JPS61160802A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the sound recording and reproducing jobs with high fidelity by recording the FM signal of the sound signal to a video signal band. CONSTITUTION:In a stereo recording mode the left sound signal is compressed by a noise reduction circuit 10 like in the case of a video recording mode. Then the compressed signal undergoes an FM treatment through an FM unit 11 with a center frequency of 1.5MHz and is supplied to a recording amplifier 1 via a BPF12. While the right sound signal is set between 4.2-5.4MHz by a video signal processing FM unit 19 and supplied to the amplifier 1 via an HPF20. Then the right and left sound signals are recorded on a tape 3 by a rotary head 2 in the form of FM sound signals. In a reproduction mode the demodulation is performed in a reverse procedure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] This invention relates to a magnetic recording and reproducing device in a 3n+m video tape recorder.

[Prior art and its problems 1] For audio recording in an 8II1m video tape recorder (VTR), a frequency modulation audio recording (hereinafter referred to as FM audio) method using a rotating head is adopted.

FIGS. 4 and 5 show block diagrams of the recording and reproducing system of a conventional 8 mm VTR.

As shown in FIG. 4, the audio signal manual section A of the audio recording system A
The audio signal input to i is 1.5M using a well-known method.
The video signal is frequency modulated at a center frequency of Hz and input to the recording amplifier 1, while the video signal input to the video signal input unit Vi is processed in the same manner by the color signal recording system B and the luminance signal recording system C, and then the video signal is input to the recording amplifier 1. After the audio and video signals input to the recording amplifier 1 are amplified,
It is supplied to a rotating disk 2 and magnetically recorded on a tape 3. FIG. 6 is a spectrum diagram of the output signal of the recording amplifier 1. FIG. 7 shows a track pattern recorded on the tape 3, where 50 is a video and audio trunk recorded on the rotary head 2, 51 and 52 are fixed heads such as a cue head and an audio head (both not shown). ) by cue track and audio track.

When reproducing video and audio tracks recorded on the tape 3, the output of the rotary head 2 is sent to a preamplifier 6 via a changeover switch 5 driven by a head switching pulse generator 4, as shown in FIG. After that, processing is performed using well-known techniques in the audio reproduction system 9-color signal reproduction system E and luminance signal reproduction system F, and the audio signal output section Ao,
Predetermined signals are respectively output to the video signal output section Vo.

As mentioned above, since the 8-city video is recorded using FM audio, it is possible to record and reproduce high-fidelity audio, but the audio recording is in one system, and only monaural recording and reproduction is possible.

JP-A-59-6228, which made stereo recording possible
Publication No. 8 discloses a method of recording a single-carrier audio FM signal obtained by converting a stereo signal of television broadcasting to a low frequency, but it has low deviation and
Due to the signal processing method using a matrix of left and right channels, high-fidelity audio recording and playback could not be expected.

[Objective of the Invention 1] This invention has been made to eliminate the above-mentioned problems, and provides a magnetic recording and reproducing device that enables high-fidelity audio recording and reproduction by adding a simple circuit to a conventional 8n+m VTR. The purpose is to provide.

[Configuration 1 of the Invention The magnetic recording/reproducing device of the present invention is a magnetic recording device that uses a rotary head to superimpose and record a frequency-modulated audio signal, a low-frequency converted video signal, and a frequency-modulated video luminance signal. The apparatus is provided with a modulation means for frequency modulating the input audio signal during recording, and records the signal modulated by the modulation means on the video signal recording band, and when playing back, the signal modulated by the modulation means is recorded on the video signal recording band. The present invention is characterized in that a demodulation means for processing the audio signal is provided.

[Embodiment 1] This invention performs recording and playback using another FM audio system using a luminance signal system in recording and playback, and combines it with recording and playback using FM audio using a conventional audio system to create two systems, that is, stereo recording and playback. is possible.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 shows a block diagram of the recording system, and the same parts as in FIG. 4 are given the same reference numerals, and different parts will be explained.

