JPH01194108A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To overlap and record sound signals and a video signal on the same track by arranging the frequency spectrum of the PFM modulation signal of a second sound signal next to the high area of the frequency spectrum of a low-area-converted chrominance signal. CONSTITUTION:First, the sound signals are recorded and next, the video signal is recorded on them. A first sound signal is FM-modulated and recorded, the second sound signal is sampled, after that, converted into a digital signal word, further, converted into a PCM signal to which an error correcting word, a program searching word, etc., are added, further, PFM (pulse FM)-converted and recorded. The frequency spectra of the first and second sound signals are arranged next to the high area of the frequency spectrum of the low-area- converted chrominance signal. Thus, the sound signals and the video signals can be overwritten and recorded on the same track on a tape and can be reproduced.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention is applicable to a VCR (or VTR) with PCM audio recording or a VCR (or VTR) compatible with satellite broadcasting mode, in which a video recording head and an audio recording head are independent. The present invention relates to a helical scan type magnetic recording and reproducing apparatus having a head, which records an audio signal and a video signal in an overlapping manner on the same track on a tape, and reproduces the same.

"Prior Art" Conventionally, when recording audio signals, there are two methods: an analog signal recording method and a digital signal recording method. Among these methods, analog signal recording methods include an AC bias recording method in general RCD and an FM modulation recording method on an FM track in VH8 Hi-Fi. Further, as methods for recording digital signals, there are two methods: a method of recording a PCM audio signal instead of a video signal, and a method of compressing the signal to about 8 bits and recording the PCM audio signal on a dedicated track, as in the case of 8 mm video.

"Problem to be Solved by the Invention" In the VH3 Hi-Fi track, in order to record a PCM signal of about 14 bits that can support satellite broadcast mode audio at the same time as recording a video signal, an additional recording track is not provided. , recording and playback is not possible. Also,
Even if you try to record a video signal after recording an audio signal using the overwriting method, since the audio signal has a wide band on a VH3 Hi-Fi track, it will interfere with the color signal and brightness signal of the video signal, and recording will not be possible. .

The present invention provides a method for recording an audio signal and overlapping a video signal thereon in a state that does not overlap with the color signal of the video signal and is also acceptable for the luminance signal. The purpose is to obtain.

"Means for Solving the Problems" The present invention has been made to solve the above problems, and is a helical scan type having an independent video recording head and an audio recording head. and second
In a magnetic recording and reproducing apparatus that records one selected audio signal and then overwrites and records a video signal, the luminance signal of the video signal is FM modulated, and the chrominance signal is FM-modulated. After being separated, it is low frequency converted and F
a video signal processing circuit for processing the video signal so that it is placed in a band below the M modulation signal; and a video signal processing circuit for recording the processed video signal on the tape with the azimuth of the video track tilted by a few degrees with respect to the adjacent track. a video head, an FM modulation circuit for FM modulating the first audio signal, an LPF for limiting high frequency components of the second audio signal, and a sampling of the high frequency limited second audio signal. an A/D conversion circuit that converts the sampled signal into a digital signal word; and an NRZ signal that adds an error correction word, a control word, an error detection word, and a cue word to the digital signal word. a PCM processor that converts the PCM signal into a PCM signal of the form
A PFM encoder that modulates the frequency spectrum of the PFM modulated signal is arranged adjacent to the high frequency spectrum of the low-pass converted color signal, and lowers the modulation index, and the sideband components thereof are arranged on the first upper side. A BPF for limiting within the waveband spectrum and blocking the first lower sideband spectrum, a switching circuit for selectively switching when recording the first and second audio signals, and FM modulation. It is possible to record and reproduce both the first audio message and the second pulse-FM modulated audio signal, and when recording on the tape, the azimuth difference between the tracks of the video signal and the audio signal is several tens of An audio head that records with the azimuth of the audio track tilted at an angle of several tens of degrees with respect to the adjacent track so that the azimuth is more than that of dust, and an audio recorder that detects the PFM modulated signal carrier wave and the F and M modulated signal carrier wave from the reproduced audio signal. a mode detection circuit, a switching circuit that switches the playback signal using the mode detection circuit, a channel switcher that switches the playback output channel in synchronization with the audio head, an AGC circuit that controls the playback signal level to a constant level, and a necessary signal spectrum. a waveform shaping circuit that converts the reproduced signal into a PFM signal, and a waveform shaping circuit that converts the PFM signal into an NRZ signal.
A PFM decoder that returns to the playback PCM signal of the format, and a playback PCM signal.
It is equipped with a PCM processor that detects errors from CM signals, corrects errors, converts them into reproduced digital signal words, decodes control codes, and outputs them, and a D/A conversion circuit that converts the reproduced digital signals into analog signals. It is.

