JPH02170789A - Video signal recorder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The invention is EDTV, ACTV.

The present invention relates to a video signal recording device that records high-definition widescreen video signals such as ADTV.

(Prior art) Various improvements have been made to the current color television (TV) system due to recent advances in hardware, and various studies are being conducted on a system that is called the next generation of high-definition TV. has been done.

HDTV exists as one of such high-definition iTVs. The first goal of improving the image quality of HDTV is to improve the horizontal resolution of the luminance signal. That is, while the current horizontal resolution is about 330 lines, this will be increased to about 450 lines and the transmission band will be extended from 4.2 MHz to about 6 MHz. However, in reality 4.5MH2
Since there are audio signals everywhere, it is not possible to simply extend the bandwidth.

On the other hand, the high frequency component from 4.2MHz to 6MHz is "3.58MHz x (16/7) = 8.18MHz
It has been considered to modulate a subcarrier whose phase is inverted for each field and line of z, and multiplex it in the same frequency band as the color signal. In addition, in order to expand the band of color signals or improve the image quality of signals on the transmitting side, we have developed a system that creates interlaced signals from non-interlaced signals, and a system that cancels ghosts that are characteristic of terrestrial broadcasting interference. Improvement items are about to be proposed. This is considered to be the first generation of EDTV, and represents an improvement over current broadcasting.

As a second generation HDTV, 16:9 or 5:3
It is being considered to transmit wide aspect ratio signals such as What is important when carrying out such signal transmission is compatibility with the current NTSC system. A typical second-generation EDTV that is compatible with the NTSC system is ACTV, which was released in 1987 by the David Sarnoff Institute in the United States.
There is. This is a wide screen screen with an aspect ratio of 5:3, consisting of 525 non-interlaced or 1050 2:1 interlaced scanning lines, and by receiving this broadcast with an ACTV receiver. , both horizontal and vertical resolutions are 420
It will be possible to obtain high-quality images that are free from cross-color and dot interference, and at the same time, it will be possible to obtain conventional image quality using current television receivers.

To further explain ACTV, the original signal is a widescreen signal with an aspect ratio of 5:3, consisting of 1125 interlaced lines, 1050 interlaced lines, or 525 non-interlaced lines. think.

The widescreen original image is divided into a central image and left and right side panels, and is further divided into the following four signals through signal processing. This will be explained below based on FIG.

(1) Main signal A The central image signal set to 4:3 is time-stretched to match the screen scanning period of the NTSC system. Next, the low-frequency components of the left and right side image signals are time-compressed and time-axis multiplexed onto the overscan portion of the screen. The band of these signals is limited to 4.2 MHz.

(2) Auxiliary Signal B The high-frequency components of the panel signals on both sides are processed by a three-dimensional filter, NTSC encoded, and expanded to half the time between the a-effect scanning lines. This time stretching reduces the horizontal bandwidth of this component signal to approximately 1.1 MHz.

(3) The auxiliary signal is a 2:1 interlaced signal, approximately 5 to 6.2
MHz brightness details change from 0 to 1 by frequency shift
．． Shifted to 2MH2.

(4) Auxiliary signal D: 2:1 interface auxiliary signal, with scanning line 525
It consists of luminance detail signals in the vertical and temporal directions that are lost when converting a non-interlaced signal into an interlaced signal. This band is limited to 750MHz.

Among the four signals shown above, main signal A and auxiliary signal B pass through filters in the vertical and temporal directions, and auxiliary signal B and auxiliary signal C have amplitudes compressed nonlinearly and phases inverted for each field. , 408 MHz subcarriers are quadrature modulated and then multiplexed onto the main signal A. This multiplexed signal is 4
．． This signal is a 2 MHz baseband signal, and this signal modulates a carrier wave for broadcasting, and on the other hand, it is modulated by an auxiliary signal C with a carrier wave whose phase is orthogonal to this carrier wave, and then multiplexed. This is the outline of ACTV.

Various other methods have been proposed, but these methods use the current NTSC
The basic idea is to multiplex it into the transmission band of the system.

