JPS60231901A - Magnetic video recording and reproducing device - Google Patents

Abstract

PURPOSE:To utilize the whole recording band of a magnetic tape effectively by recording a frequency-modulated sound signal in a frequency band for luminance signal recording when the recording of a video signal is unnecessary. CONSTITUTION:A change-over switch 13 is arranged to connect any one of an adder 26 for adding the outputs of frequency modulation circuits 25l, 25r and a video input circuit 3v selectively to adders 11a, 11b, and when a video signal is not recorded, the switch 13 is turned so that the adder 26 is connected to tha adders 11a, 11b. In this case, an external sound signal having sound carriers f'L, f'R as its frequency components is supplied to the adders 11a, 11b instead of the luminance signal and recorded in the magnetic tape 2 through rotary magnetic heads 9a, 9b. When only a sound signal is to be recorded in the magnetic tape 2, the recording band of the external sound signal can be expanded sufficiently widely, so that sound recording of two channels or more can be sufficiently attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a magnetic recording and reproducing device with further improved audio recording characteristics.

[Conventional technology]

In order to make the audio recorded on the magnetic tape used for video recording high-fidelity, a so-called frequency multiplex recording method is used to multiplex record a frequency modulated audio signal in a frequency band between the frequency modulated luminance signal and the low frequency converted chromaticity signal. A magnetic recording/playback device has been proposed. When recording two-channel audio using frequency modulation, two types of audio carrier waves are originally required. However, if the video track uses the β method for recording multiple signals using the guard panless azimuth recording method, The frequency of the audio carrier is shifted by 150 kHz in adjacent tracks to avoid interference with
8 MHz and 1.68 MHz t7) the track on which the audio carrier is recorded and 1.53 MHz and 1.83 MHz
The tracks on which the audio carrier waves of z are recorded are arranged alternately.

[Problem that the invention seeks to solve]

The conventional magnetic recording/playback device described above records four types of audio signals with different carrier frequencies in a limited frequency band between the luminance signal and the chromaticity signal, so the frequency transition width of the audio signal for each channel is also limited. Furthermore, unlike luminance signals, which can be recorded using the saturation magnetic recording method, audio recording is performed using the AC bias recording method, which has problems such as the difficulty in obtaining open hearth gH wavenumber characteristics and a high 8N ratio. .

Further, when video recording is not performed, there is a problem that even though the recording band of the 111 signal is vacant, this recording band cannot be used effectively.

[Means for solving problems]

This invention solves the above problems, and uses a predetermined frequency band provided between the frequency-modulated luminance signal and the low-frequency converted chromaticity signal to multiplex the frequency-modulated audio signal. , a magnetic recording and reproducing apparatus configured to record multiplexed signals on a magnetic tape, comprising: a frequency modulation circuit that frequency-modulates an audio signal using an audio carrier wave having a frequency within a frequency band of the frequency-modulated luminance signal; In the case where the luminance signal is not recorded on the tape, the present invention is characterized in that an audio recording means is provided for recording the output of the frequency modulation circuit on the magnetic tape using the frequency band of the luminance signal.

[Effect]

According to the present invention, when it is not necessary to record a video signal, a frequency modulated audio signal can be recorded in a frequency band for recording a luminance signal, and the recording band of a magnetic tape can be effectively utilized over the entire area.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a schematic circuit diagram showing an embodiment of the magnetic recording/reproducing apparatus of the present invention, and a diagram showing frequency spectra of each part for explaining the recording method, respectively.

In FIG. 1, a magnetic recording/reproducing device 1 employs a heterogain audio frequency modulation method that performs modulation and demodulation at a frequency sufficiently higher than the frequency of the frequency modulated audio signal actually recorded on a magnetic tape 2. For this reason, a signal processing process such as frequency conversion of audio signals, which is not found in conventional high-fidelity magnetic recording and reproducing devices, is employed. That is, the audio carrier wave used for frequency modulation of the audio signal is a high frequency of about 5 MHz, which is higher than the carrier frequency of the luminance signal, and the frequency modulated audio signals of the left and right channels are added together and then frequency modulated. In addition to recording as an S wave, during reproduction, the audio signal read from the magnetic tape 2 is converted into a high frequency band, and then the individual signal is converted into a band f wave and demodulated.

First, regarding the recording system, the left and right audio signals are processed by the audio input circuit 3s to emphasize high frequencies, limit excessive input, etc.
Frequency f'1 in frequency modulation circuits 41 and 4r, respectively.
．． (* 5. I MHz) and fH (medium 5.4 MHz
z) is frequency-modulated and immediately added to the adder 5.
The signals are added at , and supplied to the following frequency converters 6a and 5b as a signal having frequency components shown in FIG. 2(5).

The frequency converters 6a and 6b each have an oscillation frequency of fP.
Frequency conversion is performed using pilot signals supplied from different oscillators 7a and 7b such as oscillators 7a and 7b. frequency fP
A relationship of f −f =150 kHz is maintained between S and f8, and this relationship can be realized with extremely high precision by using a crystal oscillator or the like.