"Function" When recording on a tape, the azimuth of the video track is set by several degrees relative to the adjacent track, specifically ±3 to 10 degrees, and the azimuth of the audio track is set several dozen degrees relative to the adjacent track, specifically has an inclination of ±20 to 35 degrees, and the azimuth difference between the video and audio tracks is several tens of degrees, specifically 20 degrees or more, and when recording, the audio signal is first recorded, and then the video signal is Record over and over again.

Among the video signals, the luminance signal is FM-modulated, and the chrominance signal is separated, then low-frequency converted and placed in a band below the FM modulation signal. Both signals are recorded on the tape by a video head.

The first audio signal is FM modulated and recorded onto the tape by the audio head. After the second audio signal is sampled,
It is converted into a digital signal word by an A/D converter, and then converted into a PCM signal to which an error correction word, a control word, an error detection word, a cue word, etc. are added, and then PFM (pulse FM) modulated and sent to the audio head. recorded on tape.

The frequency spectra of the first and second audio signals are arranged adjacent to the high frequency spectrum of the low frequency converted color signal. The second audio signal is a PFM modulation index (Δf
FM/fPQ1) is 0.5 or less and its sideband components are limited within the first upper sideband spectrum, and the first lower sideband spectrum is blocked.

Magnetic recording is performed under the above conditions.

During playback, when the audio signal is played back from the tape by the head, the mode detection circuit detects whether it is the carrier wave of the PFM modulation signal or not.
It detects whether it is the carrier wave of the FM modulation signal and switches the switching circuit. In the case of a PFM modulated signal, the output level is made constant by the AGC circuit, the PFM signal is made by the waveform shaping circuit, the predetermined signal spectrum is made by the filter, and the NR is made by the PFM decoder.
The reproduced PCM signal is in Z format. This PCM signal is P
The CM processor corrects errors and the like, and the D/A conversion circuit converts it into an analog signal and outputs it. Furthermore, in the case of an FM modulated signal, it is outputted via a conventionally known normal reproduction circuit.

"Example" Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, (la) (lb) are the L and R audio signal input terminals of the PCM, which is the second audio signal, and these audio signal input terminals (la) (lb) are in recording mode (III).
A switching circuit (2) switches between IEC) and playback mode (PB).
a) LPFC low pass filter limiting to 24K Hz band via (2b) (3a) (3b), amplifier (4a) (4b), 44.1KHz sampling and hold circuit (5a) (5b), 14 P through the A/D conversion circuit (6) that converts it into a bit digital signal
It is coupled to a PCM processor (7) for converting into CM signals. This PCM processor (7) includes R and L sampling data input terminals (8a) (8b), a switching circuit (9), a correction word generation circuit (10), an address controller (51), an interleave memory (11), an error It is coupled to a PCM signal output terminal (13) via a detection word generation circuit (12). This output terminal (13) is coupled to a PFM encoder (14) for Hahals FM modulation. As shown in Figure 2, this PFM encoder (14) consists of an NRZ signal input terminal, two frequency input terminals, two NAND circuits, one OR circuit, and one flip-flop circuit, and its output terminal is FM A BPF (band pass filter) (15) for filtering only the signal carrier and the first upper sideband, an amplifier (16), an FM signal (A-FM) which is the first audio signal, and a second audio signal. Switching circuit (17a) for switching a certain PCM signal
(17b), coupled to rotating audio heads (19a) (19b) via recording amplifiers (18a) (18b),
A magnetic tape (20) is facing the viewer.