As a video signal recording device for recording multiplexed wide signals as explained above, there is a 1-inch C format broadcasting VTR.
There is no channel on which to record the CTV auxiliary signal. In addition, as an attempt to record the first generation HDTV, for example, 'An experimental
color-undcr VCRfor IDTV/
EDTV 5ystell (IEEE vol, 3
4 no, IFebr, 198g) is known.

Figure 7 is a diagram to briefly explain the above-mentioned VCR. First, the EDTV signal input manually is filtered through a low-pass filter (LPF).
11 and a bandpass filter (BPF) 12 in parallel, and the 4.2MHz band of the input HDTV signal is
It is separated into a low frequency component of 0 to 3 MHz and a high frequency component of 3 to 4.2 MHz.

Then, the low-frequency component signal is subjected to pre-emphasis in a low-frequency signal processing circuit 13, further subjected to FM modulation, and a high-pass filter (HPF) 14 cuts off the low-frequency component. Further, the output signal from the band pass filter 12 includes a color signal and a luminance signal, and this signal is subjected to low frequency conversion in a high frequency signal processing circuit 15, and is filtered by a low pass filter (
LPF) 1B. This filter 16 cuts off high frequency components of the combined signal.

The respective output signals from the high-pass filter 14 and the low-pass filter 16 are added in an adder circuit 17, amplified by a recording amplifier I8, and then supplied to a recording head 19 to be recorded on a magnetic tape 20. I come to do it.

FIG. 8 shows the spectrum of signals from each part of the above device, and first, FIG. 8(A) shows the input EDTV signal.

In addition, (B) shows the low-pass filter 11 of the EDTV.
This is the low-frequency component of the signal, and the figure (C) is the high-frequency component from the band-pass filter 12. In these figures, the shaded area is the result of frequency polyphase of the high-frequency components of the color signal and luminance signal. It is.

When reproducing signals recorded in this way, the 9th
This is done using a playback device as shown in the figure.

That is, in this device, the recorded signal of the tape 20 on which the signal has been recorded is read by the playback head 2, and after this read playback signal is amplified by the playback amplifier 22, the low-band signal playback processing circuit 23 converts the signal back to the original low-band signal. demodulates to .

Then, the time axis correction circuit (TBC) 24 corrects the fluctuation of the time axis.
Remove by.

On the other hand, the reproduced high frequency signal is transmitted to the high frequency signal reproduction processing circuit 25.
After the frequency is shifted to the original band in , the time axis is stabilized in the same manner as described above in the time axis correction circuit (TBC) 2B. The FM-modulated low-frequency signal and the frequency-converted high-frequency signal thus obtained are added together in an adder circuit 27 and output as a reproduced HDTV signal.

As is clear from the above, it is not possible to reproduce a wide screen signal using a color under type home VTR without using a time axis correction device such as a TBC. In the above-mentioned device, when synthesizing the low-frequency signal and high-frequency signal of the reproduced signal and reproducing the original HDTV signal, it is important to match the time axes of the two signals with high precision. Therefore, the TBC circuit inevitably becomes expensive and complicated. This TBC circuit is constructed using, for example, a digital memory or the like, and two systems of such TBCs are required, making the VTR itself complicated and expensive. Furthermore, the low-frequency converted high-frequency signal also contains high-frequency components of the luminance signal. Therefore, in home VTRs that perform guard panless recording, there is no means for removing crosstalk from adjacent tracks, and it is essentially necessary to install a card band.

(Problem to be Solved by the Invention) In other words, with conventional video signal recording systems, it is not possible to reproduce widescreen signals using a color under one type home VTR, and it is not possible to reproduce widescreen signals using a color under one type home VTR. This invention was created in view of the above points, and it was necessary to correct the time axis using a complicated and expensive device such as a TBC.
It is an object of the present invention to provide a video signal recording device that can easily reproduce a wide screen signal without using a time axis correction means such as that described in C. That is.

