WO2001008442A2 - Method and agc device for controlling the amplification of a microphone with an integrated amplifier with a working point which can be adjusted by external wiring - Google Patents

Method and agc device for controlling the amplification of a microphone with an integrated amplifier with a working point which can be adjusted by external wiring

Info

Publication number
WO2001008442A2
WO2001008442A2 PCT/DE2000/001963 DE0001963W WO0108442A2 WO 2001008442 A2 WO2001008442 A2 WO 2001008442A2 DE 0001963 W DE0001963 W DE 0001963W WO 0108442 A2 WO0108442 A2 WO 0108442A2
Authority
WO
Grant status
Application
Patent type
Prior art keywords
microphone
control
voltage
supply
frequency
Prior art date
Application number
PCT/DE2000/001963
Other languages
German (de)
French (fr)
Other versions
WO2001008442A3 (en )
Inventor
Roland Aubauer
Ralf Kern
Stefano Ambrosius Klinke
Original Assignee
Siemens Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Classifications

    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03GCONTROL OF AMPLIFICATION
    • H03G3/00Gain control in amplifiers or frequency changers without distortion of the input signal
    • H03G3/004Control by varying the supply voltage
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00Circuits for transducers, loudspeakers or microphones
    • H04R3/04Circuits for transducers, loudspeakers or microphones for correcting frequency response
    • H04R3/10Circuits for transducers, loudspeakers or microphones for correcting frequency response of variable resistance microphones

Abstract

In order to control the amplification of a microphone with an integrated amplifier whereby the working point thereof can be adjusted by means of external wiring, so that no externally controllable amplifier or attenuator are required, the sensitivity of said microphone and or frequency response characteristic thereof is modified by means of a microphone supply voltage or a physical control variable which adjusts a microphone feed impedance.

Description

description

Method and AGC Emπchtung for controlling the gain of a microphone with an integrated, the operating point can be set by external circuitry of amplifier

The invention relates to a simple control of the sensitivity of microphones with integrated amplifier whose operation point can be set by an external circuit such as a field effect transistor preamplifier (FET preamplifier).

In virtually all the time m telecommunications and con- microphones and microphone capsules used sumeranwendungen is it's electret transducer with integrated FET preamplifier. This preamplifier is used to reduce the very high microphone source impedance and the gain of the microphone signal. As a rule, these are the most common source of a field effect transistor. By varying the feed impedance and the supply voltage, the operating point of the transistor and thus also the sensitivity of the microphone let others. Amendments to the microphone frequency response are possible if not only real but also complex supply impedances are admitted.

The object underlying the invention is to control the gain of a microphone with an integrated, the operating point can be set by external circuitry of amplifiers such that need no external controllable amplifier or Abschwacher s nd.

This object is achieved by the features of claims 1 and 3. FIG.

The underlying idea of ​​the invention is to supply voltage or the gain by causing the touring Mikrofonempfmdlichkeit and / or of the microphone frequency response over a Mikrofonversor- to control a physical control Large which adjusts a microphone feed impedance.

Advantageous further developments of the invention are shown m the dependent teranspruchen.

An embodiment of the invention will be explained with reference to FIGS. 1 to 3

Figures 1 to 3 each show a circuit for a simple Empfmdlichkeits- and / or frequency response of control of electret microphones, which does not require external, controllable amplifier or Abschwacher. The simplest implementation con- sists m of Empfmdlichkeits- and frequency response control over the microphone supply voltage U L.

Alternatively, it is also possible to realize the Empfmdlichkeits- and frequency response control such that the micro fonspeiseimpedanz Z L is set with a control voltage U.

An electronic control of the Speieseimpedanz Z L can be done by a controlled field effect transistor. The control range of the receiver microphone is dlichkeit via the feed impedance at up to 10 dB m dependence of the microphone supply voltage.

The advantage of this type of receiver dlichkeits- and frequency response control is to minimize the circuit scale and the costs involved. The control range is high enough for most applications.

The Empfmdlichkeitssteuerung of microphones with integrated FET preamplifier may also be advantageously used for automatic modulation of microphone signals. These circuits are designated (AGC) device generally known as "Automatic yarn Con- trol" circuits. Applications of these circuits can be found in virtually all consumer devices that have a microphone recording channel (Kassettenre- Korder, dictation systems, (handsfree) phones, etc.).