The FM L and R audio input terminals (21a) (21b) into which the first audio signal is input are connected to the amplifier (22a) (22
b), 20 to 7 L P F (23a) (
23b), amplifier (24a) (24b), FM modulation circuit (24b) that modulates with 1.3M7 and 1.7M7 FM carrier waves.
5a) (25b), LPF that limits only the fundamental wave (
26a) (26b), amplifier (27a) (27b)
A-F of the switching circuit (17a) (17b) via
It is connected to the M side.

The rotating audio head (28a) (28b) on the playback side includes a playback amplifier (29a) (29b) and a mode detection circuit (3).
0), the switching circuit (31a) switches between PCM, which is the second audio signal, and A-FM, which is the first audio signal.
31b). This switching circuit (31a)
The PCM side of (31b) is an L/R channel switcher (
32), AGC circuit that absorbs fluctuations in output level (33)
) and AGC detection circuit (34), BPF (35) that passes 3.6 to 1.0M7, waveform shaping circuit (36) that shapes the waveform and returns it to a PFM signal, and decodes it to an NRZ format PCM signal. The reproduced PCM signal input terminal (3) of the PCM processor (7) is connected via the PFM decoder (37).
8).

The reproduced PCM signal input terminal (38) of this PCM processor (7) is connected to an error data detection circuit (39), an address controller (40), an interleave memory (41), an error data correction circuit (42), and a switching circuit (43). L and R output terminals (44a) (44b) for playback data via
is combined with This output terminal (44a) (44b
) is a D/A conversion circuit (45) that converts into an analog signal;
The switching circuit (
2a) is coupled to the PB side of (zb), and furthermore, the L
P F (3a) (3b) has an amplifier (47a)
(47b) are coupled to the L and R output terminals (48a) and (48b) of the PCM, which are the second audio signals.

A-F of the switching circuit (31a) (31b) on the reproduction side
On the M side, amplifiers (49a) (49b), B P F
(50a) (50b), limiter (60a) (6
0b), FM demodulation circuit (61a) (61b), LP
F (62a) (62b), amplifier (63a) (6
3b) through the first audio signal L and R audio FM
Signal output terminals (64a) (64b) are coupled.

In the above circuit configuration, when L and R PCM audio signals, which are the second audio signals, are input to the input terminals (1a) (1b), they pass through the amplifiers to the switching circuits (2a) (2b).
sent to. Assuming that it is switched to the recording (REC) side, input to L P F (3a) (3b) is limited to a band of 24K) Iz. Furthermore, the amplifier (4
a) After passing through (4b), it becomes a 44°1K)lz sampling signal in the sampling and hold circuit (5a) (5b), which is further converted into a 14-bit digital signal in the A/D conversion circuit (6), and then sent to the PCM processor ( 7). Then, this PCM processor (7) generates a general PCM signal to which correction words, control words, error detection words, cue words, etc. are added. This PC
The M signal format is N RZ (Non Return to
A signal with a waveform as shown in Figure 3(b) is output as a Zero) signal, which is PFM-modulated by a PFM encoder (14) as shown in Figure 3(c) to convert the frequency spectrum of the signal, and further , B P F (15) as shown in FIG. 3(d) and FIG. 5(C).
6-1.0M1 (z is reduced to only the carrier and first upper sideband component of the FM signal. Here, the modulation index of the PFM signal (
ΔfFM/f, CM) shall be 0.5 or less.

Note that Δf group: maximum FM carrier deviation frequency.

f PCM: N Basic bit frequency of RZ signal.

