JPS62176392A - Magnetic picture recording system - Google Patents

Abstract

PURPOSE:To record a wide band luminance signal by a tape head system narrow in recording and reproducing signal band by superimposing a low frequency chrominance signal on one of the luminance signals divided into two channels to be a narrow band and a high frequency chrominance signal on the other and using two heads to record. CONSTITUTION:R, G, B signals are converted into a Y signal and both of CW and CN signals in a matrix circuit 5 and the Y signal is divided into a Y1 signal and a Y2 signal by a two division circuit 6 through a time base extension. The chrominance signals CW and CN are converted into a linear sequential signal CW/CN by a linear sequential converter 7, the lower frequency chrominance signal CL is formed by an LPF 10, guided to an additing circuit 13 through an FM modulator 12 and superimposed on the FM modulated Y1 signal by an FM modulator 8 to obtain a signal a. The signal CL is subtracted from the signal CW/CN by a subtracter 11 to have the high frequency chrominance signal Ch, it is synthesized with the Y2 signal by a Ch synthesizer 9, modulated by an FM modulator 14, and an output of a sound FM modulator 15 is multiplexed by an adder to obtain a signal b. The signals a, b are supplied to heads 21-24 through a switch 19 and recorded on a tape 25 by using two tracks.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording method suitable for recording wideband color signals, and in particular to magnetic recording when recording high-definition television signals on a VTR. Method % Formula % [Prior Art] Conventionally, in this type of VTR, the luminance signal Y1 . Y2 and two systems of color signals Cw
, CH, and then FM-modulated the recording signals on the tape using four heads.

However, there was a gap in the recorded signal of each channel where the spectrum of each line frequency was missing. Also, FM
There is also a space in the modulated wave where there is no signal spectrum on the lower side of the lower sideband spectrum.
Conventionally, these spectrum spaces were not used effectively, resulting in waste.

r, Q [18A (alternative 5l ← Chishi + Su 4 11%
As mentioned above, the recording signals of conventional high-quality VTRs have gaps in the spectrum distribution, which have not been utilized effectively.

Therefore, the purpose of the present invention is to basically divide the luminance signal into two systems by time axis extension in order to record a wideband luminance signal using a tape head system with a relatively small relative speed and narrow recording/playback signal band. The objective is to add a monochromatic code recording function to the system of recording on tape using two heads.

[Means for Solving the Problems] In the magnetic recording system according to the present invention, one of the luminance signals divided into two channels and made into a narrow band is FM-modulated, and
A first recording signal in which an FM modulated wave of a low frequency color signal divided by an fJIH filter is superimposed on the lower end of the spectrum of the modulated wave, and a high frequency color signal is added to the other of the luminance signals. Two systems of signals are magnetically recorded using two heads, consisting of a baseband band superimposed by carrier wave suppression AM modulation using a subcarrier so as to have a frequency interleaved relationship, and a second recording signal which is entirely FM modulated. It is recorded on a medium.

[Embodiment] FIG. 1 is a block diagram showing an entire embodiment of the present invention. This embodiment includes luminance signal waiting axis expansion division, color signal low frequency FM superimposition, and high frequency baseband multiplexing FM? This is a channel recording type signal processing circuit.

Here, l shown in FIG. 1(A) is an R signal, 2 is a G signal,
3 is a B signal, 5 is a matrix circuit, 6 is a 2-divider circuit, 7
8 is a line sequential converter, 8 is an FM modulator, 9 is an ah (high frequency color signal) synthesizer, 10A and IOB are LPFC low-pass filters), 11 is a subtracter, 12 is an FM modulator, 13 is an addition circuit, 14 is an FM modulator, 15 is an audio FM modulator, 18 is an adder, and 17.18 is a recording amplifier.

Further, as shown in FIG. 1(B), 111 is a sweep 2,000, 2° is a head drum, 21 to 24 are heads, 25 is a tape, and 28 to 29 are head amplifiers.

Further, in FIG. 1(C), 30 to 33 are RF equalizers, 34.35 is an RF switcher, 38.37 is a frequency separation circuit, 38 to 40 are FM demodulators, 41 is an audio FM demodulator, and 42 is Ch (high range color signal) molecule 111m circuit, 43
．． 44 is a TBc (time base collector), 45 is an adder, 46 is a TBC/time axis compression synthesis circuit, 47 is a line sequential inverse conversion circuit, 4th is an inverse matrix circuit, 49 is an R signal (
Band 27MH2).

