JPH02249105A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To record an FM sound without adding a head even for a long time mode by FM-modulating a sound signal of one channel at 1st and 2nd frequencies respectively and switching an FM modulated frequency every other tracks with a rotating head having a different azimuth angle on alternate tracks so that recording may be performed. CONSTITUTION:After the sound signal of one channel is inputted in an NR circuit 5 and twice compressed with logarithm, it is FM-modulated in FM modulation circuits 7 and 8, and respective output signals S1 and S2 from the FM modulation circuits are inputted in a recording switching circuit 41. At the time of recording, one of four sound heads mounted on a cylinder 13 and having different azimuth angles is selected with the aid of an output signal S4 from the recording switching circuit in a recording and reproducing switching circuit 9, and recording is performed on a magnetic tape in specified order. Therefore, the FM modulated carrier of the sound signal is alternately recorded every other tracks. Thus, one channel signal of FM sound is recorded without adding the head even for the long time mode.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus such as a video tape recorder (hereinafter referred to as VTR) for recording and reproducing audio signals.

Background of the Invention In recent years, camera-integrated VTRs (hereinafter referred to as movies) have become popular, and even in consumer VTRs, so-called FM-modulated audio signals are recorded using a rotating magnetic head. High-fidelity movies that can record and play back high-fidelity audio have been commercialized.

FIG. 3 shows a block diagram of a high-fidelity movie signal processing circuit.

In FIG. 3, two channels of audio signals are input to noise reduction circuits (hereinafter referred to as NR circuits) 6 and 6 through input terminals 1 and 2, and are logarithmically compressed by a factor of 2. 7 and 8, are FM modulated at carrier frequencies of 1.3 VPrl and 1.7 Vih, respectively, and are input to the recording/reproduction switching circuit 9. Further, a video signal is inputted to the video signal recording circuit 10 via the input terminal 3, the luminance signal of the video signal is FM modulated, and the color signal of the video signal is converted into a low frequency converted color signal 9, respectively, and the recording/reproduction switching circuit 1
1 is input.

During recording, the outputs of the FM modulation circuits 7 and 8 are mixed in the recording/reproduction switching circuit 9, and the azimuth angle ± of the υ cylinder 3, bay 7, and 13 mounted on the Four audio heads 14 (A
Rl)・15(ALl)・16 (Al1)・17(A
l2) (R2L indicates + or - of the azimuth angle) (Please select one from the following. In the overlap part, select two at the same time), ARl
・Magnetic tape in the order of ALl, Al1, Al2, ARl (
(not shown).

Similarly, the output of the video signal recording circuit 1o is outputted to the recording/reproducing switching circuit 11 by alternating the azimuths of the cylinders 13 with an azimuth angle of ±6 degrees according to a plurality of control signals inputted through the input terminals 4. Four image heads 18 (VRl)-19 (VLl)-20 (with different angles)
VH2) -21 (VL, ;) (R, L indicate azimuth angle +, -) Select one of them (two at the same time in the overlap part).

The video signal is overwritten in the order of vRl, vLl, VH2, VL2, and vR1 on the magnetic tape on which the audio signal has already been recorded so that the track patterns overlap. In addition, an output signal from an oscillation circuit 12 that can control oscillation stop by a control signal from an input terminal 4 is supplied to a flying erase head 22 mounted on a cylinder 13, and is used during recording (when connecting, inserting, etc.). The magnetic tape is erased in units of N (N: positive integer) frames prior to the audio head and video head.

During reproduction, the audio signals recorded on the magnetic tape are transmitted to the audio heads 14, 15, mounted on the cylinder 13.
The output of 16.17 is amplified by a plurality of control signals from the input terminal 4 in the recording/reproduction switching circuit 9, and then selected, and the 1.3 component and 1 .7 components and F respectively.
After FM demodulation in the M demodulation circuits 25 and 26, the NR circuits 27 and 28 respectively expand the two-channel reproduced audio signal by logarithmically logarithmically opposite characteristics to those at the time of recording, and output the reproduced audio signals of two channels through the respective output terminals 30 and 31. Output. Similarly, the video signal recorded on the magnetic tape is sent to the video head 1B mounted on the cylinder 13, and the output of the 19°20. Control signal 5.