The output of the B P F (15) passes through an amplifier (16), further passes through the PCM side of the switching circuit (17a) (17b), is amplified by the amplifier (18a) (18b), and is sent to the rotating audio head (19a) (19b). ) by tape (20)
recorded above.

When the audio FM signal, which is the first audio signal, is input from the A-FM input terminals (21a) (21b), the LPF (2
3a) (23b) limits the band to 20KHz, FM
Each L and R signal is 1 in the modulation circuit (25a) (25b)
．． It is modulated with 3MHz and 1.7MHz FM carriers.

The FM modulated signal is L P F (26a) (26
b), the A-FM signal is limited to only the fundamental wave, and the A-FM signal is passed through the switching circuit (
17a) Pass through the A-FM side of (17b) to the amplifier (18
a) Amplified by (18b) and rotated audio head (19a)
) (19b) is recorded on the tape (20).

whether the second audio signal is a PCM signal or the first audio signal is a PCM signal;
Regardless of whether the audio signal is an A-FM signal, the azimuth of the audio track on the tape (20) is ±20 to 35 with respect to the adjacent track, as shown by the dotted line in FIG.
Record the slope in degrees.

After recording this first or second audio signal, a video signal is overwritten and recorded. In other words, the video track is the fourth track.
As shown by the solid line in the figure, the azimuth is recorded with an inclination of ±3 to 10 degrees with respect to the adjacent track, and the azimuth difference between the audio/video tracks is 20 degrees or more.

Incidentally, among the video signals, the luminance signal is FM-modulated, and the color signal is separated and then low-band converted and placed in a band below the FM modulation signal.

Next, the case of reproduction will be explained. The recording signal on the tape (20) is recorded by rotating audio heads (28a) (28b,)
and amplified by amplifiers (29'a) (29b). In the mode detection circuit (30), the P of the reproduced signal is
CM @ By detecting the transmitted signal, the switching circuit (3
1a) A-FM of the first audio signal in (31b)
To automatically switch between the signal side and the PCM signal side of the second audio signal.

If it is a PCM signal, the reproduction signal is selected by the L/R channel switcher (32), and the AGC circuit (33)
The AGC detection circuit (34) absorbs fluctuations in the output level, and the B P F (35) outputs 3.6 as shown in Figure 5(c).
-1゜0M) (passes only the signal of z and removes unnecessary signals. Figure 3 (d) from this B P F (35)
) is output from the waveform shaping circuit (36) as shown in Figure 3 (e).
), and is returned to a PFM signal, and this reproduced PFM signal is sent to the PFM decoder (37) as shown in Figure 3 (
The signal is decoded into an NRZ format PCM signal as shown in f).

This PCM signal is input to a PCM processor (7), subjected to error checking and error correction, and converted into 14-bit sampling data. Furthermore, the D/A conversion circuit (
45), the signal is returned to an analog signal, and the switching circuit (2a) (
2b) via the PB side, L P F (3a) (3b)
, the sampling noise is removed, and the PCM audio signal, which is the second audio signal, is sent to the output terminals (48a) (48b
). When the reproduction signal is detected as an A-FM signal by the mode detection circuit (30), the switching circuit (31a)
(31b) is switched to the A-FM side, and B P F (
50a) (50b), limiter (60a) (60b
), FM demodulation circuit (61a) (61b), L p F
After passing through (62a) and (62b), the A-FM audio signal, which is the first audio signal, is output from output terminals (64a) and (64b).

The video signal is also reproduced and displayed by a known reproduction circuit (not shown).

