JPS63131684A - Video signal recorder - Google Patents

Abstract

PURPOSE:To simplify circuit constitution, by separating a video signal to a low-pass luminance signal and the multiplex signal of a carrier chrominance signal and a high- pass luminance signal to be converted, and performing frequency multiplex by performing the frequency modulation of the low-pass luminance signal, and performing the frequency conversion of the multiplex signal on the low-pass area of a low-pass luminance signal to be frequency-modulated. CONSTITUTION:The component (carrier high-pass luminance signal YH'+carrier chrominance signal C) of a television signal inputted to an input terminal 34 is separated by a spatial filter 35, and it is subtracted from the television signal at a subtractor 36, thereby, the low-pass luminanced signal YL can be obtained, and a low-pass luminance signal (FM-YL) to be FM-modulated can be obtained at an FM modulation circuit 38 via an automatic gain control circuit AGC 37. Meanwhile, the component (YH'+C) is frequency-converted so as to become a low-pass chrominance subcarrier at a frequency conversion circuit FC40, and a carrier chrominance signal to be low- pass-converted and a carrier high-pass luminance signal (FC-C&YH') can be obtained at an LPF46. Next, the (FM-YL) and the (FC-C&YH'), after being frequency- multiplexed at an adder 47, are recorded on a magnetic tape 48. In such way, it is possible to record the video signal of wide band with simple circuit constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a video signal recording device, and particularly to a device for recording a wideband video signal.

<Prior art> In recent years, a wideband television signal, so-called Ext.
Ended Definition method (hereinafter simply E
It is called the D method, and the television signal based on the ED method is called ED.
TV signals) have been proposed.

For example, this is the July 1983 IEICE Technical Report, C.
It was announced in ``Proposal of a high-definition TV system with complete communication'' by Mr. Hirano, Fukinuki, 383-61.

Regarding the specific transmission method, please refer to the 1985 General 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 signals, if the recording signal band can be suppressed to the same level as the current VTR for television signals, the head and recording EDTV signals can be recorded and reproduced without increasing the relative speed between the media, and as a result, a mechanical configuration similar to that of current VTRs for television signals can be used.

Furthermore, along with this, there is a demand for a shared device that can similarly record and reproduce current television signals.

In view of the above-mentioned background, it is an object of the present invention to provide a video signal recording method that can record a wideband video signal with a simple circuit configuration without significantly expanding the recording signal band.

<Means for Solving the Problems> With this object in mind, according to the present invention, a low-band luminance signal, a carrier color signal frequency-interleaved with the low-band luminance signal with respect to the horizontal scanning frequency, and a carrier color signal with respect to the horizontal scanning frequency are provided. An apparatus for recording a video signal including a high-band luminance signal frequency-interleaved with the low-band luminance signal and converted to be frequency-interleaved with the carrier chrominance signal with respect to a vertical scanning frequency, the apparatus using screen-to-screen correlation. means for separating the video signal into the low-band luminance signal and a multiplexed signal of the carrier color signal and the converted high-band luminance signal; and means for frequency modulating the separated low-band luminance signal. , means for frequency-converting the separated multiplexed signal to a lower frequency of the frequency-modulated low-band luminance signal, and means for frequency-multiplexing the frequency-modulated low-band luminance signal and the frequency-converted signal; The configuration includes means for recording frequency-multiplexed signals.

In the above configuration, both the carrier chrominance signal and the converted high-frequency luminance signal are frequency interleaved with respect to the horizontal scanning frequency with respect to the low-frequency luminance signal, so it is not necessary to utilize the correlation between screens. , it is possible to sufficiently separate the above-mentioned low-band luminance signal and multiplexed signal using only the intra-screen correlation. As a result, the configuration of the separating means can be extremely simplified, and there is almost no deterioration of the recorded low-band luminance 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. Figure 3 is a diagram showing the configuration of the transmission side of the ED 'TV signal, and Figure 4 is a diagram showing the configuration of the ED 'TV signal transmitting side.
A diagram for explaining the bands of each component signal of the TV signal, FIG. 5 shows the EDTV signal (
FIG. 2 is a diagram showing frequency allocation of an encoded EDTV signal (hereinafter referred to as an encoded EDTV signal). In addition, the ED handled in this example
It is assumed that the horizontal and vertical scanning frequencies of the TV signal are the same as the NTSC signal.