The frequency is converted by the frequency converters 6a and 6i: +, and the second
The left and right channel audio signals SB and Sc having the frequency components shown in FIGS.

8b, the frequency components shown in FIG. 2 (to) become fLA (-"L 'P) and 'RA (= "
R-! The signal SD of p) and the frequency components shown in Fig. 2) are fLB (= f'j - f8) and 'RB (= "R").
S ) is output as f wave as signal SE. However, the subscript A of f corresponds to the rotating magnetic head 9a, and the subscript B corresponds to the rotating magnetic head 9b. Further, the subscript R corresponds to the left channel, and the subscript R corresponds to the right channel. In this way, the audio signal conforming to the β high-fidelity standard is sent to the amplifier circuits 10a, 10b and the adder 1 for adding the video signal.
1a, llb, and recording amplifier circuits 12a, 12b,
The signals are supplied to rotating magnetic heads 9a and 9b, respectively, and recorded on magnetic tape 2.

Note that a video input circuit 3v is connected to the adders 11a and llb via a changeover switch 13t, which will be described later, and supplies a frequency modulated luminance signal Y and a low frequency converted chromaticity signal C during recording. will be carried out.

Next, regarding the reproduction system, there is a rotating magnetic head 9a.

The audio signal read from the magnetic tape 2 by 9b is amplified by the reproduction amplifier circuits 14a and 14b, and then the frequency component is
The signals SD and frequency components of LA and 'RA are 'LB and 'RB.
The signal SF, is converted into an f-wave. Continuing, oscillators 7a, 7
Pilot signals of frequencies fP and f8 are supplied from frequency converters 16at and 16b, respectively, and the frequencies are converted by frequency converters 16at and 16b, and the signals are supplied to amplifier circuits 18a and 18b via changeover switches 17a and 17bi, which will be described later. Amplifier circuit 18a.

The audio signal that has passed through 18b is sent to the sound range wide wave circuit 19, 20°2.
At 1.22, the switch 231, which is switched by the head switching pulse, connects the same frequency components as the frequency modulated audio signal during recording, that is, f'L and f'8, to the P wave.
The signal is supplied to the audio output circuit 24 for each left and right channel via 23r. The audio output circuit 24 is located on the side of FIG.
The frequency modulated audio signal 5H2SI of the left and right channels having the frequency components shown in I) is demodulated after amplitude limiting, and is output after being subjected to dropout compensation and the like.

In this way, recording and reproduction using the heterodyne audio frequency modulation method is performed by the low-frequency P-wave circuit 8a of the recording system.

8b and reproduction system band 85 wave circuit 19, 20, 21゜2
Since the F= condition in 2 is relaxed compared to the conventional β-no-ify method, it is possible to use a broadband and inexpensive filter, and furthermore, the difference in group delay characteristics depending on the filter used can be reduced. Since almost no switching noise occurs, there are advantages such as the ability to effectively suppress the occurrence of switching noise at the joints between tracks.

Here, a superimposed feature of the magnetic recording and reproducing apparatus 1, which is that it can record and reproduce high quality sound when only audio is recorded, will be explained.

As already mentioned, when recording audio signals according to the β Hi-Fi standard, the frequency and wave number modulated audio signals SD and SE are recorded in a frequency band intermediate between the frequency modulated luminance signal Y and the low frequency converted chromaticity signal C. When only audio is recorded on the magnetic tape 2 without recording video, the blank luminance signal recording band can be used for recording external audio signals.

That is, the magnetic recording and reproducing apparatus 1 can record external audio signals that the user wants to record from a sound source such as a record player or a compact disc player on both left and right channels, separately from the frequency modulation circuits 41 and 4r. Thus, a pair of frequency modulation circuits 251.degree. 25r, which constitute the main part of this invention, are connected to the audio input circuit 3S.

In this embodiment, these frequency modulation circuits 251.25r are frequency modulation circuits 41 and 4 whose subscripts correspond to each other.
The audio carrier wave (frequency f′L, . r) is the same as r.

tW > and thus each output is within the frequency band of the frequency modulated luminance signal. Further, the output of the frequency modulation circuit 251.25r is output from the adder 26.
After the addition, the signals are supplied to the changeover switch 13. In addition, in the case of this embodiment, the frequency modulation circuits 251 and 25
r, the adder 26, the changeover switch 13, and the like constitute external audio recording means.

By the way, in the recording system, the video input circuit 3v and the adder 1
A changeover switch 13 provided between 1a and llb switches either the adder 26 that adds the outputs of the frequency modulation circuits 251 and 25r and the video input circuit 3v to the adder 1.
This is provided to selectively connect to 1a and llb.If video recording is not performed, adder 26 and lla
, 11b are connected to each other. Therefore, in that case, an external audio signal having frequency components f'I and tW is supplied to the adder 11a and 1lbK in place of the luminance signal, and is recorded on the magnetic tape 2 via the rotating magnetic heads 9a and 9b. It turns out.

