JPS63257396A - Video signal recording system - Google Patents

Abstract

PURPOSE:To attain recording with broad band also a chrominance carrier signal by using effectively a band arranged with a high frequency luminance signal in a recording signal in recording a broad band video signal. CONSTITUTION:The base band width of a high frequency luminance signal YH is 4.2-6.3MHz, that is, 2.1MHz and it is subject to frequency interleaving multiplex with a chrominance carrier signal to treat the result as a single signal, then the band width of the chrominance carrier signal is extended up to 2.1MHz. Thus, as to the lower side band of the chrominance carrier signal relating to a color difference signal (2R-G), no band limit is required. Thus, a multiplex signal between a chrominance carrier signal C and a high frequency luminance signal YH' outputted from a mixer 121 is fed to a frequency converter 122 and the result is frequency-converted so that the carrier frequency fLSC is nearly 700kHz. Thus, the band of the chrominance carrier signal is also widened.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a video signal recording system, and particularly to a system for capturing a video signal of a wide area and recording it on a recording medium.

<Prior art> In recent years, a wideband television signal, so-called Ex, which has a wider band and is compatible with the current television signal than the television signal based on the current NTSC system, has been developed.
Tended Definition method (hereinafter simply referred to as ED method, television signal based on ED method is
DTV signals) have been proposed. For example, this is 1
This was published in the July 19983 Technical Report of the Institute of Electrical Communication Engineers, C583-61, by Mr. Hirano, Fukinuki, ``Proposal of a high-definition TV system with complete communication capability.''

Regarding the specific transmission method, please refer to the 1981 National Conference of the Institute of Electrical Communication Engineers, 514-11, 514-1
This has been published in ``Three-dimensional signal processing for high-definition TV system with perfect communication'' by Mr. Hirano et al.

<Problems to be Solved by the Invention> By the way, assuming a VTR that records and reproduces the above-mentioned EDTV signal, if single channel recording is to be achieved, the band of the recording signal must be kept as small as possible.

In view of the above-mentioned background, it is an object of the present invention to provide a video signal recording system that effectively utilizes the band and records not only the luminance signal but also the color signal as wide as possible when recording a wideband video signal. With the goal.

Means for Solving the Problems> To achieve this purpose, the system of the present invention includes an imaging means for converting an optical image into an electrical signal, and a broadband luminance control based on the electrical signal output from the imaging means. means for forming a signal, means for separating the broadband luminance signal into a low-band luminance signal and a high-band luminance signal, and a carrier color based on the electrical signal and having a bandwidth according to the bandwidth of the high-band luminance signal. means for forming a signal, means for forming a multiplexed signal by multiplexing the high frequency luminance signal and the carrier color signal, means for frequency modulating the low frequency luminance signal, and means for frequency modulating the low frequency luminance signal; means for converting the frequency of the multiplexed signal so that it is distributed on the low frequency side; mixing means for mixing the frequency-modulated low-frequency luminance signal and the frequency-converted multiplexed signal; and a recording medium for recording the output signal of the mixing means. It consists of means for recording on the top.

Effects> According to the system with the above configuration, both signals exist over the entire region of the multiplexed signal of the high frequency j11 signal and the carrier color signal.
It is possible to make effective use of the recording band, and in particular, it is possible to widen the band for color signals. Furthermore, since the high-frequency luminance signal and the carrier color signal can be treated as a single signal, it is possible to suppress the widening of the recording signal.

<Example> A VTR as an example of the present invention will be described below.

First, the HDTV that the VTR of this embodiment attempts to record and reproduce
A signal will be explained by taking one transmission method as an example. Fig. 5 is a diagram showing the configuration of the transmission side of the HDTV signal, Fig. 6 is a diagram for explaining the bands of each component signal of the HDTV signal to be transmitted with the configuration of Fig. 5, and Fig. 7 is the actual configuration. 1 is a diagram showing the frequency allocation of an HDTV signal (hereinafter referred to as an encoded HDTV signal) transmitted to the HDTV signal. It is assumed that the horizontal and vertical scanning frequencies of the HDTV signal handled in this embodiment are the same as those of the NTSC signal.

A luminance signal Y having a baseband band of 6.3 MH as shown in FIG. 6(a) is input to the input terminal 1 of the younger brother 5. Further, the color difference signals I and Q have bands of 1.5 MH2, 0, and 5 MH, respectively, as shown in FIG. 6(b).
The signals are input to input terminals 2 and 3, respectively.