The video signal reproducing circuit 29 selects the signal after amplifying it according to the
FM demodulates the luminance signal of the video signal, inversely transforms the low frequency converted color signal to demodulate the color signal, and outputs the reproduced video signal via the output terminal 32.

Problems to be Solved by the Invention However, in the above-described configuration, when a small cassette is used compared to the cassette used in consumer VTRs, which are currently widely used, when recording is performed at standard mode tape speed. Since it is possible to record only 60 minutes when recording in 2° or 3x mode, there is a demand for a tape speed mode that can record for even longer periods. However, in current high-fidelity movies, both the video head and the audio head are in standard mode (track width 58 μm).
The head width is selected to be around 26 μm so that it can be used in both the 3x mode (track width 19 μm) and the 3x mode (track width 19 μm).

Therefore, in order to make the recording mode even longer, it is necessary to add 4 audio heads and 8 video heads for a total of 8 heads, but there is a problem that physically it is not possible to mount 17 heads on the cylinder. A6 ・＼ru.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a magnetic recording and reproducing apparatus for movies and the like that can record FM audio even in a long-time mode without adding a head.

Means for Solving the Problems In order to solve the above problems, a first FM modulation circuit that FM modulates an input audio signal with a first carrier wave, and a second FM modulation circuit that FM modulates an input audio signal with a second carrier wave. an FM modulation circuit, a recording switch circuit which receives the output of the first FM modulation circuit, the output of the second FM modulation circuit, and a control signal for carrier selection; Tracks are recorded alternately on a magnetic tape using audio heads at different angles, the recorded magnetic tape is played back by the audio head, and the head playback output is output from the first track.
and the first and second F through the second bandpass filter.
The M demodulation circuit demodulates the audio signal. When the FM demodulation circuit output is selected using a switch that inputs the first and second FM demodulation circuit outputs, the configuration is configured to reproduce the audio signal. ing.

Function: According to the present invention, the input audio signal of one channel is FM-modulated at a first frequency and a second frequency, respectively, and two tracks are generated by a rotary head having a different azimuth angle every other track. The FM modulation frequency is switched and recorded on the magnetic tape.

During playback, the audio signals recorded on the magnetic tape are played back every other track using a rotating head with a different azimuth angle, the intermittent audio signals are demodulated using two FM demodulators, and the outputs of the two FM demodulators are controlled by a switch. You can select and play one continuous channel of audio signal.

EXAMPLE Hereinafter, a magnetic recording and reproducing apparatus in a long-time mode according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 shows signals of the main parts in FIG. 1.

In FIG. 1, one channel of audio signal is input to the NR circuit 5 through the input terminal 1, compressed logarithmically to 2 times, and then input to the FM modulation circuits 7 and 8, each having a carrier frequency of 1.31M. and 1.7 FM modulation, each F
The M modulation circuit output signals S1 and S2 are sent to the recording switch circuit 4.
The recording switch circuit output signal S4 is input to the recording/reproduction switching circuit 9. Further, a video signal is inputted to the video signal recording circuit 10 via the input terminal 3, the luminance signal of the video signal is FM modulated, and the color signal of the video signal is converted into a low frequency converted color signal. is input. During recording, the recording switch circuit output signal S4 is sent to the recording/reproduction switching circuit 9,
Four sound heads 14 (ARl), 1rs, (ALl) mounted on the cylinder 13 with different azimuth angles are controlled by a plurality of control signals input through the input terminal 4.
), 16 (AR2), 17 (AL2) (R and L indicate azimuth angles + and -). Please select one of them (two at the same time in the overlap area), AHl, ALl, AR2.
・Magnetic tape (not shown) in the order of AL2 and ARl
recorded in Therefore, the FM modulated carrier wave of the A-7 audio signal is recorded alternately as 1.3 total and 1.7 total every two tracks. In addition, the output of the video signal recording circuit 10 is sent to the recording/reproduction switching circuit 11, in which the signals are outputted alternately at an azimuth angle of ±6 degrees mounted on the cylinder 13 by a plurality of control signals inputted through the input terminal 4. Four long-time mode video heads with different azimuth angles 44 (VH1), 45 (VLl), 4 e
(VH2)・47(■L2) (R and L indicate azimuth angles + and -), select one of them (two at the same time in the overlap part).

