JPS6333355B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a helical scan magnetic recording and reproducing apparatus that records video and audio signals by forming diagonal tracks on a magnetic tape using a rotating magnetic head. The present invention relates to a magnetic recording/reproducing apparatus that records data on a diagonal track.

Conventional simple type using cassette/magnetic tape
A VTR uses a system in which a rotating head records video signals on diagonal tracks, and control signals and audio signals are recorded on two longitudinal tracks provided at both ends of a magnetic tape. An example of such a cassette helical VTR is shown in FIG. The figure shows an example of a tape loading state in the VTR, in which 1 is a cassette, 2 is a magnetic tape, and 3 and 4 are rotating magnetic heads, which are arranged on a rotating head drum as shown. 9 is a capstan, 8 is a pinch roller, and 8 and 9 feed the tape 2 in the direction of arrow 10 at a constant speed. As a result, the magnetic tape 2 is wound around the circumferential surface of the head drum and runs, and as the rotary heads 3 and 4 rotate in the direction of arrow 11, a diagonal track is formed on the magnetic tape. 5 is a full-width erasing head for the tape, 6 is an erasing head for only audio tracks, and 7 is a recording/reproducing head for audio and control signals.

FIG. 2 is a schematic diagram showing an example of a pattern on a magnetic tape recorded by the VTR shown in FIG. 1, and 12 in the figure is a control signal recording track;
Reference numeral 13 denotes an audio signal recording track, and 14 a video track on which a video signal is recorded by two rotating magnetic heads 3 and 4. A video signal of one line and one field is recorded using a known azimuth recording method. Also, the audio signal is recorded by the fixed head 7 on the audio track 13 formed in the longitudinal direction at the end of the width direction of the tape, and at the same time, the CTL for synchronizing playback is recorded on the control track 12 at the other end.
The signal is recorded.

On the other hand, in order to reduce the consumption of magnetic tape and make tape cassettes and devices smaller and lighter, the recording trajectory width and magnetic tape running speed are reduced by increasing the recording density of video signals. It is. However, when the running speed of the magnetic tape is extremely low, it is difficult to ensure sufficient frequency characteristics of the audio signal by the fixed head. To this end, a method has been considered in which a composite signal of a video signal and an audio signal is recorded and reproduced using the same rotating magnetic head.

FIG. 3 is a curve diagram showing an example of the frequency band of a video/audio signal when a composite signal of a video signal and an audio signal is recorded by a rotating magnetic head. In the figure, 15 is the low frequency converted color signal band, and 17 is FM
16 is a modulated luminance signal band, and 16 is an FM-modulated audio signal band. Note that this method of dividing the bands is just one example, and other combinations may be used.

Conventionally, in such a system, the video signal and the audio signal are combined and recorded, so it has been impossible to record the audio signal separately.

The present invention is directed to recording video signals and audio signals on diagonal tracks using such a rotating magnetic head, and in order to facilitate recording and reproduction, a recording track for separately recording audio is provided in the longitudinal direction of the tape, and these recording tracks are also provided. The present invention provides a magnetic recording and reproducing device capable of appropriately reproducing.

FIG. 4 is a schematic diagram showing an example of a magnetic tape pattern according to the magnetic recording device of the present invention.

In the figure, 18 is a CTL control signal recording track, and 19 is a track on which a video/audio composite signal is azimuthally recorded in the main area (first area) on the magnetic tape by a rotating magnetic head. Reference numeral 51 denotes an audio recording track formed in a region (second region) along the edge of the magnetic tape.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is a block diagram showing an embodiment of an electric circuit for normal recording/playback and audio dubbing of a VTR according to the present invention. In the figure, during normal recording, the recording/reproduction signal switching analog switch 24 is set to recording mode (Rec), and when a video signal is input, the luminance component of the video signal is extracted by a low-pass filter (LPF) 20 that extracts the luminance signal, and is modulated by FM. The signal is frequency-modulated by an adder 21 and added to an adder 22 . Further, the color signal component of the video signal is extracted by a band pass filter (BPF) 25, converted to a low frequency by a frequency converter 26 that converts the color signal to a low frequency, and then converted to a low frequency by an adder 22.
added to.

On the other hand, the audio signal is frequency modulated by an FM modulator 27 and added to an adder 22.

As shown in FIG. 3, the audio frequency band 16 falls between the low frequency converted color signal 15 and the frequency modulated luminance signal 17. The output of the adder 22 is sent to the recording amplifier 23, and the output of the analog switch 24 is sent to the recording amplifier 23.
Applied to the rotating magnetic head 43 via the Rec terminal,
It is recorded on videotape 45.

Also, during normal playback, the analog switch 24 switches to playback mode (Play), and the dubbing signal,
The normal playback signal switching analog switch 30 is switched to the normal playback position N. That is, the video and audio signals reproduced by the rotating magnetic head 43 are transmitted to the reproduction amplifier 28 through the analog switch 24.
The output of the playback amplifier is a high pass filter (HPF).
31, LPF34, and BPF36. Reference numeral 31 denotes an HPF for extracting the frequency-converted luminance component (17 in FIG. 3), and its output passes through an FM demodulator 32 and is input to an adder 33. 34 takes out the color signal component (15 in Figure 3) whose frequency has been converted to a low frequency range.
The color signal returned to its original state through the frequency demodulator 35 by the LPF is added to the adder 33. The output of 33 is a reproduced video signal. On the other hand, the frequency-modulated audio signal (16 in Figure 3) is BPF
36, the audio signal is input to the FM demodulator 37, and the audio signal is output via the analog switch 30.

