JPH01218186A - Recorder - Google Patents

Abstract

PURPOSE:To obtain a video recording signal of less deterioration in resolution and picture-quality without disturbing an audio signal by varying the attenuation amount of an attenuating filter for video signal in a certain frequency band corresponding to that of an audio recording signal corresponding to the level in said frequency band. CONSTITUTION:The component in a frequency band where an FM-modulated audio signal in a video recording signal mixed in a mixing circuit 8 is disturbed is taken out by a band-pass filter 10, amplified, then detected by a detection circuit 12 in order to make it a control signal. From the output of the circuit 12, a voltage corresponding to the component of the frequency band giving the disturbance to the audio signal is supplied to the control terminal 21 of a variable filter 9. As this voltage is boosted, the conductivity between the collector and the emitter of the transistor of a variable tracp circuit 22 is increased, so that the amount of the attenuation on the output of video signal in the frequency band where FM-modulated audio signal inputted from the terminal 20 is disturbed becomes larger. As a result, deterioration in the resolution and the picture-quality of a video can be suppressed without disturbing an audio recording signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording device that frequency-multiplexes audio signals and video signals and records them on a recording medium.

[Prior Art] Fig. 5 shows a so-called high-speed device which frequency modulates an audio signal, frequency multiplexes it with a video signal, and records it on a recording medium.
FIG. 2 is a diagram showing a spectrum distribution of a recording signal in a phi-VTR. In the figure, Y indicates an FM-modulated luminance signal, A indicates an FM-modulated audio signal, and C indicates a spectrum of a carrier color signal whose carrier wave is converted to a low frequency band.

Fig. 2 is a block diagram showing the general configuration of a conventional high-fidelity VTR, in which l is an audio signal, 2 is a terminal for inputting a video signal, and 3 is an audio signal that performs processing such as FM (frequency) modulation on the audio signal. Signal processing circuits 4 and 5 are used to separate the video signal input from terminal 2 into a luminance signal and a color signal;
P, F and B, P, F, 6 and 7 are a luminance signal processing circuit and a color signal processing circuit that process the separated signals, 16 and 17 are filters, 18 is an FM modulated audio signal, A mixing circuit mixes the FM modulated luminance signal and the low frequency converted color signal, 14 is a recording amplifier that amplifies the signal from this mixing circuit 18, and 15 is a magnetic head.

In the recording device shown in FIG. 2, video signals such as an FM modulated luminance signal and a low frequency converted color signal from a luminance signal processing circuit 6 and a color signal processing circuit 7 are transmitted to an FM modulated signal from an audio signal processing circuit 3.
A filter 1 that attenuates the band of the FM modulated audio signal of the video signal after signal processing so as not to interfere with the modulated audio signal.
6 and 17 are inserted.

[Problem to be Solved by the Invention] However, in a conventional device having a band attenuation filter for this type of video signal, even a video recording signal that does not interfere with the audio FM signal is subjected to video signal processing. After that, this band attenuation filter is always inserted, and there is a problem in that passing the image through this filter causes deterioration in resolution and image quality.

The present invention has been made to solve such problems, and an object of the present invention is to provide a recording device that can obtain a video recording signal without interfering with the audio signal and with less deterioration in resolution and image quality. do.

[Means for Solving the Problems] In order to achieve the above object, the recording device of the present invention adjusts the level of a predetermined band corresponding to the band of an audio recording signal in a video recording signal. It has a configuration that changes the amount of attenuation of the attenuation filter of the video signal.

[Function] By having the configuration described above, the filter characteristic in the case of video that does not interfere with the audio recording signal can be set to the minimum necessary attenuation amount, and it is possible to improve the image quality of the video signal.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the recording apparatus according to the present invention, in which 8 is a mixing circuit for mixing a luminance signal and a color signal;
10 is a bandpass filter (B, P, F) that passes only the band that interferes with the audio FM signal; 11 is an amplifier;
12 is a detection circuit, 9 is a variable filter for the audio FM signal band, and 13 is a mixing circuit for mixing the audio signal and the video signal. Further, the same reference numerals as in FIG. 2 indicate the same or corresponding parts.