50 is a G signal (bandwidth 27 MHz), 51 is a B signal (band 27 MHz), and 52 is an audio signal.

FIGS. 2(A) and 2(B) are diagrams showing the frequency spectra of recording channels (■) and (2) in this embodiment.

Next, the operation of this embodiment will be explained with reference to FIG. 1 and FIGS. 2(A) and (B) mentioned above.

Output from a high-definition television camera (each band is 30M)
By combining the matrix circuit 5 and a low-pass filter (not shown), the R, G, B signals 1 to 3), which have a certain frequency of Hz, are converted into a Y signal with a band of 27 MHz, a Cw with a band of 7 MHz,
CH and both signals.

This Y signal is divided into two by a time axis expansion circuit 6.
It is divided into two systems of 11 Y + Y2 signals whose band is 1/2 of the Y signal. Among these signals, Y11 are FM modulated by the FM modulator 8.

On the other hand, the color signals Cw and CN are introduced into the line sequential converter 7.
It is converted into a systematic line sequential signal (Cw/CN), and then a low-pass chrominance signal C is formed by L P F 10 with a cutoff frequency of 2 MHz. This signal C is subjected to FM modulation by an FM modulator 12 , guided to an adder circuit 13 , and superimposed on the output of the FM modulator 8 . This addition output signal is FMYl + F
MCL, and its spectrum is shown in Figure 2 (A).
Shown below.

In addition, by subtracting the signal C from the signal (Cw/CN) using the subtractor 11, a high-frequency color signal channel having a spectrum of 2 to 7 MHz is obtained, which is introduced into the channel synthesizer 9 and synthesized with Y22. and forms a signal (Y2+ch).

At this time, if the spread of the Y22 spectrum is large and there is interference, L P F IQB is inserted as appropriate.

The signal obtained from the channel synthesizer 9 is introduced into the FM modulator 14 to perform FM modulation.Here, the output signal of the FM modulator 14 is expressed as FM (Y2+Ch), are multiplexed by an adder 18. The spectrum of the signal (2) thus obtained is shown in FIG. 2(B). Here, the output of the audio FM modulator 15 is expressed as FM (audio).

The above-mentioned signals ■ and ■ are amplified by recording amplifiers 17 and 18,
Head drum (
4 heads 21 arranged on the rotation speed 30 rps) 20
~24. Then, the signal for 1 field is 2
Record on tape 25 using a wooden track.

Also, by turning switch 19 to the FB side, 21~
The head output of 24 is amplified by head amplifiers 26 to 29, and further equalized by RF equalizers 30 to 33 to be suitable for FM demodulation.
After the signal is made into a continuous signal by 1 frequency separation circuit 38.
37, the original FM Y, , FM CL and FM (
Y2+Ch) and FM (audio) signals,
Each is demodulated by an FM demodulator 38, 33, 40.

Thus, the baseband signals Yt +CL and (Y2+C
h) is obtained.

(Y2+Ch) signal is introduced into the channel separation circuit 42,
Ch (high frequency color signal) is detected and separated from the two signals. Thereafter, the time axis is stabilized via the TBC 43, the time axis is stabilized using the same <TBC 44, and the frequencies of the signal C and the signal C are superimposed in the adder 45. As a result, a line-sequential color signal (Cw/CN) with a band of 7 MHz is introduced into the line-sequential inverse conversion circuit 47.

The output Y1 signal of the FM demodulator 38 and one output Y2 signal of the channel separation circuit 44 are respectively guided to the TBC/time axis compression synthesis circuit 46 to obtain a Y signal with a band of 27 MHz. The Y signal is outputted from the line sequential inverse conversion circuit 47 as Cw and C.
N to the inverse matrix circuit 48, band 27MH
z R, G, and B signals 49 to 51 are output.

Further, one output of the one-frequency separation circuit 37 is guided to an audio FM demodulator 41 to output an audio signal 52.

FIGS. 3(A) to 3(C) are diagrams showing the configuration and characteristics of the channel (high-frequency color signal) synthesis circuit on the Kinomio side.

In this figure, 55 is a color subcarrier generator, 5B is a carrier suppression AM modulator, and 57 is an adder.

As shown in FIG. 3(A), a circuit shown in FIG. 3(C) is configured to configure a channel signal spectrum having a frequency interleaved relationship with the Y2 signal. First, the color subcarrier generator 55 outputs an fsc of about 8 MHz, where fsc: color subcarrier frequency fh: horizontal synchronization frequency n: an integer. Then, the channel input signal (2 to 7 MHz) is modulated using the carrier suppression AM modulator 5B, and then Y2
The human input signal and its modulated output are multiplexed by an adder 57.

