JPH02214004A - Signal recording system for video tape recorder - Google Patents

Abstract

PURPOSE:To perform the recording of two or more systems of video and sound signals simultaneously by performing the multiplex recording of the video signal converted to an FM signal, a four-phase differential phase modulated video signal, and a frequency modulated sound signal on a magnetic tape by individual rotary magnetic head, respectively. CONSTITUTION:For example, two systems of signal input terminals 2 and 3 are provided. And the video signal from the input terminal 2 of a first system is recorded 6 after applying a conversion processing to the FM signal, and also, the sound signal from the terminal 2 is recorded by fixed magnetic heads 10a and 10b. Meanwhile, the video signal from the signal input terminal 3 of a second system is A/D-converted 11, and a digital signal on which a digital signal processing 12 is applied is four-phase differential phase QPSK-modulated 14, and also, the sound signal from the terminal 3 is frequency modulated 18. Thereby, the video signal converted to the FM signal, the four-phase differential phase modulated sound signal, and the frequency modulated voice signal can be multiplex recorded on the magnetic tape 7 by each of the rotary magnetic heads 6, 16, and 20, individually.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a signal recording method in a video tape recorder.

<Prior Art> Some home video tape recorders are equipped with signal input terminals for multiple systems, but it is difficult to record signals from two systems at the same time, for example, signals from television broadcasts and signals from other video tape recorders. I couldn't do that. Therefore, there is a need for a video tape recorder that can simultaneously perform efficient recording.

<Problems to be solved by the invention> The present invention has been made in view of the above points, and has two problems.
To simultaneously record video and audio signals of two systems. The purpose is to

Means for Solving the Problems> In order to achieve the above objects, the present invention provides at least six
It has two signal input terminals, converts the video signal from the first system signal input terminal into an FM signal and records it, and also converts the audio signal from the first system signal input terminal to a fixed magnetic head. A signal recording method in a video tape recorder that records video signals by converting a video signal from a signal input terminal of a second system into a digital signal and subjecting it to four-phase differential phase modulation. F
M-modulated video signal converted into the FM signal;
The differential phase modulated video signal and the FM modulated audio signal are multiplexed onto a magnetic tape by separate rotating magnetic heads.

<Operation> According to the above configuration, the video signal and audio signal of the first system are processed in the same way as in the case of a conventional video tape recorder that is not high-fidelity, and the video signal of the second system is
The audio signal of the second system is subjected to four-phase differential phase modulation and is processed as high-fidelity audio, and the video signal of the first system, the video signal of the second system, and the audio signal of the second system are each individually processed. Since multiplex recording is performed in three layers on the magnetic tape using a rotating magnetic head, it is possible to simultaneously record two systems of video and audio signals.

<Examples> Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of a video tape recorder according to an embodiment of the present invention.

The video tape recorder 1 of this embodiment is equipped with two systems of signal input terminals 2.3.

The video signal from the video signal input terminal 2a of the first system is
The signal is applied to the video signal processing circuit 4. In this video signal processing circuit 4, the color signal is 629kHz±500kHz.
The luminance signal is FM modulated with a 5.4 MHz carrier, and both signals are superimposed and given to the recording amplifier 5, and further recorded on the magnetic tape 7 by the rotating magnetic head 6 as described later. be done. In other words, the conventional 5
- Signal processing similar to the video signal in a VH8 video tape recorder is performed.

The audio signals of each channel from the audio signal input terminals 2b and 2c of the first system are recorded on the magnetic tape 7 by fixed magnetic heads lOa and 10b via a linear audio circuit 8 and a recording amplifier 9. That is, it is similar to normal audio recording in a conventional video tape recorder.

In the signal recording system in the video tape recorder of this embodiment, in order to simultaneously record two systems of signals, the second
The video and audio signals of the system are recorded as follows.

The video signal from the video signal input terminal 3a of the second system is
The A/D conversion circuit 1 samples the signal at 14.3 MF (z) and converts it into an 8-bit digital signal. This digital signal is given to the digital signal processing circuit 12.

In this digital signal processing circuit 12, an error correction signal is added and interleaved using the RAM 13 as a working area, and the four-phase differential phase modulation circuit 14 (
Output to QPSKII: network circuit). This QPS
K'! In the R1II circuit 14, a video signal subjected to four-phase differential phase modulation using a 2.5 MHz carrier is amplified by a recording amplifier 15 and recorded by a rotating magnetic head 16 as described below.

The audio signals of each channel from the audio signal input terminals 3b and 3c of the second system are given to a noise reduction circuit 17 for reducing noise, and then to an FM modulation circuit! 8 for each channel.

F'M with 3MHz and 1.7MHz carriers respectively
The signal is modulated, further amplified by a recording amplifier 19, and then recorded on the magnetic tape 7 by a rotating magnetic head 20. That is, it is similar to high-fidelity audio recording in a conventional video tape recorder.

