JP2969537B2 - Digital microphone device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital microphone device used for audio equipment and the like.

[0002]

2. Description of the Related Art Conventionally, in the case of a microphone device used for this kind of audio equipment, a microphone is provided on a device body.
A coil bobbin around which a coil is wound is formed vertically and integrally on the lower surface inside the elastic diaphragm, while a permanent magnet is disposed on the device body side facing the coil bobbin, In accordance with a change in magnetic field generated when the coil bobbin vibrates in the permanent magnet, an electromotive force is generated in a coil wound around the coil bobbin.

[0003]

However, in the case of such a conventional microphone device, the coil bobbin in which the coil is wound around the lower surface inside the elastic diaphragm vibrates in the permanent magnet in accordance with a change in the magnetic field. Since the coil is wound around the electromotive force, that is, a structure that generates an analog voltage signal, the external sound collected by the microphone device, for example,
In the case of digital recording on a digital audio tape recorder (DAT), an external sound signal picked up by a microphone device is once converted by an analog / digital converter, and then magnetic tape. Had to be digitally recorded. As a result, the use of the analog / digital converter not only increases the size of the entire digital recording system but also increases the cost. The present invention has been made to solve such a conventional problem, and has a simple configuration to convert an input external sound without using an analog / digital converter.
It is an object of the present invention to provide a digital microphone device that can convert and output a digital external sound signal.

[0004]

In order to achieve the above object, the present invention provides a circuit board having a through hole, and a dome fixed on the circuit board so as to surround the through hole. An elastic swelling body, a vertical body integrally formed on the lower surface inside the elastic swelling body so as to be able to reciprocate in the through hole, and a multilayer magnetized body provided on the outer peripheral surface of the vertical body. A plurality of magnetoresistive elements fixed at positions on the circuit board opposite to the magnetized body. The plurality of magnetoresistive elements output, for example, an absolute position signal indicating an absolute position of the elastic swelling body.

[0005]

According to the first aspect of the present invention, on the circuit board,
When the dome-shaped elastic swelling body fixed so as to surround the through hole vibrates due to sound pressure, the elastic swelling body, a vertical body formed on the lower surface inside the bulging body, and an outer peripheral surface of the vertical body Since the provided multilayer magnetized body also vibrates in the same manner, a digital position signal corresponding to the vibration position of the vertical body (for example, the absolute position of the magnetized body) is obtained from each of the magnetoresistive elements provided at a position facing the magnetized body. (An absolute digital position signal indicating the actual vibration position). As a result, with a simple configuration, it is possible to generate a digital position signal corresponding to the vibration position of the elastic bulging body that vibrates due to sound pressure.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a partially cutaway side view showing an embodiment of a digital microphone device according to the present invention, FIG. 2 is an exploded perspective view showing a main part of the digital microphone device shown in FIG. 1, and FIG. FIG. 4 shows a digital signal of many bits output from each magnetoresistive element side.
FIG. 5 is a diagram showing the stored contents of a ROM for converting into corresponding absolute position information, and FIG. 5 is a diagram showing a circuit configuration of a tone generator using a digital microphone device according to this embodiment.

As shown in FIGS. 1 and 2, a digital microphone device 12 according to this embodiment has a circuit board 14 having a through hole 13 and is fixed on the circuit board 14 so as to surround the through hole 13. A dome-shaped elastic swelling body 15, a cylindrical vertical body 16 integrally formed on the lower surface inside the elastic swelling body 15 so as to be able to reciprocate in the through hole 13, A multilayer magnetized body 17 provided on the outer peripheral surface of the body 16, and a plurality of magnetoresistive elements 1 fixed at positions around the through hole 13 opposed to the magnetized body 17.
And 8. In the lower part of the elastic swelling body 15, sheet portions 20 fixed on the circuit board 14 with an adhesive are integrally formed. Also, on the circuit board 14, a conductive pattern 2 for guiding an output signal output from each magnetoresistive element 18 to an electronic circuit section (see FIG. 2).
1 is formed.