Now, a luminance signal Y having a baseband band of 6.3 MHz as shown in FIG. 4(a) is input to the input terminal 1 of FIG. 3. In addition, the color difference signals I and Q are shown in Fig. 2 (b
) as shown in 1, 5 MHz, 0, 5 MHz, respectively.
They have a band of MHz and 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, which converts the color subcarrier reference signal of frequency fsc inputted from a terminal 4 and this into a 90° phase shift circuit 6.
The phase-shifted signal is quadrature two-phase modulated as is well known,
A carrier color signal (chroma signal) C is obtained.

This chroma signal C has both side band waves of 0 and 5 M, respectively.
The band is limited by a bandpass filter (BPF) 7 to approximately Hz, and the signal 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 MHz or higher,
Only the high frequency component YH is extracted and input to the 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, for example, by 0.6 in the coefficient circuit IO. 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 of one frame period that is inverted every l field period is input, and the switch SW is controlled by this rectangular wave.

The multiplier 13 converts the high-band luminance signal YH into a color subcarrier using a carrier wave μ0 whose phase is inverted for each I field.
A carrier high-frequency luminance signal YH' is formed. This carrier high-frequency luminance signal YH' is 3
It will have a spectrum shifted by 0 Hz,
A low pass filter (LPF) 14 filters the signal YH'
After being limited to a band of 4.2 MHz or less, it is mixed with the above-mentioned chroma signal C in an adder 15.

The signal mixed in this adder 15 is filtered by a spatio-temporal filter [
17 to the adder 18, and the spatiotemporal filter 1
The signal is mixed with the low-band luminance signal YL via the terminal 16 and outputted from the terminal 19 to the transmission line as an encoded HDTV signal with the frequency allocation shown in FIG.

Here, regarding the spectrum arrangement of this encoded EDTV signal, Fig. 17 (A) to (C) and Fig. 8 (A) to
This will be explained using (D).

Figures 7 (A) to (C) are one-dimensional representations of the spectral distribution of encoded HDTV signals, and Figures 8 (A) to (
D) is a three-dimensional representation of this.

As shown in FIG. 7(A), Yt and C+YH' are frequency interleaved with respect to the horizontal scanning frequency (fH). This is because the frequency of the color subcarrier fsc has the relationship fsc=y2fH (2n-1) with respect to fH (n is a natural number). Figure 7 (A) to C
FIG. 7(B) shows an enlarged view of and YL. For the frame frequency fF (=30Hz), fH is fH=
Since there is a relationship fv (2m-1) (m is a natural number),
fsc=! 4fp (2i -1) (i is a natural number), YL and C have spectra at positions shifted by 'A f v, and the vertical scanning frequency fv (=60H
z) is also in a frequency interleaved relationship.

By the way, since C has correlation in the time direction for each field, the spectra are arranged every 60 Hz around the peak of the spectrum in the frequency domain for each fH. If we assume that the spectra of each 60H, z arranged around the peak of the spectrum of C in the frequency region of fH adjacent to each other do not spread into each other's bands, we can obtain the result shown in Fig. 7(B). In the 30 Hz frequency region between the YL spectra arranged every 30 Hz, the C spectrum is arranged every other time. That is, the 30 Hz spectrum region where the C spectrum is not located has conventionally been closed. In other words, this vacant 30Hz
YH' is placed in the spectrum region of . This state is shown in FIG. 7(C).

FIG. 8(A) is a diagram showing only the arrangement of C and YH′ when the above spectrum arrangement is expressed in three dimensions.
B) is a front view of a solid that includes YH and YL as seen from the time axis frequency direction, and Figure 8 (C) is a plane (X) where the horizontal frequency of the assumed solid is X. The cross-sectional view, FIG. 8(D), shows that the horizontal frequency of the above assumed solid is y
FIG. In addition, Fig. 8 (A
) to (D), μ indicates the frequency in the horizontal direction of the screen, ν indicates the frequency in the vertical direction of the screen, and f indicates the frequency in the time axis direction.

Therefore, the filtering area of the spatio-temporal filter 116 in FIG. 3 is as shown by the hatched area in FIG. 6(A). In FIG. 6(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 117 is as shown by the shaded area in FIG. 6(B). As is well known, these spatiotemporal filters include l horizontal scanning period delay lines and l
The one-dimensional (horizontal direction) frequency of this encoded EDTv signal formed using a frame delay device is
4, 2 MHz.

YH' is 2, 1 to 4, 2 MHz, C is 3
, with a bandwidth of 1 MHz centered at 58 MHz.

Next, the configuration of the receiving side that receives this encoded EDTV signal and forms the original component signal again is
As shown in the figure. The encoded HDTV signal input to the terminal 20 via the transmission line is passed through the spatio-temporal filter l117 in FIG.
A spatio-temporal filter lI21 similar to (this filtering region is the first
(C+YH'
) components are separated. On the other hand, this separated (C+YH
) component from the encoded EDTV signal.
By subtracting by 2, the Yt component is obtained. (C+YH
The ``) component is further input to a space-time filter m23 having a filtering band as shown in the shaded area in FIG. 10(B), and only the C component is separated.

Further, this C component is separated from the (C+YH') component by a subtracter 24 to obtain the YH' component.

The carrier color signal C obtained in this way is decoded in the quadrature two-phase demodulation circuit 25 using the decoding reference signal of the frequency fSC generated by the circuit 26 and a signal whose phase is shifted by 90° in the 90° phase shift circuit 27. Obtain I and Q colorimetric difference signals. On the other hand, the carrier high-frequency luminance signal YH' is supplied to a multiplier 31 and converted into the original high-frequency luminance signal YH. The signal multiplied by this multiplier 31 is divided into a coefficient unit 281, a phase inverter 29
．． This is a signal with a frequency fSC whose phase is inverted every 1 fields output from the switch SW'.

YH obtained from the multiplier 31 is a bypass filter (HPF)
After removing components of 4.2 MHz or less at 32, the signal is mixed with Yt at an adder 33 to obtain a wideband luminance signal Y again.

FIG. 1 is a diagram showing a schematic configuration of a VTR as an embodiment of the present invention assuming the above-described transmission signal.

When the aforementioned encoded EDTV signal is input to the input terminal 34, the (YH'+C) component is separated into the spatial filter 35. The characteristics of this spatial filter 35 will be explained below using FIGS. 11(A) and 11(B).

FIG. 11(A) is a diagram showing the filtering area of the spatial filter 35 in terms of the frequency ν in the vertical direction of the screen and the frequency f in the time axis direction. It is not possible to specify the frequency r of the spatial filter 35. FIG. Corresponding to FIG. 5, 2,1 MHz to 4,2
Bandwidth limited to MHz. The spatial filter having the above-mentioned filtering area is, for example, a so-called comb filter using a horizontal scanning period delay circuit, and a filter having a frequency of 2.1 MHz to 4.2 MHz
It can be constructed by a BPF that filters the band between z and C and YH' in the filtering region shown in FIG. 6(B) are all included in the output of this spatial filter.

Now, when considering the use of this spatial filter 35 in place of the spatio-temporal filter having the filtering area shown in FIG. and μ is 2, 1 MHz to 4
, 2 MHz region. However, in terms of images, this area is visually close to a still image and has high frequency components in the diagonal direction of the screen, and this component is extremely small and does not actually pose a problem at all.

Further, in terms of circuit configuration, whereas the spatio-temporal filter requires a delay line of 525 horizontal scanning periods, the spatial filter can be constructed with a delay line of 1 horizontal scanning period, which is extremely advantageous.

In this way, by the spatial filter 35 (YH' 10)
The components are separated, and the (YH' +C) component is further subtracted from the encoded HDTV signal by a subtracter 36 to obtain the Yt component. The YL acid component is inputted to the FM modulation circuit 38 via the automatic gain control circuit (AGC) 37.

In an FM modulation circuit, for example, the sync chip is 6.1MHz.
.

Yt is FM modulated so that the white peak is 7.1 MHz, and the HPF 39 separates only the components of 2.4 MHz or higher to produce an FM modulated low frequency signal with a spectrum as shown in Figure 2 (A). FM-YL is obtained.

The other (YH'-i-C) component is the frequency conversion circuit (
FC) 40, the color subcarrier frequency fsc is approximately 0.7M.
It is frequency-converted to a low band so as to become a low band color subcarrier of Hz (fLSC). The frequency of this f LSC is selected to be an odd multiple of %fH, and consideration is given so that this second harmonic does not adversely affect the luminance signal.

