JPH0743808Y2 - Wireless voice recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a wireless voice recording device.

(B) Conventional technology In Japanese Patent Laid-Open No. 61-32686 (H04N9 / 04), video signals, audio signals, etc. are converted into broadcast wave format, output from a camera, and received by a VTR tuner. The configuration of recording is shown. By the way, the audio system has an FM modulator on the transmitting side,
An FM demodulator is arranged on the receiving side, and the transmitted signal is once restored to the original audio signal and then processed for recording.

(C) Problems to be solved by the invention By the way, there are cases where it is desired to record only audio signals in a wireless format. For example, at a meeting or a wedding, it is conceivable that a separately prepared microphone is used for audio and a video camera is used for video (the microphone attached to the video camera is not used). or,
By recording the location away from the camera by increasing the focal length of the lens for the image, and by arranging the wireless microphone close to the audio, it is possible to record the image of the wildlife relatively. It can be easily achieved.

It is desirable for such a device to be as simple in construction as possible.

(D) Means for solving the problem In the present invention, the audio signal is encoded by the noise reduction circuit and then FM-modulated, and the FM audio signal is frequency-converted on the VTR side and recorded on the tape. .

(E) Action Therefore, the FM demodulation circuit is unnecessary on the receiving VTR side, and the configuration is simple.

(F) Example An example in which the present invention is applied to an 8 mm VTR will be described below with reference to the drawings. FIG. 1 is a block diagram showing a transmitting device, and FIG. 2 is a block diagram showing a main part of a VTR.

In FIG. 1, (1) is a microphone for collecting sound, (2) is a noise reduction circuit for performing encoding processing,
(3) is an FM modulation circuit, (4) is a transmission amplifier, and (5) is a transmission antenna. The encoding characteristic of the noise reduction circuit (2) is the same as the encoding characteristic of so-called HiFi recording of the VTR, and the dynamic range is compressed with a predetermined frequency characteristic. In the FM modulation circuit (3), for example, a carrier signal of 70 to 90 MHz is FM-modulated by the output of the noise reduction circuit (2).

In FIG. 2, (6) is a receiving antenna, (7) is a high frequency amplifier, (8) is a local oscillator, (9) is a frequency converter,
(10) is a recording / playback selector switch, (11) is a bandpass filter, (12) is a limiter, (13) is an audio signal selector switch, (14) is a video signal mixing circuit, and (15) is recording. It is an amplifier. (16) is an FM demodulation circuit, (17) is a noise reduction circuit for performing decoding processing, (18) is a recording head, (19) is a reproducing head, and (20) is a magnetic tape. Although the rotary head is originally used for both recording and reproduction, it is shown as two heads for simplification of switches and the like.

The frequency converter (9) converts the frequency of the transmitted FM audio signal to a Hi-Fi VTR audio recording frequency (about 1 to 2 MHz). The bandpass filter (11) removes unnecessary components from the output of the frequency converter (9) and extracts desired components. Then, the FM audio signal of a predetermined frequency, the amplitude of which is limited by the limiter (12), is mixed with the video signal subjected to the recording process and recorded on the tape (20) by the rotary head (18). become.

The output of the limiter (12) is simultaneously FM output by the FM demodulator (16).
It is demodulated and decoded by the noise reduction circuit (17) so that recording can be monitored.

During playback, the recording / playback switch (10) is on the playback (PB) side, and the FM audio signal of the playback signal from the rotary head (19) is extracted by the bandpass filter (11) and passed through the limiter (12). The FM demodulator (16) demodulates the FM and outputs it.

The audio signal selector switch (13)
Other audio signals (which have undergone processing such as encoding and FM demodulation due to a configuration not shown) are selected.
This changeover switch is necessary for recording other than wireless voice.

With the above configuration, the voice collected by the microphone (1) is FM-modulated and transmitted, and is processed without being demodulated in the VTR. Therefore, noise reduction in FM transmission / reception is suppressed by the VTR. Can be shared with FM voice recording / playback system. Therefore, the recording system alone can greatly simplify the configuration. Further, since noise reduction processing is performed in the system of FM transmission / reception-recording / reproduction, improvement of sound quality is desired. Further, improvement in sound quality can be expected from the fact that the number of processing steps is reduced.

Note that the VTR is not limited to the 8 mm VTR, and may be of another type as long as it has an FM voice recording function.

Next, an embodiment will be described in consideration of a case where the FM signal from the transmitter does not reach the VTR for some reason.
FIG. 3 is a block diagram showing the configuration of this embodiment.

As described above, if the FM signal does not reach the VTR, that is, if there is no carrier signal, the recording operation becomes meaningless. Therefore, in the embodiment of FIG. 3, the presence or absence of the carrier signal (1.5 MHz) in the output of the limiter (12) is discriminated by the carrier detector (21), and if the carrier signal is present, the output of the limiter (12) is recorded. For example, the FM modulator (25) output is recorded (operation of the switch (22)).

The FM demodulator (25) is supplied with the signal encoded by the noise reduction circuit (24) at the output of the microphone attached to the VTR supplied to the terminal (26). Therefore, when the signal from the transmitting device is not transmitted to the VTR, the voice signal picked up by the microphone attached to the VTR is recorded, and the problem that the carrier is omitted and the voice signal is not recorded does not occur. or,
The monitor output is also switched to the terminal (26) side by the switch (23).

Further, as a solution to this problem, it is conceivable to stop the tape running and stop the recording operation when there is no carrier, or alternatively, record an unmodulated carrier signal of 1.5 MHz.

By doing so, even if it is a VTR that discriminates the presence or absence of recording by determining the presence or absence of the FM voice carrier at the time of reproduction, no malfunction occurs.

(G) Effect of the Invention As described above, according to the present invention, it is possible to realize a wireless voice recording device having a simple structure, which is practical.

[Brief description of drawings]

FIG. 1 is a block diagram showing a transmitting device, and FIG. 2 is a block diagram showing a main part of a VTR. FIG. 3 is a block diagram showing another embodiment. (1) ... Microphone, (2) ... Noise reduction circuit, (3) ... FM modulation, (6) ... Antenna, (9) ...
… Frequency converter, (20) …… tape.

Claims (1)

[Scope of utility model registration request] 1. A means for receiving a high frequency signal, wherein a voice signal is encoded by a noise reduction circuit, and a predetermined carrier signal is FM-modulated by an output signal of the noise reduction circuit, and a frequency for recording the frequency of the received FM voice signal. A wireless voice recording device comprising a frequency converter for converting into a frequency and a means for recording the frequency-converted signal.