Also, a frequency converter 16a in the reproduction system.

The changeover switches 17a and 17b provided between the reproduction amplifier circuit 16b and the amplifier circuits 18a and 18b are the regenerative amplifier circuit 14a.
, 14b and the frequency converters 16a, 16b to the amplifier circuits 18a, 18b, and the changeover switch 13 is switched to the adder 26 side). If an external audio signal is recorded instead, the regeneration amplifier circuits 14a, 14b and the amplifier circuit 18a.

18b is connected. In that case, f
An external audio signal having frequency components '1 and f'R is directly supplied from the magnetic tape 2 to the amplifier circuits 18a, 18b via the reproduction amplifier circuits 14a, 14b.

By the way, when a frequency-modulated external audio signal using a high-frequency audio carrier wave instead of a luminance signal is directly recorded on the magnetic tape 2, the signal is recorded using a shorter wavelength compared to the β-hi-fi standard audio signal. There is little crosstalk between adjacent tracks, and it is closer to saturation magnetic recording than AC bias recording, so the signal reproduction level is high and the frequency transition width can be wide, resulting in flat frequency characteristics and high SN.
The ratio is obtained.

Furthermore, even when performing high-frequency recording of such external audio signals, the changeover switch 17a.

When the 17b is switched to the frequency converter 16a, 16b side for reproduction, it is possible to reproduce the audio signal of the β-hi-fi standard, so it is possible to provide compatibility with the conventional β-hi-fi magnetic recording device. I can do it.

As described above, according to the magnetic recording and reproducing apparatus 1, when recording only an audio signal without recording a luminance signal on the magnetic tape 2, frequency modulation is performed using an audio carrier wave having a frequency within the frequency band of the luminance signal. Since the external audio signal is recorded on the magnetic tape 2 using the frequency band of the luminance signal, the recording band of the external audio signal can be made sufficiently wide, which allows audio recording of two or more channels. Therefore, it can be used as a multi-channel audio deck, in which case the sound quality will be less crosstalk between adjacent tracks due to the short wavelength recording, and it may also be possible to use less saturation magnetism than AC bias recording. Since it is close to recording, the signal reproduction level is high and the frequency transition width can be wide, so that flat frequency characteristics and a high SN ratio can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, when recording only an audio signal without recording a luminance signal on a magnetic tape,
Since the audio signal is frequency-modulated using an audio carrier wave with a frequency within the frequency band of the brightness signal and is recorded on the magnetic tape using the frequency band of the brightness signal, the recording band of the audio signal is sufficiently wide. This allows 2
It is easily possible to record audio for more than one channel, so it can be used as a multi-channel audio deck. Since bias recording is close to saturation magnetic recording, the signal reproduction level is high and the frequency transition width can be widened, resulting in excellent effects such as flat frequency characteristics and a high signal-to-noise ratio.

[Brief explanation of the drawing]

1 and 2 are a schematic circuit diagram showing an embodiment of the magnetic recording/reproducing apparatus of the present invention, and a diagram showing frequency spectra of each part for explaining the recording method, respectively. 1...Magnetic recording/playback device, 2...Magnetic tape, 3S
...Audio input circuit, 3v...Video input circuit, 9a,
9b... Rotating magnetic head, 13... Changeover switch, 251, 25r... Frequency modulation circuit. Patent Applicant NEC Home Electro Figure 2 Procedural Amendment (Method) % Formula % 1. Indication of the case 1982 Patent Application No. 87288 2. Title of the invention 2 + II playback device 3. Case of the person making the amendment Relationship with Patent applicant address: 1-8-17 Umeda, Kita-ku, Osaka, Osaka 530 Name (Name) (193) Japan Ichiki Home Electronics Co., Ltd. Representative: Yo Sasaki 34, Agent address: 143 Tokyo 1-9-17-5 Omorihigashi, Ota-ku, Tokyo;
Date of amendment order: July 31, 1980 (shipment date) 6. Full text of the specification subject to amendment 7. Contents of amendment (1) The entire specification is amended as shown in the attached sheet.

Claims (1)

[Claims] A magnetic recording system that uses a predetermined frequency band between the frequency-modulated luminance signal and the low-frequency converted chromaticity signal to multiplex the frequency-modulated audio signal, and records the multiplexed signal on a magnetic tape. The reproducing device includes a frequency modulation circuit that frequency modulates the audio signal using an audio carrier wave having a frequency within the frequency band of the frequency-modulated luminance signal, and a frequency modulation circuit that modulates the frequency of the audio signal using an audio carrier wave having a frequency within the frequency band of the frequency-modulated luminance signal; A magnetic recording and reproducing device is provided with an audio recording means for recording the output of a modulation circuit on a magnetic tape using the frequency band of a luminance signal.