Both I and Q color difference signals are supplied to a quadrature two-phase modulation circuit 5, and a color subcarrier reference signal of frequency fsc input from a terminal 4 and a color subcarrier reference signal of a frequency fsc input from a terminal 4 and a 90° phase shift circuit 6 convert the color subcarrier reference signal to a 90° phase shift circuit 6.
The phase-shifted signal undergoes quadrature two-phase modulation as is well known, and a carrier color signal (chroma signal) C is obtained. This chroma signal C is band-limited by a bandpass filter (BPF) 7,
It is supplied to the adder 15 at the subsequent stage.

On the other hand, the luminance signal Y is supplied to a bypass filter (HPF) 8 that passes only signals of 4.2 MH or higher, and only its high frequency component Y□ is extracted and input to a subtracter 9. As a result, only the low frequency component YL of the luminance signal Y is obtained from the subtracter 9.

The amplitude of the aforementioned color subcarrier reference signal is multiplied by, for example, 016 times in the coefficient circuit 10. This signal and the signal obtained by inverting this signal by the phase inverter 11 are connected to the switch SW.
is alternately supplied to the multiplier 13 every field period. Reference numeral 12 denotes a terminal to which a rectangular wave having a cycle of l frames that is inverted every l field period is input, and the switch SW is controlled by this rectangular wave.

The multiplier 13 inverts the phase of the high-frequency luminance signal Yu with respect to the color subcarrier every field. are used to form carrier high-band luminance signals Y,,'. The carrier high-frequency luminance signals Y,,' have a spectrum shifted by 30 Hz with respect to the chroma signal C, as will be described later.
, 1' are limited to a band of 4.2 MH or less, and then mixed with the aforementioned chroma signal C in an adder 15.

The signal mixed by this adder 15 is filtered by a spatio-temporal filter I
A low-band luminance signal Y1.1 which is supplied to an adder 18 via I17 and passed through a spatio-temporal filter 116; The encoded ED of the frequency allocation shown in FIG.
The signal is output from terminal 19 to the transmission line as a TV signal.

Here, regarding the spectrum arrangement of this encoded HDTV signal, Figs. 9 (A) to (C) and Fig. 10 (A)
This will be explained using (D).

Figures 9(A) to (C) are one-dimensional representations of the spectral distribution of encoded HDTV signals;
D) is a three-dimensional representation of this.

As shown in FIG. 9(A), YL and C+Y11' are frequency interleaved with each other with respect to the horizontal scanning frequency (fH). Is this the frequency of the color subcarrier f'Jc?
, fsc='Af.

This is due to the relationship (2n-1) (n is a natural number). FIG. 9(B) is an enlarged view of FIG. 9(A) regarding C and YL. Frame frequency f, (=30H2)
Since f II has the relationship f□=fr (2m l) (m is a natural number), fsc='Afr (
2i 1) (i is natural a), YL and C have spectra at positions shifted by 3 Afr, and the vertical scanning frequency a f v (=60 Hz) is also in a frequency interleaved relationship. By the way, since C has a correlation in the time direction for each l field, the spectra are arranged every 60H2 around the peak of the spectrum in the frequency domain of each f, minute. If we assume that the spectrum of every 60H2 arranged around the peak of the spectrum of C in the adjacent 10-minute frequency region does not spread into each other's bands, then every 30H2 as shown in t59 diagram (B). In the 30 Hz frequency region between the YL spectra arranged in , every other C spectrum is arranged. That is, the 30 Hz spectrum region where the C spectrum was not placed was conventionally vacant. That is, Y and Z are arranged in this vacant 30 Hz spectrum region. This situation is shown in Figure 9 (C
) is a diagram showing only the arrangement of C and Y11' when the above spectrum arrangement is expressed in three dimensions.
Figure (B) is a front view of a solid that includes Y u and Y L, as seen from the time axis frequency direction, and Figure 10 (
C) is a plane (X
), and FIG. 1O (D) is a cross-sectional view in the plane (Y) where the horizontal frequency of the assumed solid is y. In FIGS. 1.theta.(A) to (D), "le" indicates the frequency in the horizontal direction of the screen, "v" indicates the frequency in the vertical direction of the screen, and "f" indicates the frequency in the time axis direction.