The video signal input section Vi is connected to a common contact of a switch SW1, one contact V of this switch SWI is connected to a color signal recording system H and a luminance signal recording system I, and the other contact A of this switch SWI is connected to a common contact of a switch SW1. It is connected to the input section of an additional circuit J consisting of a regression circuit 21 and a bias adjustment circuit 22. A switch SW2 is provided between the luminance signal recording system I pre-emphasis circuit 18 and the frequency modulator 19, and the output section of the pre-emphasis 18 is connected to one contact (2) of this switch SW2. The output part of the additional circuit J is connected to the other contact A of this switch SW2, and the common contact of this switch SW2 is connected to the frequency modulator 1.
It is connected to the input section of 9. Further, a switch SW3 is provided between the output section of the color signal recording system H and the recording amplifier 1,
The output section of the color signal recording system H is connected to the common terminal of this switch SW3. One terminal ■ of this switch SW3 is connected to the input section of the recording amplifier 1, and this switch SW3
The other terminal A is an empty terminal.

Next, the operation of the recording system having the above configuration will be explained.

When recording a video signal, the switches SWI to SW3 are switched to contact point (2), and the video signal and monaural audio signal are recorded on the tape 3 by the rotary head 2 in the same way as in the conventional recording system.

On the other hand, when performing stereo recording, the above switch SWl
~SW3 is switched to contact A, and the audio signal of the left channel, for example, is input to the audio signal input section Ai, and the audio signal is processed by the noise reducer circuit 10 in the same way as when recording video in this audio recording system G. It is compressed, frequency-modulated at a center frequency of 1.5 MHz by a frequency modulator 11, and passed through a bandpass filter 12 to a recording amplifier 1.
is input.

A right channel audio signal is input to the video signal input section Vi instead of the video signal, and this signal is input to the additional circuit J via the switch SWI.

The signal is processed by the noise reduction circuit 21 of this additional circuit J and input to the frequency modulator 19 via the bias adjustment circuit 22 and switch SW2. Frequency modulation is carried out in this frequency modulator 19, which is a modulator for video signal processing, and uses a carrier frequency with a synchronization tip of 4.2 MHz and a white tip of 5.4 MHz. Therefore, when the audio signal is modulated by this frequency modulator 19, the frequency band is set between 4.2 MHz and 5.4 MHz as shown in FIG.
When a predetermined bias is set in the bias adjustment circuit 22, the output of the frequency modulator 19 is input to the recording amplifier 1 through a bypass filter 20, and the left channel and right channel of the audio signal input to the recording amplifier 1 are input to the recording amplifier 1. The frequency modulated signals of the channels are superimposed and a frequency modulated audio signal is recorded on the tape 3 by the rotary head 2.

FIG. 3 shows a block diagram of the reproduction system, and parts different from those in FIG. 5 will be explained.

The output part of the bypass filter 40 in the luminance signal reproduction system M is connected to the common contact of the switch SW4, and this switch S
Contact point (3) of W4 is connected to the human power section of the dropout IH delay circuit 41. The output section of the IH delay circuit 41 is connected to the contact point (3) of the switch SW5, and the common contact point of this switch SW5 is connected to the input section of the demodulator 42. The output part of the demodulator 42 is connected to a common contact of a switch SW6, and the contact (2) of this switch SW6 is connected to the input part of a de-enfussis circuit 43. The output section of the luminance signal reproduction system M and the output section of the color signal reproduction system are connected to the contact point (2) of the switch SW7.

Furthermore, a dropout detection circuit 45. Sample and hold circuit 46. An additional circuit N consisting of a low-pass filter 47 and a noise reduction circuit 48 is provided.

Contacts A of the switches SW4 and SW5 are connected to the input part of the dropout detection circuit 45,
The contact A of No. 6 is connected to the input section of the sample and hold circuit 46.