In this frequency conversion process, the horizontal synchronization signal extracted by the horizontal synchronization signal separation circuit 41 in the input signal is supplied to the multiplier circuit 42 to obtain a signal with frequency f LSC, and fs
It is supplied to a frequency converter 44 together with an oscillation signal from a reference oscillator 43 having an oscillation frequency of c. The frequency output from this frequency converter 44 (f t, sc + f s
c) The signal for low-frequency conversion is formed by the signal, and the phase shift circuit 45 is used so that signals interleaved with respect to the horizontal scanning frequency are recorded between adjacent tracks.
The phase is appropriately shifted at the timing according to the horizontal synchronization signal.

The output signal of the frequency converter 40 is, for example, 2,4 MH
It is supplied to the LPF 46 which filters the band below z, and the LP
From the F46, a low frequency converted carrier chrominance signal and a carrier high frequency luminance signal (FC-C) having a spectrum arrangement as shown in FIG.
&YH') is obtained. The above F M -Y L and this F
C-C&YH' is frequency-multiplexed by an adder 47 and then recorded on a magnetic tape 48 by a magnetic head 48.

Next, the reproduction system will be explained.゛The video signal reproduced by the reproduction magnetic head 48 is 2,4 MH
F M -Y L, which is supplied to the HPF 50 that passes the band above z and is arranged on the high frequency side, is separated. On the other hand, FC-C&YH' arranged on the low frequency side is extracted by the LPF 51 which passes the band below 2.4 MHz. The extracted F M -Y t is processed by a known limiter circuit 52. The signal is returned to the original baseband signal by the FM demodulation circuit 53, and is further processed by the LPF 54, which passes a band of 4.2M or less, to obtain YL, which is a baseband signal of 0 to 4.2M or less.

On the other hand, the output signal of the LPF 51 is returned to the original color subcarrier frequency, that is, fsc, by a known ACC circuit 55 and a frequency conversion circuit 56 for returning the signal to the original frequency band.
Then, level correction is performed, and furthermore, the frequency conversion circuit 56 also performs time axis correction. That is, the horizontal synchronization signal is extracted from the reproduced video signal by the horizontal synchronization separation circuit 57,
Using this signal, a well-known AFC circuit 58 generates a signal with a frequency fLSC that includes time axis fluctuations of the horizontal synchronization signal, and a color verse signal separated by a burst gate circuit 59 and a signal generated by a reference oscillator 60 are generated. A phase comparator 61 compares the phase with a reference signal of frequency fSC, and the output of this phase comparator 61 is used as a variable frequency voltage controlled oscillator (VC○).
61 to obtain an oscillation signal including time axis fluctuations with the frequency fSC as the center frequency.

The VCO 61 and the output of the AFC circuit 58 are input to the frequency conversion circuit 62, and the frequency is (f sc + f LSC).
A conversion signal for the frequency conversion circuit 56 is formed. This signal is subjected to a phase shift corresponding to the phase shift circuit 45 of the recording system described above in the phase shift circuit 63, and is returned to the original band and phase from the frequency conversion circuit 56, and the time axis fluctuation is removed. C + YH' is output.

Furthermore, this signal is input to the rhombic filter 64, and crosstalk components from adjacent tracks arranged at frequencies that are integral multiples of fH are removed by the aforementioned phase shift.

YL obtained from the LPF 54 via the spatial filter 65 having a filtering area opposite to that of the spatial filter 35, and C+YH obtained from the comb filter 64 via the spatial filter 66 having the same filtering area as the spatial filter 35. ”
is added in adder 67 and encoded ED again.
Get a TV signal. Needless to say, this signal is further supplied to the receiving side shown in FIG.

Now if the input terminal 34 is not an encoded EDTV signal, for example an NT with a band of O~4,2 MHz.
When an SC signal (hereinafter referred to as a full NTSC signal) is input, in other words, when the input signal does not contain a YH multiplied signal, the recording/reproducing circuit configuration shown in Figure 1 performs signal processing similar to that of a conventional VTR. will be held. Then, with the spectrum arrangement shown in Figure 2 (B), FM-YL and FC
-C is recorded. However, when an encoded HDTV signal is input to the input terminal 34, it is recorded in the spectrum arrangement shown in Figure 2 (A) as described above, and both signals can be recorded and played back with the same VTR provided in this embodiment. Therefore,

As described above, in this embodiment, the encoded EDTV
Full NT with signal transmission line band of 0 to 4,2 MHz
Note that the band is the same as the SC signal band, and since the VTR that performs recording and playback is a transmission system in a broad sense, the recordable band of the VTR is 4.2 MHz, which is greater than the full NTSC signal band. If you have one, such a VTR.
Of course not only the full NTSC signal but also the ED-
We noted that it is also possible to configure a VTR that supports TV signals.

