JPS61253660A - High fidelity vtr - Google Patents

Abstract

PURPOSE:To execute the program searching of music by an index search by deciding whether a video signal exists in a signal or not, executing a normal reproduction when the video signal does not exist and also inhibiting the muting of a voice reproduced by a sound recording and reproducing head for high fidelity. CONSTITUTION:When bringing only a sound signal to high fidelity recording, an index signal is recorded onto a tape. From a sound signal input terminal 41, a sound signal is inputted, but from a video signal input terminal 21, a video signal is not inputted, therefore, a video signal existence detecting circuit 23 outputs the signal of video signal non-existence. Therefore, a switching circuit 24 mutes the video signal by grounding the output of a video clamping circuit 22, or the like. As a result, from a modulating circuit 25, the constant sine wave signal of non-modulation is outputted, and recorded to the tape by a video signal recording/reproducing head 27. On the other hand, the sound signal inputted from a sound signal input terminal 41 is superposed and written onto the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a high-fidelity (HiFl) VTR, and in particular to a high-fidelity (HiFl) VTR having an index search function that allows music selection like an audio deck.
Regarding.

(Background of the Invention) The basic configuration of a conventional VTR having an index search function is explained using FIG. ! I will clarify. $P in the diagram, 1
is an input terminal to which an index signal is input, and the index signal includes, for example, the video head switching signal 3.
0 Hz is used. Reference numeral 2 denotes an index signal recording circuit, which outputs an index signal at the start of recording. 3 is an index signal recording head, and more specifically, a full width erasing head is used.

4 is an index signal detection device, for example, a Hall sensor is used. 5 is an index signal amplification and shaping circuit, and 6 is a system control circuit consisting of a micro combinator and the like. 7 is a drive device that provides driving force to the capstan 13 and the reel.

Further, 8 is a cassette tape attached to the reel, 9
1 is a cylinder around which a pair of magnetic heads for recording video signals and a pair of magnetic heads for recording high-fidelity audio signals are attached at appropriate intervals; 10 and 11 are loading posts; 12 is an audio erasing head and an audio cylinder; - Control head, 13 is a capstan, 14 is a pinch roller. Further, 15 indicates a magnetic tape, the solid line indicates the tape position when it is not loaded, and the dotted line indicates the tape position when it is loaded.

Now, in a VTR having such a configuration, when recording video and high-7-eye audio, the index signal input from the input terminal 1 is output from the index signal recording circuit 2 for several seconds.

This index signal is then recorded by the index signal recording head 3 onto the magnetic tape 15 in the loading state.

Next, a video signal is sent to a pair of magnetic heads attached to the cylinder/cylinder 9, and an audio signal is sent to a pair of high-fidelity audio signal recording magnetic heads. Therefore, a video signal and an audio signal are recorded on the magnetic tape 15 in a superimposed manner following the index signal.

When performing an index search from a magnetic tape on which a video signal and a high-fidelity audio signal are recorded following one index signal, the tape 15 is placed in the unloading position (solid line position), and the tape 15 is placed in the unloading position (solid line position) and the fast forward or winding A return is made. At this time, the index signal detection device 4 comes into contact with the magnetic tape 15 and detects the index signal.

When the index signal detection device 4 detects an index signal, the index signal is amplified and waveform-shaped by the index signal amplification and shaping circuit 5 and input to the system control circuit 6. When the system control circuit 6 detects that the index signal has been input from the index signal amplification and shaping circuit 5, it sends a control signal to a loading mechanism (not shown), loads the magnetic tape 15, and plays the fast forward mode. to go into.

At this time, the audio is being muted.

The operator views the video displayed on the television screen by fast forward playback and determines whether or not it is the desired video.

Then, if the video is what you want, turn on the play button.
Normal playback is performed and the desired video is played back. At this time, the audio mute is canceled and the audio is output.

On the other hand, if it is not the current video, the index search is performed again.