[Structure of the Invention] (Means for Solving the Problems) That is, in the video signal recording device according to the present invention, when a multiplexed wide video signal is decoded by a decoder, a wideband luminance signal including a side panel signal is generated. , and a color signal that is quadrature-two-phase modulated with a color subcarrier, the luminance signal is FM modulated, and the color signal is low frequency converted, and the two are added and recorded on a tape. .

(Function) In the above device, when converting a multiplexed wide video signal into a wide screen signal, it is converted into a wideband luminance signal that also includes a side panel signal and a color signal that is quadrature two-phase modulated using a color subcarrier. This came to be recorded on magnetic tape in color under one-sided format. Therefore, according to this device, when combining the low frequency component and the high frequency component of the reproduced signal and reproducing the original EDTV signal, there is no need to match the time axes between the two signals with high precision, and the adjacent track With regard to crosstalk, conventional processing such as PS (phase shift) processing is possible, and there is no need to newly set a guard band on the tape format. It is also possible to ensure upward compatibility with home VTR standards that are currently widely used, such as the VHS standard.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows its configuration, and an NTSC or multiple wide input video signal is supplied to a signal separation circuit 31. This signal separation circuit 31 separates the input signal into three types of signals.

These three types of signals are a luminance signal YN with an aspect ratio of 4:3.
and a quadrature two-phase modulated color signal C with an aspect ratio of 4:3.
N1 is a signal TN that further includes a side panel signal, a high frequency component of a luminance signal, etc.

The three types of signals outputted from the signal separation circuit 31 are supplied to a decoder 32 and decoded to obtain a wide screen luminance signal YW1 and a wide screen color signal Cw.

Then, one of the signals YN and cN obtained from the signal separation circuit 31 and the signals Yw and CW obtained from the decoder 32 is selected by selection switches 331 and 332, and the signal selected by the switch 331 is a luminance signal. The signal supplied to the signal processing circuit 34 and selected by the switch 332 is supplied to the color signal processing circuit 35.

Here, the changeover switches 331 and 332 select the output signals Yw and CW from the decoder 32 when the human input signal is a multiplex wide signal, and select the output signals Yw and CW from the signal processing circuit 32.
and 35 are controlled in an interlocked manner.

The luminance signal processing circuit 34 performs FM modulation on the signal selected by the changeover switch 331, and the color signal processing circuit 35 performs low frequency conversion on the signal selected by the switch 332. The signals processed in both signal processing circuits 34 and 35 are supplied to an adder circuit 36 and added, and after being amplified by a recording amplifier circuit 37, they are recorded on a magnetic tape 39 by a recording head 38. .

FIGS. 2A and 2B show the spectrum of the widescreen luminance signal YW% and the widescreen color signal CW, respectively, when the input signal is a multiplexed wide signal. Here, wide screen luminance signal YW
is a signal to which a high-definition signal of 5 to 6 MHz multiplexed on the spatial domain is also added, and the wide screen color signal Cw is a signal with a color subcarrier frequency f sc (for example, 3.58 MHz) at a right angle This is a two-phase modulated signal.

FIG. 3 shows an example of frequency allocation of recording signals in a VTR, and the low range color signal frequency fs is
Assuming that it is 40 fh as in the 8 standard, the color signal band can only be about ±500 MHz. Therefore, for example, in the case of a signal with an aspect ratio of 5:3, when converted to a signal with an aspect ratio of 4:3, only 415 color signal bands can be obtained, and the minimum 500X (5
/4) = 625KHz" is desired. For this reason, for example, the color signal frequency fs is increased by 10fh to 50 fh. Setting the color signal frequency fs to an integral multiple of fh is due to the PS processing logic. This is to preserve it.

In order to set the signal band of the FM signal to 6.2 MHz, for example, 7.6 MHz is set as the sync chip frequency, which is increased by 2 MHz from 5.6 MHz of the 5-VHS standard. Therefore, the carrier frequency of the 100% white signal is 9.6 MHz. In this case, the C/N deterioration due to carrier up of 2 MHz is about 3 dB.
An improvement can be made by using a metal tape that can be expected to improve N. In this way, a frequency allocation mode with an improved reproduction signal band is set for the 5-VHS standard.