Therefore, the liquid discharge area of the spatio-temporal filter 116 in FIG. 5 is as shown by the hatched area in FIG. 8(A). In FIG. 8(A), the vertical axis represents the frequency in the vertical direction of the screen, and the horizontal axis represents the frequency in the time axis direction. Further, the filtering area of the spatio-temporal filter l117 is as shown by the shaded area in FIG. 8(B). These spatio-temporal filters are formed using one horizontal scanning period delay line or one frame delay device, as is well known. This encoder H
The one-dimensional (horizontal) frequency of the DTV signal is YL 0 to 4.
．． 2MHz, YIl is 2.1-4.2MH, C is 3.
It has a bandwidth of 1 MHz centered around 58 MHz.

This embodiment assumes the above-mentioned transmission method, and the ED
The present invention is applied to a device that integrates a TV camera and a VTR. FIG. 1 is a block diagram showing a schematic configuration of a camera-integrated VTR as an embodiment of the present invention.

In Figure 1, lot is baseband 0~e, 3MH,
This is an imaging unit that can obtain a luminance signal Y having the above band and a modulated line-sequential color difference signal. It consists of a CCD including In Figure 2, G (green), Ye (lA) Cy (cyan),
This is a color separation filter such as M (magenta). This imaging unit 101 is driven by a drive circuit 102 that receives a pulse signal from a pulse generator 127 as input. Figure 3(a)
, (b) show the spectral distribution of signals outputted line-sequentially from the imaging unit 101. Modulation component (G-2R) in the figure.

The modulated carrier frequency f5 of (2B-G) is 6.3 MH or more. This frequency fs is determined by the pixel pitch of the CCD.

A low-pass filter (LPF) 103 filters a luminance signal within a band of O to a, 3MH2 from the output of the imaging unit l (Fig. 3(C)
PF10
The output signal of 3 is further supplied to HPF104, and the output signal of 4.2M
H, or higher high-frequency luminance signal Y1. or can be obtained. This high frequency luminance signal Y u is supplied to a subtracter 105 and subtracted from the luminance signal Y to obtain a low frequency luminance signal YL.

The low-band luminance signal YL is FM-modulated by the FM modulator 106 and output to the FM receiver arranged in a band as shown by FM-YL in FIG.
Obtain a modulated low-band luminance signal. On the other hand, the high-frequency luminance signal Yll obtained by the HPF 104 is multiplied by a carrier signal, which will be described later, in a multiplier 107 to produce a carrier high-frequency luminance signal Y1. ' and
Furthermore, it is supplied to the mixer 121 via the LPF 108.

BPF109 is the above-mentioned modulation component (G-2R) (2B-G
) is separated and supplied to the demodulation circuit llO to obtain a demodulated line-sequential color difference signal.

This line-sequential color difference signal is supplied to a well-known line-to-line timing circuit 111 consisting of an IH delay line and a switch, as shown in FIG. 3(d).
, two types of color difference signals with bandwidths as shown on the left side of (e) are obtained. These are supplied to LPF112 and 113 respectively,
(2R-G) signal: 0~1.5MH2゜(2B
-G) is band-limited to 0 to 0.5 MHz, resulting in a signal having a band as shown on the right side of FIG. 3(d) and (e). These band-limited color difference signals are supplied to a quadrature two-phase modulation circuit 115, where they are quadrature two-phase modulated using two carrier waves, which will be described later, to obtain a band carrier color signal as shown on the left side of FIG. 3(f). This carrier color signal has part of its upper sideband removed by the LPF 114, and is supplied to the mixer 121 as a signal as shown on the right side of Fig. 53(f).

Pulse generator 127 generates a carrier signal at the color subcarrier frequency fsc of the NTSC signal. Quadrature two-phase modulation circuit 11
In step 5, quadrature two-phase modulation is performed using the carrier signal of this frequency a f sc and a signal whose phase is shifted by 90'' by the phase shifter 116. Also, this carrier wave is passed through the amplitude limiter 117 to the switch 119 and A carrier wave signal is supplied to a phase inverter 118, and the polarity is inverted for each field by switching a switch 119 for each field.The frequency of the carrier signal output from this switch 119 is equal to the frequency tsc of the carrier wave. The correction field frequency (30H2 in the case of an NTSC signal) is shifted relative to the carrier color signal C and the carrier high-frequency luminance signal Y1.
7 will be frequency interleaved with respect to the vertical scanning frequency.

Here, the band limitation of the carrier color signal by the LPF 14 will be explained. The baseband bandwidth of the above-mentioned high-frequency luminance signal Y is 4.2 to 6°3MH2, or 2.1MH2.
, and if this and the carrier color signal are frequency interleaved multiplexed and treated as a single signal, the bandwidth of the carrier color signal is also 2.1M)! , it is possible to take up to .

Therefore, in this embodiment, there is no need to perform band limitation on the lower sideband of the carrier color signal related to the color difference signal (2R-G).

A multiplexed signal of the carrier color signal C and the carrier high-band luminance signal Y, ,' output from the mixer 121 is supplied to the frequency converter 122, and the carrier frequency f is supplied to the frequency converter 122. The frequency is converted to approximately 700 KHz. The conversion signal supplied to the frequency converter 122 is a signal of frequency (f sc + f LSC) generated by the pulse generator 127, and the output signal of the frequency converter 122 is horizontally scanned between adjacent tracks by the phase shift circuit 120. These are signals whose phases are suitably shifted so that the frequencies are mutually interleaved.

The output of the frequency converter 122 is 2.2M at the LPF 123.
After extracting only the H2 component, it is mixed with the above-mentioned FM modulated low-band luminance signal YI in a mixer 124 to obtain a recording signal having a spectrum distribution as shown in FIG. In FIG. 4, FC-C is the frequency-converted carrier color signal component, FC-C
-Y++' respectively indicate frequency-converted carrier high-band luminance signal components. In Figure 4, the modulation frequency of FM-YL is 6.1 MHz for the sync chip and 7.1 MHz for the white peak.
, is modulated to sound like a roar. The recording signal output from the mixer 124 is recorded on a magnetic tape 126 via a magnetic head 125.

According to the apparatus of the embodiment described above, when recording a wideband video signal, the recording band can be used effectively and the band of the carrier color signal can also be widened. Further, since the carrier color signal obtained by the quadrature two-phase modulation circuit 115 is subjected to subsequent processing such as frequency conversion without being mixed with the low-band luminance signal, signal deterioration can be reduced.

Incidentally, although the above embodiment has been explained by taking a camera-integrated VTR as an example, the present invention can also be applied to a VTR that records an ED-TV signal transmitted in the form shown in FIG. The cutoff frequency of the BPF that separates the carrier color signal from the ED-TV signal shown in FIG. 7 may be determined according to the band of the high-frequency luminance signal.

<Effects of the Invention> As explained above, according to the system of the present invention, when recording a wideband video signal, by effectively using the band in which the mid-high range luminance signal of the recording signal is allocated, the carrier color signal can also be recorded in a wide band. It became possible to convert and record it.

[Brief explanation of the drawing]

Figure 1 shows a camera-integrated VTR as an embodiment of the present invention.
2 is a block diagram showing the configuration of the color separation filter in the imaging section in FIG. 1, FIG. 3 is a diagram showing the spectrum distribution of the signal in the numbered part of FIG. The figure shows the spectral distribution of the recorded signal by the device in Figure 1, Figure 5 shows the configuration of the ED-TV signal transmitter, and Figure 6 shows the EDTV signal to be transmitted using the configuration in Figure 5. A diagram for explaining the band of each component signal of the signal, Figure 7 is a diagram showing the frequency allocation of the encoded HDTV signal, and Figures 8 (A) and (B) are the characteristics of the spatio-temporal filter in Figure 5. Diagram showing. 9A to 9C are one-dimensional representations of the spectral distribution of the encoded HDTV signal, and FIGS. 10A to 10D are three-dimensional representations of the spectral distribution of the encoded HDTV signal. In the figure, 101 is an imaging unit, 103 is an LPF, and 104 is an HPF.
, 105 is a subtracter, 106 is an FM modulator, 107 is a multiplier, 10B is an LPF, 109 is a BPF, 114 is an LPF
, 115 is a quadrature two-phase modulator, 121 is a mixing circuit, 122
is a frequency converter, 123 is an LPF, 124 is a mixer, 1
25 is a magnetic head.

Claims (1)

[Scope of Claims] Imaging means for converting an optical image into an electrical signal; means for forming a wideband luminance signal based on the electrical signal output from the imaging means; means for separating the high-frequency luminance signal and the carrier color signal; means for forming a carrier color signal having a bandwidth according to the bandwidth of the high-frequency luminance signal based on the electrical signal; and means for separating the high-frequency luminance signal and the carrier color signal into means for forming a multiplexed signal; means for frequency modulating the low frequency luminance signal; means for converting the frequency of the multiplexed signal so that it is placed on the lower frequency side of the frequency modulated low frequency luminance signal; A video signal recording system comprising: mixing means for mixing a frequency-modulated low-band luminance signal and the frequency-converted multiplexed signal; and means for recording an output signal of the mixing means on a recording medium.