In recent years, due to improvements in electromagnetic conversion characteristics due to the development of metal tapes and metal heads, consumer VTRs that support analog and composite signals, and VTRs that use conventional phyllite lids and iron oxide tapes, can only record bands up to 3 PvI Hz. On the other hand, it has become possible for the above-mentioned VTRs to reproduce data in a frequency band of 4.2 MHz or more.

Therefore, according to this embodiment, recording and playback compatible with encoded HDTV signals can be performed using a mechanism similar to that of a VTR compatible with full NTSC signals, for example, when the recordable band of metal with electromagnetic conversion etc. is 4.2 MHz or more. It can also be made possible. In the above embodiment, YH' is frequency interleaved with y+- in terms of horizontal and vertical scanning frequencies like C (its spectrum arrangement is set), and YH'
and 0, the vertical scanning frequency is frequency interleaved (because the spectrum arrangement is set, Y
The multiplexed Y signal applied to the color process circuit of the chroma signal processing system is similar to the conventional chroma signal processing system without separating H' from C.
Even if H' 10C is input, no major disturbance will occur to YL.

In the above embodiment, the encoded EDTV signal was assumed to have a spectrum arrangement as shown in FIGS. 7 and 8, but for example, the carrier wave μ0 of YH′ was set to 0,
5 f SC, the vertical frequency ν of YH′ and the temporal frequency f are both selected as % of C, and YH
Encoded ED-TV signals in which ' is set at 4, 2 to 6, and 0 MHz can also be recorded and reproduced in the same manner as in the above embodiment. However, at this time, it is necessary to switch the characteristics of each spatial filter.

<Effects of the Invention> As explained above, according to the recording method of the present invention, it has become possible to record a wideband video signal with a simple circuit configuration without significantly expanding the band of the recording signal.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a VTR as an embodiment of the present invention; FIGS. 2(A) and 2(B) are FIG. 1(7) VTR1,
Figure 3 is a diagram showing the configuration of the transmitting section of the EDTV signal, and Figure 4 explains the bands of each component signal of the HDTV signal to be transmitted with the configuration shown in Figure 3. Figure 5 is a diagram showing the frequency allocation of the encoded EDTV signal, Figures 6 (A) and (B) are diagrams showing the characteristics of the spatiotemporal filter in Figure 3, and Figure 7 (A) is a diagram showing the frequency allocation of the encoded EDTV signal. ) to (C) are one-dimensional representations of the spectrum distribution of encoded EDTV signals, and Fig. 8 (A) to
(D) is a three-dimensional representation of the spectrum distribution of the encoded HDTV signal, and Figure 9 is a three-dimensional representation of the encoded HDTV signal.
A diagram showing the configuration of the V signal receiving section. Figure 1O (A)' and (B) are diagrams showing the characteristics of the spatiotemporal filter in Figure 9. Figure 11e (A) and (B) are diagrams showing the characteristics of the spatiotemporal filter in Figure 9. FIG. 2 is a diagram showing the characteristics of the spatial filter in FIG. 1; In the figure, YL is a low-band luminance signal, YH' is a converted high-band luminance signal, C is a carrier color signal, 35 is a spatial filter, 38
is an FM modulator, 40 is a frequency conversion circuit, 47 is an adder,
48 is a magnetic head, and 49 is a magnetic tape.

Claims (1)

[Claims] a low-band luminance signal, a carrier chrominance signal that is frequency interleaved with the low-band luminance signal at a horizontal scanning frequency, and a carrier chrominance signal that is frequency interleaved with the low-band luminance signal at a horizontal scanning frequency and frequency interleaved with the carrier chrominance signal at a vertical scanning frequency. A device for recording a video signal including a high-band luminance signal converted to means for separating the multiplexed signal from the high frequency luminance signal; means for frequency modulating the separated low frequency luminance signal; A video signal recording device comprising means for converting, means for frequency multiplexing the frequency-modulated low-band luminance signal and the frequency-converted signal, and means for recording the frequency-multiplexed signal.