Also, increase fs even more! Signal band: 1.5MHz
It is also possible to improve the image quality by taking f
Set s to 100fh and secure a band of 1.5MH2.

In this case, f S is 1.57 MHz, the sync chip frequency is 9.2 MHz, and the deviation is 2 M
It may be set to Hz. Therefore, the carrier frequency of the 100% white signal is 11.2 MHz.

To reduce C/N deterioration due to 3.6 MHz FM carrier increase, use vapor-deposited tape, which is expected to improve C/N even more than metal tape, or use 5-VHS tape and double the cylinder rotation speed. This will be supported using the segment recording method. Then, in the same manner as described above, a frequency allocation mode as described above is set for the 5-VH3 standard in which the reproduced signal band is improved.

Next, a means for setting a mode in which the signal carrier frequency is increased with respect to the above-mentioned 5-VH8 standard will be described.

First, the increase in the FM carrier frequency is the current 5-VH
This can be addressed by increasing the input DC level of the FM modulation circuit, as is also used in 3-system VTRs.

Regarding color signals, this is possible by using a circuit device as shown in FIG. To explain the case where Y/C separate input used in the 5-VH8 standard is used in such a circuit device, first of all, in a color under one-type VTR, the luminance signal Y is passed through a low-pass filter (L P F) 50, is supplied to the FM modulator 52 via the pre-emphasis circuit 51, and is subjected to FM modulation. During this FM modulation, the FM carrier frequency, deviation, etc. are changed using a mode control signal (CTL). The FM modulated signal is sent to the recording amplifier 5 via the FM filter 53.
4 and is then supplied to the recording head 55.

On the other hand, the color signal C is a band pass filter (B P F) 5
After band limiting is applied at B and low-pass conversion is performed by a low-pass converter 57, the signal is supplied to a low-pass filter (LPF) 58,
Only the low frequency components are extracted, added to the FM modulated signal of the luminance signal, and supplied to the recording head 55 to be recorded on tape.

Next, we will discuss the creation of an idler signal for converting the color signal to a low frequency. First, the horizontal synchronization signal is extracted from the luminance signal Y by the horizontal synchronization separation circuit 59, and this signal is sent to the multiplier 6.
When it is 0, it is a 40fh signal. This signal is the phase shifter 61
, the output fh from the horizontal synchronization separation circuit 59,
A PS logic is configured using a 30 Hz rectangular wave synchronized with the rotation of the video head obtained from the input terminal B2 as a control signal.

The output signal from the phase shifter 81 is multiplied by the signal selected by the changeover switch 64 in the frequency converter B3 to form an idler signal. Here, the changeover switch 64 has first and second local oscillators 65 and 6B.
The selector switch 64 is configured to have its switching selection position set by the control signal CTL. The first local oscillator 65 is “(455/2)”
fh'', the second local oscillator 66 is (455/2)
Of course, it is also possible to add a higher frequency by the frequency increase of fs (signal multiplication), such as "fh +10fh".Also, the multiplier 80 is shown in the state of "40" times, but this is It may be possible to switch to "50" multiplication or "100" multiplication.

Next, the configuration of the multiplexed signal decoder 32 will be explained based on FIG. 5. That is, a broadcasted RF multiplied signal is received, and a baseband demodulation circuit 71 constituting the RF multiplied signal tuner demodulates the baseband signal into a main signal and a helper signal using synchronous detection. The main signal is separated into a main NTSC signal and a multiplexed signal in a multiplexed signal separation circuit 72, and subjected to signal processing. And the above main NTS
The C signal is converted into a luminance signal YN by the NTSC Y/C separation circuit 73.
and color signal CN.

On the other hand, the separated multiplexed signal is processed in a signal demultiplexing circuit 74 for side high frequency signals (SP flaw signal and brightness high frequency signal YH).
The side high frequency signal (SP) is separated and demodulated into a side high frequency signal Ys and a side high frequency color signal CS in a side panel signal demodulation circuit 75. And the above signal Ys
and the luminance signal YN from the Y/C separation circuit 73,
A signal synthesis circuit 76 synthesizes the wide screen luminance signal Yw.