In the magnetized body 17, the vertical body 16 may be formed of a magnetic material, and a multilayer magnetized body 17 may be formed on the outer peripheral surface by magnetizing directly by a well-known magnetizing method. Here, a thin cylindrical magnetized body 17 is fixed to the outer periphery of the vertical body 16. As shown in FIG. 3, which shows a part of the magnetized body 17, the magnetized body 17 is formed by connecting the S pole and the N pole of the permanent magnet to each other as shown in FIG.
Are magnetized so as to correspond to an array pattern representing a multi-bit digital signal shown in FIG. For example, a case where the S pole and the N pole of the permanent magnet are magnetized to correspond to an array pattern representing a 16-bit digital signal of 4 bits will be described. As shown in FIG. 3, the magnet is magnetized in four rows in the horizontal direction. In the first row on the left, 16 S-poles and N-poles are alternately magnetized, and in the second row, Eight alternately magnetized S and N poles are half, and in the third column, the alternately magnetized S and N poles are half, 4
In the fourth column on the rightmost side, there are S poles and N poles alternately magnetized.
Two more poles, half of which are magnetized, are arranged. The S and N poles of the permanent magnet are arranged in 16 stages in the vertical direction. The magnetization areas of the S pole and the N pole can be performed on a micron order, if necessary.

On the other hand, a large number of magnetoresistive elements 18 are fixed at positions on the circuit board 14 opposite to the magnetized positions of the S and N poles of the large number of rows, as described above. Therefore, when the magnetized body 17 vibrates vertically inside the through hole 13 according to the vibration of the elastic swelling body 15 due to the sound pressure,
In accordance with the vibration of the magnetized body 17, the magnetized positions of the S-poles and N-poles in many rows also oscillate in the vertical direction. The resistance values of a large number of magnetoresistive elements 18 are sequentially changed in accordance with the above, and a large number of output signals are simultaneously and sequentially outputted. And outputs it to the CPU 22 as an absolute position signal.

Next, a circuit configuration of a tone generator using the digital microphone device according to this embodiment will be described with reference to FIG. That is, as shown in FIG. 5, a CPU (Central Processing Unit) 22 for performing all electronic control of the musical tone generator 13 is provided with a wave-shaped output signal output from a large number of magnetoresistive elements 18 as described above. Into a square wave signal, and each of the square wave signals simultaneously output from the waveform shaping circuit 23 (these square wave signals correspond to a digital signal of many bits).
ROM2 which sequentially converts and outputs corresponding absolute position information
4 (see FIG. 4), a RAM 25 for temporarily temporarily storing the absolute position information sequentially output from the ROM 24, and control in accordance with musical tone characteristic instruction information corresponding to the absolute position information temporarily stored in the RAM 25. Sound source 26,
A digital / analog converter 19 that converts each rectangular wave signal (a multi-bit digital signal) output simultaneously from the waveform shaping circuit 23 into a corresponding analog voltage signal is connected. The ROM 24 receives a large number of rectangular wave signals (a, b, c, d in FIG. 4).
Indicates that there are rectangular wave signals from the four magnetoresistive elements 18,
), And converts the inputted multiple rectangular wave signals (digital signals of many bits) into the corresponding absolute position information and outputs it. The sound source 26 is connected to an amplifier 27 for amplifying a tone signal output from the sound source 26, and the amplifier 27 is connected to a speaker 28 for emitting the amplified tone signal to the outside. I have.

Next, the operation according to this embodiment will be described. Here, a case will be described as an example where a wave-shaped output signal is simultaneously output from the four magnetoresistive elements 18 in accordance with an external sound pressure. First, when a sound pressure is externally applied from the state shown in FIG. 1, the upper part of the elastic swelling body 15 gradually descends, and the vertical body 16 also descends accordingly. Then, since the magnetized body 17 is provided on the outer peripheral surface of the vertical body 16, the magnetized body 17 also descends in the same direction. Then, for each of the lowered positions of the magnetized members 17, each of the magnetoresistive elements 18 fixed on the circuit board 14 opposed thereto.
Thus, signals having different waveforms are simultaneously output in different forms. That is, before the sound pressure is applied, all the magnetoresistive elements 18 are all S
When sound pressure starts to be applied from the state of facing the magnetized body 17 at the position of the arrangement pattern of the poles, as shown in the following arrangement from the bottom in FIG. Are shifted to the state where the magnetoresistive elements 18 face each other at the position of the arrangement pattern of the S poles, and in response, only the wave shape from the magnetoresistive element 18 facing the N pole in the first row responds. Is output. Further, when a sound pressure is applied, as shown in the third arrangement from the bottom in FIG. 3, each of the magnetoresistive elements 18 is arranged at the position of the arrangement pattern of N poles in the second column and S poles in the other columns.
In response to this, in response, a wave-shaped signal is output only from the magnetoresistive element 18 facing the N pole in the second column. Subsequently, when a strong sound pressure is applied, as shown in the arrangement from the bottom in FIG.
When each of the magnetoresistive elements 18 is opposed to each other at the arrangement pattern of the N-pole in the second row and the N-pole and the S-pole in the third and fourth rows, the Two magnetoresistive elements 1 facing the N poles of the first and second columns
8 simultaneously outputs a wave-shaped signal.

