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Condenser microphone and its impedance converter

A technology of condenser microphone and impedance converter, applied in the field of condenser microphone, can solve problems such as signal loss of capacitive voltage divider

Active Publication Date: 2017-10-03
GUANGDONG TAKSTAR ELECTRONIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0015] (2) The leakage current of the JFET gate will flow through the large resistance bias resistor R2
[0016] (3) The leakage current caused by the pollution of the printed circuit board will also flow through the resistor R2, so the upper limit of the resistance value of the resistor will be further limited

Method used

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  • Condenser microphone and its impedance converter
  • Condenser microphone and its impedance converter

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Embodiment Construction

[0032] The preferred embodiments of the capacitive microphone and its impedance converter of the present invention will be further described below with reference to the accompanying drawings.

[0033] The capacitive microphone provided by the embodiment of the present invention, such as figure 1 As shown, it mainly includes a capacitive transducer 10 , a bias resistor 11 , an active element (JFET 12 in this embodiment), a low-pass filter 13 and an operational amplifier 14 . The active components are selected from JFET, MOSFET, transistor, electron tube, operational amplifier or a parallel circuit for impedance transformation formed by a combination thereof.

[0034] In this embodiment, the active element is an N-channel JFET, the gate of the JFET12 is directly connected to the capacitive transducer 10, and the drain of the JFET12 is connected to a DC voltage through the port 18 (usually applied twice the bias voltage on the JFET12), the source of the JFET12 is used as the ou...

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Abstract

The embodiment of the present invention discloses a condenser microphone, which includes an impedance converter directly coupled with a transducer of the condenser microphone. The impedance converter includes an active element for impedance transformation, which is used to filter the audio output signal output by the active element and amplify the DC voltage component in the filtered signal to obtain a bias DC voltage As a set value control circuit, the bias DC voltage is applied to one end of the bias resistor. Implementing the embodiment of the present invention can omit the coupling capacitance between the capacitive transducer and the active element, thereby eliminating the bias resistor as a noise source, and then can increase the resistance value of the saved bias resistor.

Description

technical field [0001] The present invention relates to condenser microphones using DC-coupled impedance conversion. Background technique [0002] For externally polarized condenser microphones, the change in transducer capacitance is related to the acoustic sound pressure on the transducer diaphragm (such as a singer's singing voice). In order to convert the change in capacitance into an electrical signal, the transducer is charged with a constant DC voltage to make it electrostatically charged. [0003] For a transducer with stable and constant static electricity, the relationship between its capacitance and capacitor voltage is: [0004] Uc=Qc / C [0005] Among them, Uc represents the DC voltage applied to the capacitor, Qc represents the electrostatic charge on the capacitor, and C represents the capacitance of the capacitor. [0006] The above relationship is only valid under the condition that the electrostatic charge Qc on the transducer remains constant. Therefore...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04R19/04
CPCH04R3/00H04R19/04H04R2410/03
Inventor 不公告发明人
Owner GUANGDONG TAKSTAR ELECTRONIC CO LTD