In FIG. 1, an audio signal input from an audio signal input terminal l is converted into an FM signal by an audio signal processing circuit 3, and mixed with a video recording signal by a mixing circuit 13. Video signal beams input from video signal input terminal 2, P, F
4, B, P, and F5 into a luminance signal and a chrominance signal, each of which is converted into a recording signal by a luminance signal processing circuit 6 and a chrominance signal processing circuit 7 as described above, and mixed by a mixing circuit 8. B, P, and FIO extract band components that cause interference to the mixed video recording signal and medium-wave FM modulation audio signal.
A detection circuit 12 is used to amplify the control signal.
Perform wave detection. The output of the detection circuit 12 is input to the control terminal of the variable filter 9 as a voltage corresponding to a component in a band that interferes with the audio signal.

FIG. 4 is a characteristic curve diagram of the variable filter 9 of FIG. 1.

If the recorded video signal from the mixing circuit 8 in FIG. 1 has few components that interfere with the FM modulated audio signal, the filter characteristics in FIG. This prevents deterioration in resolution and image quality. Furthermore, as the number of components that interfere with the FM modulated audio signal increases, the filter characteristic becomes F. Changes like →F, →F2.

A video recording signal that does not affect the audio FM band is always sent to the mixing circuit 13. Note that the signal input to the terminal 2 to which the video signal is input may be a television signal from a tuner or a signal from a video camera.

FIG. 3 is a circuit diagram showing a specific example of the variable filter 9 in FIG. , 22 is a variable trap circuit, 23
24 is a buffer, and 24 is an output terminal. A voltage corresponding to a component in a band that interferes with the FM modulated audio signal is inputted to a terminal 21 of the variable filter 9 shown in FIG. As this voltage increases, the conductivity between the collector and emitter of the transistor of the variable trap circuit 22 increases.

The output of the video signal in the band that interferes with the FM modulated audio signal input from the terminal 20 has a large amount of attenuation. Conversely, when there are few band components that cause interference to the FM modulated audio signal, the transistor of the trap circuit 22 is in a non-conducting state.

The video signal input from the terminal 20 is not attenuated,
It is output from the terminal 24.

In the above-described embodiment, the block diagram and spectrum diagram are for the case where the audio signal is monaural, or the same effect can be obtained even in the case of a stereo high-fidelity VTR having two or more audio FM carriers.

In addition, in the above-mentioned embodiment, the variable filter is inserted after processing and mixing the luminance signal and the nine color signals, but independent variable filters are set for each of the luminance recording signal and the nine color recording signals. A similar effect can be obtained by mixing after passing.

[Effects of the Invention] As explained above, the present invention changes the amount of attenuation of the attenuation filter of the band corresponding to the band of the audio recording signal in accordance with the level of the band that interferes with the audio recording signal in the recorded video signal. By doing so, it is possible to suppress the deterioration of the resolution and image quality of the video without interfering with the audio recording signal, and it is possible to realize a recording device that does not interfere with the audio regardless of the video signal.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the recording device according to the present invention, FIG. 2 is a block diagram of a conventional recording device such as a high-fidelity VTR, and FIG. 3 is a specific example of the variable filter in FIG. 1. 4 is a characteristic curve diagram of the variable filter 9 of FIG. 1, and FIG. 5 is a circuit diagram showing frequency modulation of an audio signal.
FIG. 3 is a diagram showing the spectrum distribution of each recording signal when multiplexed with a video signal and recorded on a recording medium. In the figure. l, 2: terminal 3: audio signal processing circuit 4, P, F 5.10: B, P, F 6: luminance signal processing circuit 7: color signal processing circuit 8, 13.18: i combining circuit 9: Audio FM band variable filter 11: Amplification circuit 12: Detection circuit 14: Recording amplifier 15: Magnetic head 16.17: Attenuating filter Agent Patent attorney 1) Haru Kitatake Figure 1 Figure 2

Claims (1)

[Claims] In a recording device that frequency multiplexes an audio signal and a video signal and records them on a recording medium, the video recording signal in a predetermined band is attenuated according to the level of the predetermined band corresponding to the band of the audio recording signal in the video recording signal. A recording device characterized in that the amount of attenuation of a filter is varied.