JPS644399B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A conventional microphone device includes, in a microphone case, a vibration-to-electrical converter for obtaining an analog electrical signal proportional to the mechanical vibration generated in a diaphragm or diaphragm by a sound wave, and It houses an amplifier that amplifies the analog electrical signal from the electrical converter, and has a structure in which the analog signal is extracted as a microphone output.

However, such conventional microphone devices have drawbacks such as deterioration of high-frequency components and mixing of noise when the cable from the microphone device becomes long.

Even with wireless microphone devices that modulate radio waves of a suitable frequency with analog electrical signals from a vibro-electrical converter and transmit the modulated waves, they still have drawbacks such as noise being mixed in due to the strength of the electric field.

A novel microphone device that eliminates these drawbacks and inconveniences will be described below with reference to the examples shown in FIGS. 1 to 5.

The microphone device shown in FIG.
The case houses an amplifier 3 that amplifies the analog electrical signal from the electrical converter 2, and an A-D converter 4 that converts the analog electrical signal passed through the amplifier 3 into a digital electrical signal. A cable 6 is led to the outside of the microphone 1, and a digital electric signal is output by wire as a microphone output.

Here, as the A-D conversion in the A-D converter 4, methods such as pulse width modulation (PWM), pulse position modulation (PPM), pulse number modulation (PNM), and pulse code modulation (PCM) may be used. I can do it.
Among these, pulse code modulation is particularly suitable.

In addition to the configuration shown in FIG. 1, the microphone device shown in FIG. 2 further includes an A-
It houses a high frequency modulation section 5 that amplitude modulates or frequency modulates a higher frequency carrier wave using the digital electrical signal from the D converter 4, and leads a cable 6 from the high frequency modulation section 5 to the outside of the case 1 to conduct high frequency modulation. It is configured so that a digital electrical signal is transmitted via wire as a microphone output.

In this case, a spread spectrum method may be used instead of amplitude modulation or frequency modulation.

The microphone device shown in FIG. 3 is configured as a wireless microphone device, and in addition to the configuration shown in FIG.
It is constructed by housing a high frequency output section 7 that wirelessly transmits digital electrical signals from. In this case, the digital electrical signal may be transmitted directly from the A-D converter 4 without being modulated, or it may be modulated and transmitted as described above.

In addition to the configuration shown in FIG. 1, the microphone device shown in FIG. 4 houses an electro-optical converter 8 for converting a digital electrical signal from an A-D converter 4 into a digital optical signal in the microphone case 1, An optical fiber 9 is guided from the electro-optical converter 8 to the outside of the case 1, and a digital optical signal is transmitted by wire as a microphone output.

The microphone device shown in FIG. 5 is a modification of the microphone device shown in FIG. 4, and is configured to wirelessly transmit a digital optical signal from the electro-optical converter 8.

Even when transmitting a digital electrical signal as an optical signal, as in the example shown in FIGS. 4 and 5, a higher frequency carrier wave is amplitude-modulated or frequency-modulated with the digital electrical signal from the A-D converter 4, The modulated digital electrical signal may be converted into an optical signal by the electro-optical converter 8 and then transmitted.

According to the microphone device shown in FIGS. 1 to 5 described above, a vibration-electrical converter, an amplifier that amplifies the output of the vibration-electric converter, and an analog output signal from the amplifier are converted into a digital signal. A
- D converter is housed inside the microphone case, so compared to analog signal transmission, there is no risk of signal deterioration, noise incorporation, interference, or leakage of the acoustic signal to the outside, and the acoustic signal can be enhanced. It can be transmitted with high quality and high fidelity.

The present invention is an improvement on such a microphone device, and compared to analog signal transmission, there is no risk of signal deterioration, noise mixing, interference, or leakage of acoustic signals to the outside, and the acoustic signals can be transmitted with high quality and high quality. The present invention aims to propose a microphone device that can transmit data with high fidelity, has a simple configuration, and can be easily controlled from the outside depending on the usage situation.

Embodiments of the present invention will be described in detail below with reference to the drawings. First, with reference to FIG. 6, an embodiment will be described in which a plurality of microphones are used simultaneously as wired microphone devices.
M ₁ , M ₂ and M ₃ are microphone devices having the same configuration as shown in FIG. 1, and are microphone devices for channels 1, 2 and 3, respectively. Then, a clock CK with a marker signal MK as shown in the lower part of FIG _.
The analog signals passed through the amplifiers ₃ are converted into digital signals, in this case n-bit PCM signals. Signal MK
After that, the 1st bit of channel 1, channel 2
The first bit of channel 3, the second bit of channel 1, the n-th bit of channel 2, the n-th bit of channel 3, and so on are supplied to the adder section of the repeater 30 and multiplexed at the following timing. Then, the time-division multiplexed signal from the adder of the repeater 30 is supplied to the receiver 40, and the clock CK with the marker signal MK from the clock generator is supplied to the receiver 40 to demodulate each channel. Get a signal.

Incidentally, in this embodiment, each of the microphone devices M ₁ to _{M 3} has a cable for receiving the clock from the repeater 30 and a cable for connecting the microphone output to the repeater 3.
You will need two cables, one for sending to 0.