This wide screen luminance signal Yw is a signal having a wide aspect ratio, and a signal is obtained by frequency-converting the luminance wide area signal YH using a Ysul adjustment circuit 77, and is added to the output signal from the Yw synthesis circuit 76 and an adder 78. Then, the final luminance signal YW is output.

Color signal C which is the output signal from the Y/C separation circuit 73
N and the side high-frequency color signal Cs are the CW signal synthesis circuit 7.
9 to obtain a wide screen color signal Cw.

By configuring the multiplexed signal decoder 32 in this way, the luminance signal (band 0 to 6...
2MHz) Yw and a color signal Cw, which is also a wide screen signal, can be obtained. Then, the wide screen signals of these component signals are transferred to the VTR.
can be recorded. It is also possible to ensure upward compatibility with, for example, 5-VHS or VHS system VTRs currently in use. Note that the helper signal can be recorded and reproduced using a deep recording method or the like.

[Effects of the Invention] According to the video signal recording device according to the present invention, it is possible to record and reproduce multiple wide video signals and current broadcasting signals (NTSC), and in particular, the configuration is simplified. It can be made inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining a video signal recording device according to an embodiment of the present invention, FIG. 2 is a diagram showing a spectrum of an input signal in the device of the embodiment, and FIG. 3 is a spectrum of a recording signal. FIG. 4 is a circuit configuration diagram for explaining the color signal recording circuit section in the above embodiment, and FIG.
The figure is a block diagram for explaining the multiplexed signal decoder in the device of the above embodiment, FIG. 6 is a block diagram for explaining the principle of general ACTV signal processing, and FIG. 7 is a block diagram for explaining the conventional recording device. , FIG. 8 is a diagram showing the signal spectrum of the above device, and FIG. 9 is a configuration diagram illustrating an example of a conventional reproducing device. 31... Signal separation circuit, 32... (multiple signal) decoder, 331.332... Changeover switch, 34...
- Luminance signal processing circuit, 35... Color signal processing circuit, 38
...recording head, 39...magnetic tape.

Claims (2)

[Claims] (1) A decoder that decodes a multiplexed wide video signal to obtain a wideband luminance signal and a chrominance signal, which are wide screen signals with a wide aspect ratio, and an emphasis circuit that emphasizes the high frequencies of the wideband luminance signal obtained from this decoder. A luminance signal processing circuit that later performs FM modulation, a color signal processing circuit that converts the color signal obtained from the decoder to a low frequency, and a luminance signal processed by the luminance signal processing circuit and subjected to FM modulation and the color signal processing circuit. and an addition means for adding the color signal which has been low-frequency converted by the addition means, and supplies the signal added by the addition means to the recording medium,
A video signal recording device characterized in that it records multiple wide video signals. (2) The decoder that decodes the multiplexed wide video signal includes a multiplexed signal separation circuit that separates the multiplexed signal from the multiplexed wide video signal, and a luminance signal that is a constituent element of the main signal separated by the multiplexed signal separation circuit. and a Y/C separation circuit that separates color signals; and a signal separation circuit that separates high-frequency components of a side panel signal and a luminance signal, which are components thereof, from the multiplexed signal separated by the multiplexed signal separation circuit. A side panel signal demodulation circuit which performs time axis conversion and demodulation of the side panel signal separated by this signal separation circuit, and further obtains a high frequency luminance signal and a color signal of the side panel signal; a luminance signal synthesis circuit that synthesizes the luminance signal of the main signal obtained by the above-described main signal and the high frequency signal of the side panel signal obtained by the side panel signal demodulation circuit, and generates a wide screen luminance signal by also adding time axis conversion. , addition means for adding the high-frequency component of the luminance signal separated by the signal separation circuit and the wide screen luminance signal, the color signal of the main signal separated by the Y/C separation circuit, and the side panel signal. 2. The video signal recording apparatus according to claim 1, further comprising a color signal synthesis circuit that synthesizes the color signals obtained by the demodulation circuit and performs time axis processing to generate a wide screen signal.