In addition, when selecting the color subcarrier frequency fsc, C
It is preferable to set the h lower side wave as high as possible so that it does not reach the low range where the amplitude of the Y2 signal spectrum is large. On the other hand, in order to avoid being disturbed by triangular noise after FM demodulation, it is preferable to consider fsc to be as low as possible.

In addition, when selecting the cutoff frequency of the LPF IOA shown in Fig. 1(A), it is necessary to select the Y2
It is preferable to consider conditions that do not interfere with the signal spectrum.

Also, as a second embodiment to which the present invention is applied.

It is also possible to obtain the signal of the recording channel (2) described above by processing it in the same manner as that of the recording channel. In other words, the high-frequency color signal channel is taken out as a 2-7 MHz signal or converted into a 0-5 MHz signal by frequency shifting), first subjected to FM modulation, and then superimposed with the FM modulated wave of the Y2 signal. It is also possible.

Furthermore, as a third embodiment, first, the low frequency color signal C is subjected to subcarrier suppression AM modulation to produce Y.

It is also possible to baseband multiplex the signal and then perform FM modulation to obtain the signal of the recording channel.

[Effects of the Invention] By implementing the present invention, the following special effects can be obtained.

(a) A color signal recording function can be added to the conventional two-channel luminance signal recording method without increasing the required band of the tape head system.

(b) FM modulates the low frequency component of the color signal at the baseband,
By recording in a band with a high CN ratio (low frequency range) of the tape head system, the reproduced SN ratio can be improved. Furthermore, by recording the high-frequency components of the color signal without frequency shifting, it is possible to avoid distortion caused by the frequency shift circuit.

(c) The relative speed is relatively low (15 to 20 m/s), the number of heads is as small as 4, and the tape is wound around the rotating drum using a mechanism system that is easy to configure with a corner of 180'.
MHz broadband color signals can be recorded.

[Brief explanation of drawings]

1 (A) to (C) are signal processing block diagrams of a luminance signal time axis expansion division, chrominance signal low frequency FM superimposition, high frequency baseband multiplexing FM 2 channel recording method, which is an embodiment of the present invention. Figures (A) and (B) show recording channels 0. Diagram showing the frequency spectrum of ■. FIGS. 3A to 3C are diagrams showing the configuration and characteristics of the high-frequency color signal synthesis circuit. 1...R signal, 2...G signal, 3...B signal, 5...matrix circuit, 6...2 division circuit, 7...line sequential converter, 8...FM Modulator, 9...ch (high frequency color signal) synthesizer, 10A, IOB
... LPF (low pass filter), 11 ... Subtractor, 12 ... FM modulator, 13 ... Addition circuit, 14 ... FM modulator, 15 ... Audio FM modulator, 1B. ...Adder, 17.18...Recording amplifier, 19...Switch. 20... Head drum, 21-24... Head, 25... Tape, 2B-29... Head amplifier, 30-33... RF equalizer, 34.35... RF switcher, 38.37...Frequency separation circuit, 38-40...FM demodulator, 41...Audio FM demodulator, 42...ch (high frequency color signal) separation circuit, 43.44
... TBC (time base collector), 45... Adder, 46... TBC◆Time axis compression synthesis circuit, 47... Line sequential inverse conversion circuit, 48... Inverse matrix circuit, 49.R signal (bandwidth 27MHz), 50...G signal (bandwidth 27MH2), 51-B signal (
Bandwidth 27M) Iz), 52...Audio signal, 55...Color subcarrier generator, 5B...Carrier suppression AM modulator, 57...Adder/Patent applicant Japan Broadcasting Association fee Attorney Patent attorney Yoshi Tani --he e ○ O■ e OQ ri

Claims (1)

[Claims] 1) FM modulate one of the luminance signals that have been divided into two channels to narrow the band, and further divide the spectrum of the modulated wave to the lower end of the lower end using a filter. A first recording signal in which an FM modulated wave of a color signal is frequency-superimposed, and a high-frequency chrominance signal is superimposed on the other of the luminance signals in a baseband band by carrier suppression AM modulation using a subcarrier so as to have a frequency interleaved relationship, A magnetic recording system characterized in that two systems of signals, each consisting of a second recording signal whose entirety is FM modulated, are recorded on a magnetic recording medium using two heads.