In the apparatus of the above type, in this embodiment, in order to enable audio dubbing, a track dedicated to dubbing recording is provided, and a fixed magnetic head 44 for dubbing is provided.

During audio dubbing recording, the dubbing recording/playback signal switching analog switch 46 is switched to dubbing position A. The audio signal separated from the video/audio composite signal passes through an FM demodulator 37 and then an adder 38.
is input. On the other hand, the post-recording audio signal is also added to the adder 3.
8, the addition level adjuster 39 attached to the adder 38 freely changes the mixing ratio of the pre-dubbing audio signal and the post-recording audio signal, and outputs the mixture from the adder 38. The output of 38 is input to an adder 40 where it is input to a pilot signal generator 4.
A pilot signal is added from 1. Here, as shown in FIG. 6, the pilot signal 52 is selected to be 10 Hz below the audio band 53. Note that the band of this pilot signal may be set to any range as long as it does not affect the audio signal. The function of this pilot signal will be described when reproducing an after-recording audio signal. The output of the adder 40 is input to a recording amplifier and bias adder 42, where a bias signal is added by a bias signal generator 43. The output of the circuit 42 passes through an analog switch 46 and is sent to the video tape 4 by a fixed magnetic head 44 for dubbing.
5 is recorded on a track dedicated to dubbing recording.

After recording the audio dubbing signal, when the playback mode is set, the analog switches 24 and 26 are switched to the Play position. The output from the fixed head 44 is connected to a reproducing amplifier 47 through an analog switch 46. The output of the playback amplifier 47 is then sent to a band pass filter (BPF) 48 that passes only the dubbing audio signal (53 in Figure 6) and a band pass filter (BPF) 49 that extracts the pilot signal component (52 in Figure 6). be guided. The output of the BPF 49 is input to a pilot signal detector 50, and when the detector 50 detects the pilot signal, it switches the output mode switching analog switch 30 to the dubbing audio reproduction position A. The dubbing audio signal that has passed through the BPF 48 is then output via the analog switch 30. That is, when there is a pilot signal, the mode is such that the dubbing audio signal recorded on the post-recording dedicated track is outputted from the audio output terminal as reproduced audio. This output audio signal is a signal obtained by combining the post-recording audio signal input to the adder 38 and the audio signal reproduced from the original recording track at a desired ratio. On the other hand, when there is no pilot signal, the analog switch 30 is switched to the normal playback position N, and the audio output terminal is connected to the video and
This is a mode in which the audio signal separated from the audio synthesis signal is output as output playback audio.

FIG. 7 is a block diagram of a recording and reproducing section showing an embodiment of a simplified VTR according to the present invention. In the figure,
55 is a cassette for storing a magnetic tape 56;
7.58 The first recording and reproducing means is a rotating magnetic head for recording and reproducing a video/audio composite signal. The rotating magnetic head rotates at a constant speed in the direction of arrow 64. 60 is a capstan, 59 is a pinch roller, and the tape 56 is pressed against the capstan and the pinch roller, and the tape is fed at a constant speed in the direction of arrow 63 by constant rotation of the capstan. 6
1 is the videotape full width erase head, 62 is the CTL
Fixed head for recording and reproducing control signals,
Reference numeral 65 denotes a dedicated fixed head for recording and reproducing the audio dubbing signal of this embodiment, which is related to the second recording and reproducing means.

In the above-described embodiments, it is assumed that audio dubbing is performed as a separate recording of audio, but the present invention is not limited to this.

Further, in order to enable the audio dubbing recording to be performed again, it is also possible to provide an erasing head for erasing the post-recording track in front of the fixed head 65 for dubbing the tape.

Similarly, the present invention is not limited to the above embodiments, but can be modified as appropriate within the scope of the claims.

As explained in detail above, the magnetic recording and reproducing apparatus of the present invention is capable of recording and reproducing audio separately in a system in which video signals and audio signals are recorded and reproduced on diagonal tracks on a magnetic tape using a rotating head. In addition, the separately recorded audio signal can be played back as appropriate, and has a great effect in facilitating recording and playing in the above-mentioned equipment that separately records audio.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a recording and reproducing section showing an example of a simple VTR using a conventional method, Fig. 2 is a diagram of a recorded track pattern on a magnetic tape by the device shown in Fig. 1, and Fig. 3 is a diagram of the device shown in Fig. 1. FIG. 4 is a diagram of a frequency band curve of a video and audio synthesized signal recorded by a rotating head in FIG. 4, a recording track pattern diagram on a magnetic tape according to the present invention, and FIG. A block diagram showing
FIG. 6 is a frequency band curve diagram of a pilot signal and an audio signal of a longitudinal audio track in an apparatus according to an embodiment of the present invention, and FIG. 7 is a diagram showing the configuration of a recording and reproducing section of a simple VTR according to this embodiment. It is. 30... Output mode switching switch, 55...
Cassette, 56... Magnetic tape, 57, 58...
Rotating head, 59...pinch roller, 60...capstan, 61...full width erasing head, 62...
Control signal head, 65...Fixed head for audio recording and playback, 63...Tape running direction, 64
...Rotating head rotation direction.

Claims (1)

[Claims] 1. A first recording and reproducing means for recording and reproducing video signals and audio signals using a rotary head in a first area extending in the longitudinal direction on a magnetic tape; A second area for recording and reproducing an audio signal in a second area extending in the longitudinal direction on the top.
a recording/reproducing means; a switching means for selectively outputting the audio signal reproduced by the first recording/reproducing means and the audio signal reproduced by the second recording/reproducing means as a reproduced audio signal; 1. A magnetic recording and reproducing apparatus comprising: switching control means for controlling said switching means based on whether or not an audio signal is recorded in a second area.