The video signal is overwritten on the magnetic tape on which the audio signal has already been recorded so that the track patterns overlap in the order of VH1, ■L1, VH2, vL2, and ■R1. In addition, an output signal from an oscillation circuit 12 that can control oscillation stop by a control signal from an input terminal 4 is supplied to a flying erase head 22 mounted on a cylinder 13, and is used during recording (when inserting a joint). The magnetic tape is erased in units of N frames (N: a positive integer) prior to the audio head and video head.

During reproduction, the audio signals recorded on the magnetic tape are transmitted to the audio heads 14, 15, mounted on the cylinder 13.
16 and 17, and the output is amplified by a plurality of control signals from the input terminal 4 in the recording/reproduction switching circuit 9, and then selected.
Select ff1 component and 1.7 component, respectively, and install FM demodulation circuit 2.
After FM demodulation in step 5.26, the reproduction switch circuit 42 converts the signal into a continuous audio signal according to the control signal $3 from the input terminal 43, and the NR circuit 27 expands the signal logarithmically to twice that of the recording time. One channel of the reproduced audio signal is outputted via the output terminal 3Q. Similarly, the video signals recorded on the magnetic tape are transferred to the long-time mode video heads 4, 4, 45, 4 mounted on the cylinder 13.
The output of 6.47 is selected after being amplified by a plurality of control signals input through the input terminal 4 in the recording ρ■ raw switching circuit 11, and the luminance signal of the video signal is FM demodulated in the video signal reproducing circuit 29. , inversely converts the low frequency converted color signal, demodulates the color signal, and outputs the reproduced video signal 1 via the output terminal 32.
1 The l\-no number is output.

The audio head and the video head in this embodiment are both arranged at 90 degrees on the cylinder, and the heads are arranged so that the tracks formed by the audio head and the video head overlap each other, and the head height is adjusted. Needless to say, it has been decided. Also, when wrapping the tape around the cylinder, the corner is 27mm.
The angle is the sum of 0 degrees (for example, about 6 degrees).

Effects of the Invention As described above, according to the present invention, even in the long-time mode (track width 9.6 μm), the audio head (26 μm) is used to perform recording by alternating the recording angle for each track. By making the FM modulation frequency different for each two tracks, the reproduction signals from the two tracks before and after the reproduction track (recording azimuth is the same) are separated by a band-pass filter. Long time mode (
It is possible to record and reproduce one channel of audio signals even in a recording time that is twice as long as the current 3x mode, and the number of magnetic heads mounted on the cylinder can be increased to 13, making it possible to physically arrange them.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a magnetic recording/reproducing apparatus in a long-time mode according to an embodiment of the present invention, FIG. 2 is a timing diagram showing signals of the main parts in FIG. 1, and FIG. 3 is a conventional magnetic recording/reproducing apparatus. FIG. 1.3, 4.43... input terminal, 5, 27...
・NR circuit, 7, 8...FM modulation circuit, 9, 1
1...Record/playback switching circuit, 1o...Video signal recording circuit, 12...Oscillation circuit, 13...
...Cylinder, 14°15.16.17...Audio head, 18, 19°20.21...Video head (standard and 3x moto), 22... ...
Flying Erase Hesodo, 23.24...B
PF, 25.26...F'M demodulation circuit, 29...
...Video signal reproduction circuit, 30, 32...Output terminal, 41...Recording switch circuit, 42...
・Regeneration switch circuit, 44, 45, 46, 47...
・Video head (for long time mode)

Claims (1)

[Claims] a first modulation circuit that modulates an input signal at a first modulated frequency; a second modulation circuit that modulates the input signal at a second modulated frequency; and an output of the first modulation circuit and the second modulation circuit. What is claimed is: 1. A magnetic recording and reproducing apparatus comprising: a rotary head having mutually different azimuth angles for alternately selecting a modulation circuit output for every two tracks and recording on a magnetic tape for each track.