As described above, according to a conventional high-fidelity VTR having an index search function, it is possible to locate the beginning of a desired video in a short time.

By the way, when an IEVTR is used as an audio deck and an attempt is made to locate the beginning of a song or music recorded on the magnetic tape 15 using the index signal, the following inconvenience occurs. . That is, when the index signal is detected by the index signal detection device 4 and the magnetic tape 15 is loaded as described above, the fast forward 9 playback state is entered.
No video signals are recorded on TV 5, only audio signals are recorded, so no video appears on the TV screen. Also, since the audio is mediated, the audio cannot be heard either.

For this reason, there is a problem in that the operator cannot locate the beginning of a song recorded on the magnetic tape 15.

(Object of the invention) The object of the present invention is to eliminate the problems of the prior art described above,
It is possible to locate the beginning of a high-fidelity recorded song by index search.

(Summary of the Invention i) A feature of the present invention is that in a high-fidelity VTR having an index search function, it is determined whether or not there is a video signal in the signal reproduced by the video signal recording/reproducing head, and when there is no video signal, In addition to normal playback, muting of the audio played by the Hi7E audio recording/playback head is prohibited, allowing music selection like a conventional audio deck.

(Examples of the Invention) The present invention will be described below with reference to Examples. Figure 1 shows
1 shows a block diagram of an embodiment of the present invention.

In FIG. 1, 21 is a video signal input terminal, 22 is a video clamp circuit, 23 is a video signal presence detection circuit, 24 is a switching circuit, 25 is a modulation circuit, 26 is a recording amplifier,
27 is a video signal recording/playback head; 28 is a playback amplifier; 2
9 is a demodulation circuit; 30 is a video signal presence/absence detection circuit that detects the presence or absence of a video signal depending on whether the input signal is DC, for example; 31 is a video signal output amplifier; and 32 is a video signal output terminal.

Further, 41 is an audio signal input terminal, 42 is a noise reduction/audio signal amplification circuit, 43 is a modulation circuit, 44 is a recording amplifier,
45 is a high-fidelity audio signal recording/reproducing head, 46 is a reproduction amplifier, 47 is a demodulation circuit, 48 is an audio signal muting circuit, 49 is an audio signal output amplifier, and 50 is an audio signal output terminal.

Note that 4 is an index signal detection device, 5 is an index signal amplification and shaping circuit, and 6 $P and 7 are a system control circuit and a driving device, respectively. These are the same or equivalent to the conventional devices with the same reference numerals in FIG.

Further, FIG. 3 is a block diagram showing a specific example of the video signal presence/absence detection circuit 30. The mosquito video signal presence/absence detection circuit 30 consists of a peak detector 30&, a comparator 30b, and an R87 lip flop 3C. Peak detector 30a When a K video signal is input, its peak voltage is equal to the reference voltage V
Since the signal becomes very high, a pulse signal is output from the comparator 30b, and the R87 logic flop 3C is set. On the other hand, when a DC signal indicating that no video signal is recorded is input to the peak detector 30&, the reference voltage V
is set larger than the voltage of the DC signal, so
A low level signal is output from the comparator 30b, and R8
7 rig 70 tube 3C is not set. in this way,
According to the video signal presence/absence detection circuit 30, it is possible to identify whether the input signal is a video signal or not. Note that the video signal presence/absence detection circuit 3o is not limited to the circuit shown in FIG. 3, and other circuits can of course be used.

Next, the operation of this embodiment having the above configuration will be explained.

When recording a video signal and a high-fidelity audio signal on a magnetic tape, an index signal is first recorded over the entire width of the tape for several seconds using a single index signal recording head, as in the conventional apparatus.

Next, a video signal and an audio signal are input from the video signal input terminal 21 and the audio signal input terminal 41, respectively. A video signal input from the video signal input terminal 21 is sent to a video clamp circuit 22 and a video signal presence/absence detection circuit 23. The video signal presence detection circuit 23 confirms the presence of the video signal, and the switching circuit 24 detects the presence of the video signal.
1 switching circuit 2 so as to connect the modulation circuit 25 and the modulation circuit 25.
Control 4. After the video signal sent to the modulation circuit 25 is modulated by the video modulation circuit 25, the modulated signal is amplified by the recording amplifier 26 and recorded on the magnetic tape by the video signal recording/reproducing head 27.

On the other hand, the noise of the audio signal input from the audio signal input terminal 41 is reduced by the noise reduction/audio signal amplification circuit 42, the audio signal is amplified, and then sent to the modulation circuit 43. The signal modulated by the modulation circuit 43 is amplified by a recording amplifier 44 and recorded on a magnetic tape by a high-fidelity audio signal recording/reproducing head 45.

Both the video signal recording and reproducing head 27 and the high-fidelity audio signal recording and reproducing head 45 are mounted at a predetermined position on the cylinder.
Since K is fixed, the video signal and audio signal are overwritten.

Next, when performing an index search, first the index signal is detected while the tape is in fast forward mode.

When the index signal is detected, the tape is loaded and fast-forward playback begins.

When fast-forward playback is started, the video signal recording and reproducing head 27 and the high-fidelity audio signal recording and reproducing head 45
The video signal and audio signal are read out. The video signal output from the video signal recording/playback head 27 is sent to the playback amplifier 28.
and then demodulated by the demodulation circuit 29. The demodulated signal is sent to a video signal output amplifier 31 and a video signal presence/absence detection circuit 30. The video signal output amplifier 31 amplifies the demodulated signal and connects it to the video signal input terminal 32.
Output through . On the other hand, the video signal presence detection circuit 30 detects the presence or absence of a video signal. Since we are now assuming that a video signal exists, the video signal presence/absence detection circuit 3
0 sends a signal indicating the presence of a video signal to the system control circuit 6.

When the system control circuit 6 receives a signal from the video signal presence detection circuit 30, it sends a signal to the audio signal muting circuit 48 to mute the audio signal.

Therefore, the audio signal reproduced by the high-fidelity audio signal recording/reproducing head 45 is not sent to the audio signal output amplifier 49.

Therefore, no audio signal is output from the audio signal output terminal 50, and no audio can be heard.

The above operation was the operation when both the video signal and the audio signal were recorded on tape and then played back.Next, in this embodiment, only the audio signal is recorded, and then played back in high-fidelity. Explain the operation when

When recording only audio signals in high-fidelity, an index signal is first recorded on the tape in the same manner as described above. Next, an audio signal is input from the audio signal input terminal 41, but no video signal is input from the video signal input terminal 21 (white noise is input). Therefore, the video signal presence/absence detection circuit 23 outputs a signal with no video signal.

Therefore, the switching circuit 24 is connected to the video dump circuit 2.
By grounding the output of 2, etc., the video signal is grounded.

As a result, a constant unmodulated sine wave signal is output from the modulation circuit 25, and is recorded on the tape by the video signal recording/reproducing head 27. On the other hand, the audio signal input from the audio signal input terminal 41 is overwritten on the tape in the same manner as described above.

Next, when performing an index search on a tape on which only such audio signals are recorded, the following operations are performed.

First, as described above, an index signal is detected by the index signal detection device 4 in the fast forward state. When the index signal is detected by the index signal detection device 4 and inputted to the system control circuit 6 via the index signal amplification and shaping circuit 5, the system control circuit 6 sends a control signal to a loading mechanism (not shown) to load the tape. Load. Then, fast-forward playback begins.

By fast-forward reproduction, the video signal recording/reproducing head 27 reproduces the video signal on the tape, but since no video signal is recorded, the output of the demodulation circuit 29 becomes a constant DC voltage. The video signal presence/absence detection circuit 30 thereby determines that no video signal is recorded on the tape, and outputs a signal indicating no video signal to the system control circuit 6.

When the system control circuit 6 receives the signal without the video signal, it outputs a control signal for normal reproduction to the drive device 7. Accordingly, the capstan and reel rotate in the normal playback direction and rotation speed.

The system control circuit 6 also sends a signal to the audio signal muting circuit 48 to prohibit the audio signal 1 muting circuit 48 from muting the audio signal.

For this reason, the nine-eye audio reproduced by the hi-fi audio signal recording and reproducing head 45 is amplified by the reproduction amplifier 46, demodulated by the demodulation circuit 47, and then passed through the audio signal muting circuit 48 to the audio signal output amplifier 49. sent to. The signal is then amplified by the audio signal output amplifier 49 and output from the audio signal output terminal 50.

Therefore, the operator can hear the beginning of the song recorded in high-fidelity on the tape.

Then, if the cued song is the desired one, playback of the song continues. On the other hand, if it is not the desired song, the index search function is selected again and the same operation as above is repeated.

Next, the index search function of the system control circuit 6 at the time of index search will be explained with reference to chart 70 in FIG.

Step S1...The operator determines whether the index search function has been selected. If YES, proceed to step S2.

Step S2... Fast-forward (FF) the magnetic tape in the unloaded state.

Step S3: It is determined whether an index signal is detected. When the index signal is detected, the process advances to step S4.

Step S4: Loading the magnetic tape.

Step section: Next, a command is given for fast-forward playback.

Step portion: It is determined whether a signal with a video signal or a signal without a video signal has been input from the video signal presence/absence detection circuit 30. When a signal with a video signal is input, the process advances to step S7, and when a signal without a video signal is input, the process advances to step S88.

Step S7...Mute the audio signal.

Step 8: Prohibit muting of the audio signal and output audio.

Step section: Issues commands for normal playback.

As described above, according to this embodiment, even when only audio is recorded in high-fidelity on a tape, music selection can be performed by index search.

(Effects of the Invention) According to the present invention, even when only the audio code is recorded in high-fidelity on the tape, it is possible to select songs by index search, so it is possible to select songs in the same way as with conventional audio decks. It has the effect of being able to.

In addition, the present invention can be implemented simply by adding a few circuits to the conventional 6VTRK having the function of index searching video signals, that is, by adding a video signal presence/absence detection circuit, so it can be easily and inexpensively manufactured. be able to.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a basic configuration diagram of a conventional VTR with an index search function,
FIG. 3 is a block diagram showing a specific example of a video signal presence/absence detection circuit, and FIG. 4 is a flowchart showing the functions of the system control circuit shown in FIG. 1. DESCRIPTION OF SYMBOLS 1... Index signal input terminal, 2... Index signal recording circuit, 3... Index signal recording head, 4... Index signal detection device, 6... System control circuit, 7... G movement aw, 21...
Video 4JR signal input terminal, 22...Video 2 ring circuit,
23.30... Video signal presence detection circuit, 24... Switching circuit, 25... Modulation circuit, 26... Recording amplifier, 27... Video signal recording/reproducing head, 28...
- Reproduction amplifier, 29... Demodulation circuit, 31... Video signal output amplifier, 32... Video signal output terminal, 41...
-Audio signal input terminal, 42...Noise reduction/audio signal amplification circuit, 43...Modulation circuit, 45...Audio signal recording/playback head for hi-fi, 48...Audio signal mini-
Teing circuit diagram 1 η

Claims (1)

[Claims] (1) When an index signal recorded on a magnetic tape is detected, the video signal is recorded in a high-fidelity magnetic recording and reproducing device (hereinafter abbreviated as high-fidelity VTR) that has an index search function that loads the magnetic tape and performs fast-forward playback. A means for determining whether or not there is a video signal in the signal reproduced by the reproducing head, and outputting a control signal for normal reproduction when there is no video signal, and a means for determining whether or not there is a video signal in the signal reproduced by the hi-fi audio recording and reproducing head. 1. A high-fidelity VTR comprising means for outputting a signal for inhibiting muting of audio signals, and means for inhibiting muting of high-fidelity audio when the inhibition signal is input.