As described above, when the elastic swelling body 15 vibrates in the vertical direction according to the sound pressure from the outside, and the magnetized body 17 also vibrates in the same direction in accordance with the vibration, the wavy shape of the magnetoresistive element 18 is differently formed. Output signals are output simultaneously and sequentially. Then, the output signals of these wave shapes are shaped into rectangular wave signals by the respective waveform shaping circuits 23,
2 is input. Each input waveform shaping signal (corresponding to the 4-bit digital signal shown in FIG. 4) is converted into the corresponding absolute position information in the ROM 24 (step 6-1 in FIG. 6). The converted absolute position information is stored in the RAM 25
(Step 6-2 in FIG. 6). CPU 22
Stores the written absolute position information in the RAM 25 immediately.
, And transmits tone characteristic instruction information corresponding to the read absolute position information to the sound source 26 (step 6-3 in FIG. 6). For this reason, based on the tone characteristic indication information corresponding to the above-described absolute position information, the corresponding volume,
A tone signal having a tone color or the like is output from the sound source 26. This tone signal is sequentially emitted as a tone from a speaker 28 via an amplifier 27. Therefore, musical tones having a volume, tone, and the like corresponding to the magnitude of the sound pressure can be sequentially emitted from the speaker 28 to the outside.

The digital / analog converter 19 converts each waveform shaping signal (corresponding to a multi-bit digital external sound signal shown in FIG. 4) sequentially output from each waveform shaping circuit 23 to a corresponding analog external sound signal. If you convert sequentially,
The external sound input to the digital microphone device 12 is
Without using an analog / digital converter, directly
The digital / digital converter 19 converts the multi-bit digital external sound signal into a digital external sound signal.
The analog external sound signal can be sequentially emitted from the speaker 28 in a form amplified by the amplifier 27.

[0014]

As is apparent from the above description, according to the present invention, there is provided a circuit board having a through hole, and a dome-shaped elastic member fixed on the circuit board so as to surround the through hole. A swelling body, a vertical body integrally formed on the lower surface inside the elastic swelling body so as to be able to reciprocate in the through hole, a multilayer magnetized body provided on an outer peripheral surface of the vertical body, Since it has a plurality of magneto-resistive elements fixed at positions on the circuit board facing the magnetic body, it is possible to directly input an external sound without using an analog / digital converter with a simple configuration. Can be converted into a digital external sound signal and output.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of a digital microphone device according to the present invention.

FIG. 2 is an exploded perspective view showing a main part of the digital microphone device shown in FIG. 1;

FIG. 3 is a front view showing a part of a magnetized body.

FIG. 4 shows a digital signal of many bits output from each magnetoresistive element side. FIG. 4 is a diagram showing the storage contents of a ROM that converts the information into corresponding absolute position information.

FIG. 5 is a diagram showing a circuit configuration of a tone generator using the digital microphone device according to the embodiment.

FIG. 6 is a flowchart showing a process from conversion into absolute position information by a CPU to transmission of musical tone characteristic instruction information to a sound source.

[Explanation of symbols]

 Reference Signs List 12 digital microphone device 13 through hole 14 circuit board 15 elastic swelling body 16 vertical body 17 magnetized body 18 magnetoresistive element 22 CPU 26 sound source

Claims (2)

(57) [Claims] A circuit board having a through hole; a dome-shaped elastic swelling body fixed on the circuit board so as to surround the through hole; and a lower surface inside the elastic swelling body. A vertical body integrally formed so as to be able to reciprocate in the through-hole, a multilayer magnetized body provided on an outer peripheral surface of the vertical body, and a plurality of magnetized bodies fixed at positions on the circuit board facing the magnetized body. A digital microphone device comprising: a magnetoresistive element according to claim 1. 2. The digital microphone device according to claim 1, wherein the plurality of magnetoresistive elements output an absolute position pulse signal indicating an absolute position of the elastic swelling body.