horizontal synchronizing separator 25 is divided into 1/4 in the quarter divider 36. FIG. In this quarter divider 36, the resell signal is extracted as a pilot detector from the output signal of the band pass filter 18, and a pilot signal is supplied every four horizontal scanning cycles.

The output of this quarter divider 36 is supplied to the phase comparator 38, while the output of the voltage controlled oscillator 17 'is also 1 / (4) by the divider 39. 4n-1), the oscillation of the voltage controlled oscillator is controlled by these two phase comparison error signals.

Also in the examples of FIGS. 5 and 6, the local oscillator 7 "is synchronized with one for every four input horizontal synchronization signals, so that these phases have four kinds of degrees of freedom. The pilot signal is superimposed at one position within the four horizontal scanning periods in order to remain.

In reproducing, the pilot signal is detected and one is selected for every four horizontal synchronous signals, where the phase of the local signal by the frequency converter 16 is recorded.

The structure of FIG. 5 and FIG. 6 was made to implement | achieve said Formula (1), and in Formula (1),

K = 40,

f _s = 633.304KHz

f _L = f _c + f _s = 4.212849

f _L : local oscillation frequency

f _c : Color subcarrier frequency 3.579540

Also

f _L = 1/4 × (4n-1) f _H

n = 455/2 + K + 1/2 = 268

Is displayed.

7 is a block diagram of an important part of the third embodiment of the present invention, in which the phases of the carrier color signals are shifted by 90 degrees in opposite directions for each horizontal scanning period in adjacent recording tracks, so-called PS (phase shift). In the case of application in a manner, a local signal supply circuit as a frequency converter (symbol 6 in FIG. 5 and symbol 16 in FIG. 6) is shown.

In FIG. 7, the horizontal synchronizing signal in the horizontal synchronizing separators 22 and 25 is supplied from the 1/2 divider 40, 41 to the quarter divider 30, 36. In addition, it is supplied to the PS (phase shift) circuit 43, it is supplied to the 40 multiplier 45, and is 40 multiplied and is supplied to the PS (phase shift) circuit 43.

The outputs of the 1/4 dividers 30 and 36 are also supplied to the PS (phase shift) circuit 43 as a reset signal, and these signals are mutually connected by the PS direction switching pulses at the terminal 44. A phase shift signal for outputting a shifted phase of the carrier color signal by 90 degrees in the opposite direction to each other in the horizontal scanning cycle is outputted.

The output of the 1/2 divider 40 is 455 multiplied by the 455 multiplier 45 and is supplied to the frequency converter 46, and the output of the PS (phase shift) circuit 43 in such a frequency converter 46. Is frequency converted to a predetermined frequency and supplied to the frequency converters 6 and 16 as local signals for conversion.

When the local signal generating circuit of FIG. 7 is used in the recording system of FIG. 5, the output of the 1/4 divider 30 is supplied to the pilot gate pulse generator 31, and the signal from the 3.58 MHz oscillator 34 is supplied. When the gate signal is gated to generate a pilot signal in four horizontal scanning cycles and used in the reproducing system of FIG. 6, the 1/2 divider 36 (1) is generated by the output of the pilot signal detector 37. / 4 dividers 40 and 41 are reset every four horizontal scanning cycles.

Note that each of the above embodiments uses the horizontal synchronizing signal as quarter division, and is not limited thereto, and any division ratio can be employed as necessary.

Since the device of the present invention is as described above, it improves the resolution of the reproduced image and at the same time reduces the bit noise, improves the image quality of the reproduced image, and is also included in the signal of the carrier color signal band which cannot be used in the conventional apparatus. The high frequency component of the luminance signal can be effectively used to improve the sharpness of the playback screen. Here, one of ordinary skill in the art can change and change the subject innovation without departing from the scope and spirit of the subject innovation.

Claims (2)

A low pass filter (2) for separating the luminance signal from the composite color video signal, a frequency modulator (3) for frequency-modulating a carrier by the separated luminance signal, and a carrier color signal from the composite color video signal and included in the band A band filter 5 which simultaneously extracts the high frequency components of the luminance signal, and a frequency converter 6 for converting the output of the band filter to a frequency band lower than the band of the luminance signal, and each of the frequency modulator and the frequency converter. A color video signal recording apparatus having a mixer (4) for mixing outputs for multiple recording, comprising: a horizontal synchronous signal separation circuit (22) for separating horizontal synchronous from the mixed color video signal and a separate horizontal synchronous signal; New local oscillation circuits 23, 24, 7 '(30, 32, 7 ") generating a phase controlled local oscillation output, and transmits the phase controlled local oscillation output to the frequency converter. And a high frequency component of the carrier color signal and the luminance signal separated at the same time to be kept constant. 2. The local oscillation circuit (30) according to claim 1, wherein the local oscillation output generates a local oscillation output having a constant phase relation with one pulse selected from every m of m separated horizontal synchronization signals (m is a natural number). 23, 32, 7 "), a pilot signal generation circuit 30, 31, 34, 33 for generating a pilot signal for indicating the position of the selected one pulse, and the generated pilot signal to the output of the band pass filter. And a second mixer (35) for mixing.