Claims

claims
1. A method for controlling the gain of a microphone with an integrated, the operating point adjustable by external wiring, that amplifier having the following features:
(a) from a microphone output voltage (U a) forming a first physical control Great (STG1)
(b) with the first physical control Great (STG1) is controlled a microphone supply voltage (U L) for altering the sensitivity and / or of the frequency response of the microphone (MF) (bl), or
(b2) (sτ U) controlled a second physical control Large, a microphone supply impedance (Z L) for altering the sensitivity and / or of the frequency response of the microphone (MF) is set.
2. The method according to claim 1, characterized in that a control voltage (U sτ) as a second physical Steuergro- SSE (U τ S) is used.
3. AGC E πchtung for controlling the gain of a microphone with an integrated, the operating point can be set by external circuitry amplifier having the following features: (a) control means (STM) for the gain of the microphone (MF) generate from a microphone output voltage (U a) a first physical control Great (STG1), (b) the control means (STM) are (BL) to a voltage source (SQ), the microphone (MF) via a microphone supply impedance (Z L) with a microphone supply voltage (U supplies, connected in such a way that with the first physical control Great (STG1) the microphone supply voltage (U L) for altering the sensitivity and / or of the frequency response of the microphone (MF) is controlled, or (b2) with a microphone supply impedance (Z) of the microphone (MF) such that with the first physical control Great (STG1) (sτ U) a second physical control Large overall is controlled via the microphone supply impedance (Z L) for Ände in sensitivity and / or of the frequency response of the microphone (MF) is set.
-4. AGC device according to claim 3, characterized in that the microphone supply impedance (Z) - according to the feature "(b2)" of claim 3 - an impedance circuit, in which a field effect transistor (FET), to whose gate terminal with respect to a reference potential as physical second control variable (O S T) a control voltage (U S τ) is applied, at the source terminal to the microphone (MF), the drain terminal connected to a first resistor (Rl) is connected in parallel to the series circuit comprising field effect transistor (FET) and the first resistance (Rl) has a series circuit of a second resistor is connected (R2), a coil (SP) and a capacitor (KO).
PCT/DE2000/001963 1999-07-23 2000-06-15 Method and agc device for controlling the amplification of a microphone with an integrated amplifier with a working point which can be adjusted by external wiring WO2001008442A3 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE1999134747 DE19934747A1 (en) 1999-07-23 1999-07-23 Microphone amplification control method e.g. for telecommunications and consumer applications
DE19934747.6 1999-07-23

Publications (2)

Publication Number Publication Date
WO2001008442A2 true true WO2001008442A2 (en) 2001-02-01
WO2001008442A3 true WO2001008442A3 (en) 2001-08-16

Family

ID=7915908

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE2000/001963 WO2001008442A3 (en) 1999-07-23 2000-06-15 Method and agc device for controlling the amplification of a microphone with an integrated amplifier with a working point which can be adjusted by external wiring

Country Status (2)

Country Link
DE (1) DE19934747A1 (en)
WO (1) WO2001008442A3 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2590434A1 (en) * 2011-11-04 2013-05-08 AKG Acoustics GmbH Filter circuit

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2239843A1 (en) * 2009-04-08 2010-10-13 Nxp B.V. Sensitivity adapting transducer

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4617555A (en) * 1985-04-17 1986-10-14 Data Distribution Devices, Inc. Receiver for audible alarm
US5862238A (en) * 1995-09-11 1999-01-19 Starkey Laboratories, Inc. Hearing aid having input and output gain compression circuits

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4617555A (en) * 1985-04-17 1986-10-14 Data Distribution Devices, Inc. Receiver for audible alarm
US5862238A (en) * 1995-09-11 1999-01-19 Starkey Laboratories, Inc. Hearing aid having input and output gain compression circuits

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2590434A1 (en) * 2011-11-04 2013-05-08 AKG Acoustics GmbH Filter circuit
US9204217B2 (en) 2011-11-04 2015-12-01 Akg Acoustics Gmbh Microphone filter system

Also Published As

Publication number Publication date Type
DE19934747A1 (en) 2001-01-25 application
WO2001008442A3 (en) 2001-08-16 application

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