The output of the dropout detection circuit 45 and the output of the head switching pulse generator 4 are respectively connected to separate inputs of the sample and hold circuit 46. Sample hold circuit 4
The output part of 6 is connected to the input part of the low-pass filter 47, and the output part of the low-pass filter 47 is connected to the input part of the noise reduction circuit 48. The output section of this noise reduction circuit 48 is connected to the contact A of the switch SW7, and the common contact of this switch SW7 becomes the video signal output section Vo.

Next, the operation of the reproduction system having the above configuration will be explained.

When reproducing a video signal, the switches SW4 to SW7 are switched to contact ■, and the video and audio modulation signals recorded on the tape are detected by the rotary disk 2, and the audio modulation signal is detected as in the conventional playback system. is the audio signal output section A by the audio signal reproduction system K.

An audio signal is output to the video signal output section Vo, and a predetermined video signal is output to the video signal output section Vo by the color signal reproduction system and luminance signal reproduction system M as the video modulation signal.

On the other hand, when playing back a stereo-recorded tape 3, the switches SW4 to SW7 are switched to contact A, and the modulated signal detected by the rotary head 2 is amplified by the amplifier 6 and then by the bandpass filter 30. Low pass filter 3
6 and a bypass filter 40. The left channel audio modulation signal recorded by the audio signal recording system G in FIG.
0, it is demodulated into a low frequency audio signal by the demodulator 30, and the next sample hold circuit 33 removes the noise caused by the dropout detected by the dropout detection circuit 31 and the head generated by the head switching pulse generator 42. Switching noise is reduced. And low pass filter 3
4, the audio signal is expanded by the noise reduction circuit 35, and the audio signal of the left channel is output to the audio signal output section Ao.

In addition, the right channel audio modulation signal recorded via the additional circuit J and the luminance signal recording system (2) in FIG.
The signal is input to the additional circuit N via 2, undergoes the same signal processing as in the audio signal reproduction system described above, and outputs the right channel audio signal to the video signal output section Vo.

In this way, the audio signal output section Ao and the video signal output section Vo
Since the left and right audio signals are output respectively to the left and right audio signals, stereo recording and playback can be performed.

[Effects of the Invention 1] As detailed above, the magnetic recording and reproducing device of the present invention is capable of high-fidelity stereo recording and playback using frequency modulation in addition to conventional video recording and playback by providing an additional circuit to a conventional 8mm VTR. It becomes possible. Furthermore, if a recording function using PCM (Pulse Code Modulation), which is a separate specification of the 8+am VTR, is added, it becomes a 2-channel stereo recording/playback machine or a 4-channel recording/playback machine.

[Brief Description of the Drawings] Figures 1 and 3 are block diagrams of a recording system and a playback system showing a first embodiment of the present invention, and Figure 2 shows two systems of audio signals using the recording system of Figure 1. Signal spectrum diagram when recorded,
Figures 4 and 5 are block diagrams showing conventional recording and playback, Figure 6 is a spectrum diagram of video and audio signals recorded using the recording system shown in Figure 4, and Figure 7 is recorded on tape. FIG. DESCRIPTION OF SYMBOLS 1... Recording amplifier, 2... Rotating head, 3... Tape, 4... Head switching pulse generator, 5... Changeover switch, 6... Preamplifier, 45... Dropout detection Circuit, 46... Sample hold circuit, 47
...Low pass filter, 48...Noise reduction 3
Switch, G... Audio signal recording system, H... Color signal recording system, ■... Luminance signal recording system, K... Audio signal reproducing system, L... - Color signal reproduction system, M...luminance signal reproduction system, J, N...additional circuit.

Claims (1)

[Claims] (1) In a magnetic recording device that uses a rotary head to record a frequency-modulated audio signal, a low frequency-converted video signal, and a frequency-modulated video luminance signal in a superimposed manner, an input audio signal is used during recording. A modulating means for frequency modulating the signal is provided, the signal modulated by the modulating means is recorded in a video signal recording band, and a demodulating means is provided for processing the audio signal recorded in the video signal recording band during playback. A magnetic recording/reproducing device characterized by: