JPS6262679A - Dubbing device - Google Patents

Abstract

PURPOSE:To perform dubbing of a sound signal without deteriorating S/N by a simple circuit constitution by directly recording a sound RF signal reproduced from a magnetic disk on other magnetic disk without converting into an original sound signal. CONSTITUTION:A reproducing side 20 has a magnetic disk 7a on which a sound signal is recorded, a head 6a and a reproducing amplifier 8a. By the head 6a, a sound RF signal recorded on the magnetic disk 7a is reproduced, amplifier by the reproducing amplifier 8a and thereafter supplied to an output terminal 21 for dubbing. A recording side 30 has an input terminal 22 for dubbing and the reproducing sound RF signal from the reproducing side 20 obtained from the input terminal 22 is connected to one change over terminal a of a change over switch 24, passed through a recording amplifier 5b under the change over switch 24 changed over to the change over terminal a and the sound RF signal obtained from the reproducing side 20 is directly recorded on other magnetic disk 7b by a head 6b.

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to a dubbing device for an electronic camera system that records and reproduces video signals, audio signals, and data signals on a magnetic disk. The present invention relates to a dubbing device for reproducing and recording on another magnetic disk.

(Background of the invention) In recent years, electronic camera systems have been developed that use 50 tracks of one magnetic disk to record and reproduce video signals (field recording uses 1 track, frame recording uses 2 tracks), audio signals, and data signals. is proposed.

FIG. 3 is a block diagram showing an audio signal recording and reproducing device in such an electronic camera system.

First, to record an audio signal, an audio signal input from a microphone or the like is level-compressed in a noise reduction circuit 1 and then supplied to a time compression circuit 2. The time compression circuit 2 first performs AD conversion on the audio signal and writes the digitized audio signal into the -H memory. Subsequently, when reading the digital audio signal from the memory, a faster clock than when writing is used for reading and DA conversion, thereby obtaining a temporally compressed audio signal. This compressed audio signal is supplied to the audio data addition circuit 3, where ID pulses indicating the start and end of each 1/4 field (the polarity is positive or negative) and audio data indicating the correspondence with the video recording track are added. . Specifically, as shown in FIG.
1. Audio data 22, audio compressed signal 23 and end ID
They are arranged in the order of 24 to generate a signal that is repeated every 1/4 field.

The audio compressed signal to which the ID pulse and audio data have been added is subjected to pre-emphasis in the FM modulation circuit 4, then FM modulated, and converted into an audio RF multiplied signal which passes through the recording amplifier 5 and is transferred to the magnetic disk by the head 6. recorded.

On the other hand, to reproduce the audio signal recorded on the magnetic disk 7, the audio signal reproduced from the magnetic disk 7 through the head is amplified by an RF signal reproduction amplifier 8, and then an FM demodulation circuit 9 is used to reproduce the RF signal.
M demodulates and applies de-emphasis. The reproduced audio compressed signal from the FM demodulation circuit 9 is expanded to the original time by a time expansion circuit 10 which performs processing opposite to that of the time compression circuit 2.

The reproduced audio signal returned to its original state by this time expansion is subjected to level expansion in a noise reduction circuit 11 to have a characteristic opposite to that at the time of recording, and is outputted from a speaker 12 or the like.

Now, when dubbing is performed by reproducing an audio signal recorded on a magnetic disk and recording it on another magnetic disk using such an audio signal recording/reproducing device, the reproduction side shown in Fig. 2 is used. Noise reduction circuit 11 to 1q
By connecting the output of the recorded audio signal to the audio signal input of another recording device, dubbing of the audio signal can be performed.

(Problems to be Solved by the Invention) However, in a dubbing device that uses such conventional playback circuits and recording circuits as they are, the RF-multiplied audio signal reproduced from the magnetic disk is once converted into the original audio signal. After conversion, the audio RF signal is converted and recorded again, so the conversion of the RF signal is doubled, and the RF signal is converted back to the original signal, and then the RF signal and the individual signals are converted. There was a frequent problem that the S/N ratio deteriorated due to the processing.

(Object of the Invention) The present invention has been made in view of the above-mentioned conventional problems, and is an object of the present invention to enable dubbing of audio signals with a simple circuit configuration without causing deterioration of the S/N ratio, etc. The purpose of the present invention is to provide a dubbing device that has the following features.

(Summary of the invention) In order to achieve this object, the present invention records an RF multiplied audio signal reproduced from a magnetic disk on another magnetic disk as it is without converting it into the original audio signal. It is.

(Example) FIG. 1 is a block diagram showing one embodiment of the present invention.

First, the playback side 20 will be explained. It is equipped with a magnetic disk 7a on which an audio signal is recorded, a head 6a, and a playback amplifier 8a. The head 6a plays back the audio RF multiplied signal recorded on the magnetic disk 7a, and the playback amplifier 8a amplifies it. After that, it is supplied to the output terminal 21 for dubbing.

On the other hand, the recording side 30 is provided with an input terminal 22 for dubbing, and one switching terminal a of the reproduction audio RF multiplied signal changeover switch 24 from the reproduction side 20 obtained from the input terminal 22
, and with the changeover switch 24 switched to the changeover terminal a side, the audio RF multiplied signal obtained from the playback side 20 is recorded as it is on another magnetic disk 7b by the head 6b through the recording amplifier 5b. .

Further, the recording side 30 is provided with an FM demodulation circuit 9b that inputs the reproduced RF signal from the input terminal 22 for dubbing.
The reproduced RF signal is FM demodulated and de-emphasized before being supplied to the data rewriting circuit 23. This data rewriting circuit 23 is used to rewrite audio data during dubbing.

The audio signal whose audio data has been changed by the data rewriting circuit 23, that is, the audio signal having the arrangement shown in the signal waveform of FIG.
The signal is FM-modulated again at b and is supplied to the other switching terminal of the changeover switch 24.

Therefore, by switching the changeover switch 24 to the changeover terminal 24 side when changing the audio data, the data rewriting circuit 23
The audio FM signal containing the changed audio data is selected and recorded on the magnetic disk 7b by the head 6b through the recording amplifier 5b. In addition, when the audio data does not need to be changed, by switching the changeover switch 24 to the switching terminal a side, the audio RF multiplied signal obtained from the playback side 20 is recorded as is on the magnetic disk 7b. .

Next, to explain the operation of the embodiment shown in FIG. 1, first, the reproduction side 20 only needs a reproduction amplifier 8a that amplifies the audio RF signal from the magnetic disk 7a reproduced by the head 6a.
In addition, if there is no need to change the audio data on the recording side 30, it is sufficient to use only the recording amplifier 5b, and the circuit configuration of the playback side 20 and the recording side 30 for dubbing is the same as that shown in FIG. It is greatly simplified compared to the case where the recording circuit and the audio reproduction circuit are used as they are, and it is possible to convert the reproduced audio RF multiplied signal into the original audio signal, and further convert the original audio signal back into the audio RF multiplied signal. Since no processing is required, S/S of the audio signal by dubbing is
Deterioration of the N ratio can be suppressed to a minimum.

Also, when it is necessary to change the audio data during dubbing, the changeover switch 24 provided on the recording side 30 allows
Audio data can be easily changed by selecting the signal processing system of the M demodulation circuit 9b, the data rewriting circuit 23, and the FM modulation circuit 4b.

Regarding this change in audio data, since the data is rewritten after the reproduced audio RF multiplied signal is FM demodulated, as shown in Figure 3, after FM demodulation, time expansion and noise reduction signal processing is performed, and then the audio Compared to the case where data is rewritten, the signal processing process is simplified and the deterioration of the S/N ratio can be kept to a minimum.

FIG. 2 is a block diagram showing another embodiment of the invention. In the embodiment shown in FIG. 1, the circuit configuration is dedicated to dubbing devices on the reproduction side and recording side, but in this embodiment, as shown in FIG. The dubbing device of the present invention is aimed at a device provided with a circuit and an audio reproduction circuit, and is characterized in that the dubbing device of the present invention is realized by using a part of the audio recording and reproduction circuit.

That is, the playback side 20 is equipped with a magnetic disk 7a, a head 6a, and a playback amplifier 8a as in the embodiment shown in FIG. supplying.

On the recording side 30, the audio recording circuit and audio reproducing circuit shown in FIG. 3 are provided as they are, and the same parts are designated by the same numbers as in FIG. 3.

On such a recording side 30, in order to realize the function as a dubbing device of the present invention, a changeover switch 32 is provided to change the connection between the output of the reproduction amplifier 8 and the input terminal 22 for dubbing. A changeover switch 36 is provided for supplying the reproduced RF signal to the FM demodulation circuit 9 or the recording amplifier 5. On the input side of the recording amplifier 5, a changeover switch 34 is provided to change over the signal from the changeover switch 36 and the signal from the FM modulation circuit 4.

Furthermore, in order to make it possible to rewrite the audio data, FMif
The output of the i-key circuit 9 is sent to a time expansion circuit 10. Alternatively, a changeover switch 38 is provided for supplying audio data to the audio data addition circuit 3 via the changeover switch 40.

To explain the operation of the embodiment shown in FIG. 2, when dubbing does not require changing the audio data, the selector switch 32 on the recording side 30 is switched to the switching terminal side. Also, the changeover switch 36 is switched to the changeover terminal a side. Furthermore, by switching the changeover switch 34 to the switching terminal side, the playback side 2
A signal processing loop for dubbing is formed in which the reproduced audio RF multiplied signal obtained from 0 is directly supplied to the head 6 via the recording amplifier 5.

On the other hand, when it is necessary to change the audio data, the changeover switch 32 is switched to the changeover terminal side, and the changeover switch 36 is similarly switched to the changeover terminal side. Further, the selector switch 38 is switched to the a side, and the selector switch 40 is switched to the select terminal side. In addition, by switching the changeover switch 34 to the switching terminal a side, the reproduced RF signal from the reproduction side 20 is transferred to the FM demodulation circuit 9, the audio data addition circuit 3, and the F
forming a signal processing loop for changing audio data supplied to the head 6 through the M modulation circuit 4 and the recording amplifier 5;
The audio data adding circuit 3 changes the audio data to be dubbed.

Even in the embodiment shown in FIG. 2, if the audio data does not need to be changed, the reproduced audio RF signal from the reproducing side 20 is directly sent to the recording side and recorded. FM pre-installed on the recording side 30
The 1W tone circuit 9 and the audio data addition circuit 3 are used for dubbing, which makes the signal processing simpler than when dubbing is performed using the conventional recording/reproducing circuit shown in Fig. 3. , the deterioration of the S/N ratio can be minimized, and the circuit configuration of the dubbing device itself can be simplified.

(Effects of the Invention) As described above, according to the present invention, the audio RF multiplied signal reproduced from the magnetic disk is recorded on another magnetic disk as it is without converting it to the original audio signal. There is no need to perform individual signal@processing such as demodulating the reproduced audio RF multiplied signal by FM, then returning it to the original audio signal through predetermined signal processing, and then performing FM modulation using reverse signal processing before recording. Therefore, the circuit configuration for dubbing is simplified, and there is no signal conversion process, so dubbing can be performed with the deterioration of the S/N ratio kept to a minimum.

In the embodiment of the present invention, when it is necessary to change the audio data during dubbing, the reproduced audio RF multiplied signal F
Data is rewritten in the state of M demodulation, and once the data has been rewritten, it is FM modulated again and recorded on another magnetic disk, so signal conversion is done by FM demodulation and F
Only M modulation is required, and when it comes to data rewriting, compared to the case where conventional recording and reproducing circuits are used as they are, individual signal processing can be reduced and deterioration of the S/N ratio can be kept to a minimum.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram showing a second embodiment of the invention, and Fig. 3 is a block diagram showing an example of a conventional recording and reproducing circuit. , 4th
FIG. i is a signal waveform diagram showing the arrangement of signals obtained from the data addition circuit of FIG. 3. 1: Noise reduction circuit (level compression) 2: Time compression circuit 3: Audio data addition circuit 4.4b: FM modulation circuit 5.5b: Recording amplifier 6.6a, 5b: Head 7.7a, 7b: Magnetic disk 8. 88: Playback amplifier 9.9b: FM demodulation circuit 10: Time expansion circuit 11: Noise reduction circuit (level expansion) 12: Speaker 20: Playback side 30: Recording side 21: Output terminal for dubbing 22: Input terminal for dubbing

Claims (1)

[Claims] Dahobing characterized by comprising a reproduction means for reproducing and outputting an audio RF signal recorded on a magnetic disk, and a recording means for recording the audio RF signal outputted from the reproduction means as it is on another magnetic disk. Device