"Effects of the Invention" According to the present invention, in a VH3 Hi-Fi track,
Simultaneously with video signal recording, either the FM signal of the first audio signal or the PCM signal of the second audio signal can be recorded and played back without additional recording tracks.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a magnetic recording/reproducing apparatus for embodying the magnetic recording/reproducing apparatus according to the present invention, Fig. 2 is a block diagram of a PFM encoder, Fig. 3 is an output waveform diagram of each part, and Fig. 4 is a tape FIG. 5 is a frequency characteristic diagram. (la) (lb) -P CM audio signal input terminal, (
2a) (2b) -mode switching circuit, (5a) (5
b)...Sampling and hold circuit, (6)...
... A/D conversion circuit, (7) ... PCM processor,
(14)-P F M encoder, (19a) (19b
)...Rotary audio head for recording, (20)...Magnetic tape, (28a) (28b)...Rotary audio head for playback, (30)...Mode detection circuit, (31a) (
31b) -...Switching circuit, (32)...=Channel switcher, (36)...Waveform shaping circuit, (37)...
・PFM decoder, (45)...D/A conversion circuit, (
48a) (48b)...Audio PCM signal output terminal. Applicant Fujitsu General Ltd. Figure 3 T1: TT2 = 2nd Figure 4 Figure 5

Claims (1)

[Claims] (1) A helical scan type having independent video recording heads and audio recording heads, with first and second recording heads on the tape.
In a magnetic recording and reproducing apparatus that records one selected audio signal and then overwrites and records a video signal, the luminance signal of the video signal is FM modulated, and the chrominance signal is FM-modulated. After being separated, it is low frequency converted and F
a video signal processing circuit for processing the video signal so that it is placed in a band below the M modulation signal; and a video signal processing circuit for recording the processed video signal on the tape with the azimuth of the video track tilted by ± several degrees with respect to the adjacent track. a video head, an FM modulation circuit for FM modulating the first audio signal, an LPF for limiting high frequency components of the second audio signal, and a sampling of the high frequency limited second audio signal. an A/D conversion circuit that converts the sampled signal into a digital signal word; and an NRZ signal that adds an error correction word, a control word, an error detection word, and a cue word to the digital signal word. a PCM processor that converts the PCM signal into a PCM signal of the form; a PFM encoder that pulse-FM modulates the PCM signal; A BPF for lowering the modulation index and limiting its sideband components to within the first upper sideband spectrum and blocking the first lower sideband spectrum, and the first and second audio signals. A switching circuit that performs selective switching when recording a signal, and an FM modulated first
Both the audio signal and the pulse FM modulated second audio signal can be recorded and reproduced, and when recording on the tape, the azimuth difference between the tracks of the video signal and the audio signal is several tens of degrees or more. An audio head that records an audio track with an azimuth tilt of ± several tens of degrees with respect to an adjacent track, and an audio recording mode detection circuit that detects a PFM modulated signal carrier wave and an FM modulated signal carrier wave from a reproduced audio signal. A switching circuit that switches the playback signal using this mode detection circuit, a channel switcher that switches the playback output channel in synchronization with the audio head, an AGC circuit that controls the playback signal level to a constant level, and a filter that passes the necessary signal spectrum. A waveform shaping circuit converts the reproduced signal into a PFM signal, a PFM decoder converts the PFM signal into a reproduced PCM signal in NRZ format, and detects errors from the reproduced PCM signal, performs error correction, converts it into a reproduced digital signal word, and converts the control code. A PCM processor that decodes and outputs the data, and a D/D converter that converts the reproduced digital signal into an analog signal.
1. A magnetic recording and reproducing device comprising: an A conversion circuit. (2) Claim that the azimuth of the video track is ±3 to 10 degrees with respect to the adjacent track, the azimuth of the audio track is ±20 to 35 degrees with respect to the adjacent track, and the azimuth difference between the video and audio tracks is 20 degrees or more Section (1)
The magnetic recording/reproducing device described above. (3) Modulation index of pulse FM modulation signal (Δf_F_M:
Claim (1) in which the maximum FM carrier deviation frequency (/f_P_C_M: fundamental bit frequency of NRZ signal) is 0.5 or less
) or the magnetic recording/reproducing device described in (2).