Among the signals subjected to the above processing, the first system of audio signals is recorded on the magnetic tape 7 by the fixed magnetic heads 10a and 10b, and the other signals are recorded, for example, on the magnetic tape 7.
Separate rotating magnetic heads 6.16 in the arrangement shown in FIG.
．． 20, respectively. That is, the video signal of the first system is recorded by a pair of rotating magnetic heads 6, and the video signal and audio signal of the second system are recorded by each pair of rotating magnetic heads forming an angle of 120 degrees with the rotating magnetic head 6. are recorded by heads 16 and 20, respectively.

Recording by this rotating magnetic head 6.16.20 is FM
The audio signal, the four-phase differential phase modulated video signal, and the video signal converted to the FM signal are multiplexed in three layers on the magnetic tape 7 in this order. The recording depth is F
The video signal converted into the M audio signal and the FM signal is the same as in the case of a conventional high-fidelity video tape recorder, and the depth of the video signal subjected to 4-phase differential phase modulation is approximately halfway between the above two signals. It is considered to be deep.

FIG. 3 shows the frequency allocation of each signal recorded by the rotating magnetic heads 6, 16, and 20, and FIG. 3(A) shows the first system of video signals recorded by the rotating magnetic head 6. , FIG. 3(B) shows a second system of video signals recorded by the rotating magnetic head 16, and FIG. 3(C) shows a second system of audio signals recorded by the rotating magnetic head 20. There is.

As shown in Fig. 3, the FM-modulated luminance signal has a range of 5.4 to 7.0 from the synchronization tip to the white beak.
MHz. The four-phase differential phase modulated video signal has a band of 1.3 MHz centered on 2.5 MHz.

As described above, it is possible to simultaneously record two systems of video and audio signals on the magnetic tape 7.

Regarding the video signal of the second system, it is possible to record either a still image or a moving image by selecting the sampling frequency and the number of quantization bits in the A/D conversion circuit 11 or by compressing the band after A/D conversion. is also possible.

FIG. 4 is a block diagram for reproducing signals recorded in this manner.

The signal reproduced by the rotating magnetic hept 6 is amplified by a reproduction preamplifier 21 and provided to a video signal processing circuit 22 . In this video signal processing circuit 22, the color signal is
The brightness signal is returned to 3.58MHz±500kHz,
FM demodulated. The video signal reproduced by this video signal processing circuit 22 is output from the first system video signal output terminal 23a.

The signals reproduced by the fixed magnetic heads 10a and 10b are
It is amplified by the reproduction preamplifier 24 and converted into an audio signal by the linear audio circuit 25, and then sent to the audio signal output terminal 23b of the first system.
, 23c, respectively.

The signal reproduced by the rotating magnetic head 16 is amplified by a reproduction preamplifier 26, and then sent to a four-phase differential phase demodulation circuit 27 (
(QPSK demodulation circuit) and provided to the digital signal processing circuit 28, and this digital signal processing circuit 28 converts the RA
Deinterleaving and error correction are performed using M29 as a working area, and the signal is further converted into an analog signal by the D/A conversion circuit 30 and output from the video signal output terminal 31a of the second system.

The signal reproduced by the rotating magnetic head 20 is amplified by a reproduction preamplifier 32, demodulated by an FM demodulation circuit 33, and further passed through a noise reduction circuit 34 and output from the audio signal output terminals 3 lb and 3 IC of the second system, respectively. Output.

<Effects of the Invention> As described above, according to the present invention, in a video tape recorder having two systems of signal input terminals, the video signal and audio signal of the first system are the same as those of a conventional non-hi-fi video tape recorder. Process the signal in the same way as
The video signal of the system is subjected to 4-phase differential phase modulation, the audio signal of the second system is processed in the same way as high-fidelity audio, and the video signal of the first system, the video signal of the second system, and the second system are
Since the audio signals of the following systems are multiplexed in three layers on the magnetic tape using separate rotating magnetic spatulas,
It is possible to simultaneously record two systems of video signals and audio signals.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a recording system of a video tape recorder according to an embodiment of the present invention, FIG. 2 is a diagram showing the arrangement of a rotating magnetic head, FIG. 3 is a diagram showing the frequency distribution of recording signals, and FIG. This figure is a block diagram of the reproduction system of the video tape recorder shown in FIG. 1. 2.3...Signal input terminal, 6,16.20...Rotating magnetic head, 10a, 10b...Fixed magnetic head,
7...Magnetic tape, 14...4-phase differential phase modulation circuit.

Claims (1)

[Claims] (1) It has at least two systems of signal input terminals, and the video signal from the first system of signal input terminals is converted into an FM signal and recorded, and the audio signal from the first system of signal input terminals is recorded. This is a signal recording method for a video tape recorder that records with a fixed magnetic head, the video signal from the signal input terminal of the second system is converted into a digital signal and subjected to four-phase differential phase modulation, and the video signal of the second system is The audio signal from the signal input terminal is FM modulated, and the video signal converted into the FM signal, the video signal subjected to the four-phase differential phase modulation, and the audio signal subjected to the FM modulation are magnetically modulated by separate rotating magnetic heads. A signal recording method in a video tape recorder characterized by multiplex recording on tape.