In consideration of this point, FIG. 7 shows an embodiment in which clock transmission and reception and microphone output transmission and reception can be performed using a single cable. That is, the microphone devices for channels 1, 2, and 3
M ₁ , M ₂ , and M ₃ have the configuration of the microphone device shown in FIG. 2, with a clock separation circuit 21 added thereto. In this case, a crystal oscillator or the like is used as the oscillator in the high frequency modulation section 5 of the microphone devices _M1 to _M3 of each channel, so that the frequency of the carrier wave modulated by the digital signal from the A-D converter 4 is stable and Make sure the channels are the same. And each microphone device M ₁ ~
_M3 has a clock separation circuit 21 inside the case.
microphone devices M ₁ to _{M 3} from the repeater 30 through a cable that houses the microphones and sends the microphone output.
A clock is sent to the microphone output, and a clock separation circuit 21 separates the clock using the difference in frequency from the microphone output, and supplies the clock to the AD converter 4. The time division multiplexed signal and clock are also sent from the repeater 30 to the receiver 40 via one cable.

In all of the above embodiments, a clock is sent from a repeater to each microphone device, but time division multiplex transmission can also be performed by generating a clock within each microphone device without sending a clock from a repeater. It is possible.

FIG. 9 shows an embodiment in which a plurality of wireless microphone devices are used simultaneously, in which a clock with a marker signal is transmitted from the fixed station 50 and received by each of the microphone devices M ₁ to _{M 3} making up the mobile station. ,
Signals are transmitted from each of the microphone devices M ₁ to _{M 3} at timings that are time-division multiplexed, and the signals are received and demodulated by the fixed station 50. In this case, the signals from the microphone devices M ₁ to _{M 3} are each a digital signal from an A-D converter, and are transmitted after amplitude modulating or frequency modulating a carrier wave of a certain higher frequency ₁ . The clock modulates the amplitude or frequency of another frequency ₂ carrier wave and transmits it. However, it is also possible to use carrier waves of the same frequency by using different modulation methods.

Note that various combinations of light and the like can be used in addition to radio waves as the electromagnetic waves between the fixed station and each wireless microphone device. Further, an electromagnetic induction method may also be used.

FIG. 10 shows a case in which the electromagnetic induction method is also used, in which a wire 60 for clock transmission by the electromagnetic induction method is run from a fixed station 50, and a current is passed through it to generate a magnetic field. Since the magnetic field decreases in inverse proportion to the cube of the distance, the service area can be limited.

According to the present invention described above, a vibration-electric converter, an amplifier that amplifies the output of the vibration-electric converter, and an A-D converter that converts an analog output signal from the amplifier into a digital signal are connected to a microphone. Since the A-D converter is installed inside the case and the operation of the A-D converter is controlled from the outside, there is less risk of signal deterioration, noise, interference, and leakage of acoustic signals to the outside than with analog signal transmission. It is possible to transmit acoustic signals with high quality and high fidelity, and multiplex transmission is possible, so it is possible to effectively utilize the band when using multiple microphone devices and reduce the number of cable relays used. It is possible to obtain a microphone device that is possible, has a simple configuration, and can be easily controlled from the outside depending on the usage situation.

In addition, since the amplifier is a variable gain type amplifier, there is no need to control its gain externally, and the gain of the transmitted acoustic signal can be easily varied by controlling the A-D converter, which prevents errors during sound collection. There is no risk of changing the gain of the amplifier.

Furthermore, for example, only necessary microphone devices among a plurality of microphone devices can be made operable by supplying a control signal (clock signal) from the outside. Furthermore, by varying the frequency of the clock signal supplied to the A-D converter on the control device side, the A-D
Since the sampling period of the D converter can be varied, remote control according to the situation in which the microphone device is used becomes possible.

Incidentally, it is also possible to supply the digital signal output from the microphone device to the control device side and vary the sampling frequency again on the control device side, but it is also possible to supply the digital signal output from the microphone device to the control device side. However, according to the present invention, it is necessary to convert the signal into an analog signal using a D-A converter, and then process it using an A-D converter with a predetermined sampling frequency, which complicates the processing on the control device side. Since it is only necessary to control the A-D converter in the microphone device, processing on the control device side is also simplified.

[Brief explanation of drawings]

1 to 5 are block diagrams showing examples of microphone devices applicable to the present invention, FIG. 6 is a block diagram showing one embodiment of the present invention, and FIG. 7 is a block diagram showing other examples of microphone devices of the present invention. FIG. 8 is a waveform diagram for explaining the embodiment of the present invention, FIG. 9 is a block diagram showing another embodiment of the present invention, and FIG. 10 is a diagram showing still another embodiment of the present invention. FIG. 6 is a block diagram showing another embodiment. 1 is a microphone case, 2 is a vibration-electric converter, 3 is an amplifier, and 4 is an A-D converter.

Claims (1)

[Claims] 1. A vibration-electrical converter, an amplifier that amplifies the output of the vibration-electrical converter, and an A-D converter that converts an analog output signal from the amplifier into a digital signal in a microphone case. What is claimed is: 1. A microphone device, characterized in that the A-D converter is provided in the microphone, and the operation of the A-D converter is controlled from the outside.