DIGITAL MICROPHONE WITH ADJUSTABLE GAIN CONTROL

• US 20160087596A1
• Filed: 09/16/2015
• Published: 03/24/2016
• Est. Priority Date: 09/19/2014
• Status: Active Grant

• Current Assignee: Knowles Electronics Llc (Knowles Corporation)
• Original Assignee: Knowles Electronics Llc (Knowles Corporation)
• Inventors: Frst, Claus Erdmann, Thomsen, Henrik, Yurrtas, Aziz, Hovesten, Per Flemming, Gueorguiev, Svetoslav
• Granted Patent: US 9,831,844 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H03F 3/183 with semiconductor devices only
• CPC Class Codes: H03G 3/3005 in amplifiers suitable for low-frequencies, e.g. audio amplifiers H03G3/32, H03G3/34 take precedence
• CPC Class Codes: H04R 1/04 Structural association of microphone with electric circuitry therefor in deaf-aid sets H04R25/00

Abstract

Approaches are provided for an apparatus that includes an input buffer, an analog-to-digital converter coupled to the input buffer, a decompress module coupled to the analog to digital converter, and a gain control module coupled to the input buffer and the decompress module. The input buffer has a first adjustable gain and operating in the analog domain. The analog-to-digital converter converts the input analog data received from the input buffer into digital data. The decompress module operates in the digital domain, and is configured to decompress the digital data received from the analog-to-digital converter. The decompress module has a second adjustable gain and produces an output digital signal. The gain control module determines when to compensate for changes in characteristics the input analog data by selectively controlling the first gain of the input buffer in the analog domain and the second gain of the decompress module in the digital domain.

Claims

1. An apparatus, the apparatus comprising:

an input buffer, the input buffer configured to receive and store input analog data from a transducer, the input buffer having a first adjustable gain and operating in the analog domain;

an analog-to-digital converter coupled to the input buffer, the analog-to-digital converter configured to convert the input analog data received from the input buffer into digital data;

a decompress module coupled to the analog to digital converter, the decompress module configured to operate in the digital domain, the decompress module configured to decompress the digital data received from the analog-to-digital converter, the decompress module having a second adjustable gain and producing an output digital signal;

a gain control module coupled to the input buffer, and the decompress module, the gain control module configured to determine when to compensate for changes in characteristics the input analog data by selectively controlling the first gain of the input buffer in the analog domain and the second gain of the decompress module in the digital domain.

2. The apparatus of claim 1, wherein as the first gain is increased, the second gain is decreased, and wherein when the first gain is decreased, the second gain is increased.

3. The apparatus of claim 1, wherein the gain control module is further configured to sample a signal strength.

4. The apparatus of claim 3, wherein the gain control module is further configured to determine whether the signal strength exceeds a first pre-determined threshold.

5. The apparatus of claim 4, wherein in response to determining the signal strength exceeds the first pre-determined threshold, the gain control module is configured to decrease the first gain and increase the second.

6. The apparatus of claim 3, wherein the gain control module is further configured to determine whether the signal strength is below a second pre-determined threshold for a predetermined period of time.

7. The apparatus of claim 6, wherein in response to determining the signal strength is below a second pre-determined threshold for a predetermined period of time, the gain control module is configured to increase the first gain and decrease the second.

8. The apparatus of claim 1, further comprising an amplifier configured to amplify a signal.

9. A method, the method comprising:

receiving and storing input analog data from a transducer and an input buffer, the input buffer having a first adjustable gain;

converting the input analog data received from the input buffer into digital data;

at a decompress module configured to operate in the digital domain, the decompress module having a second adjustable gain, decompressing the digital data and producing an output digital signal;

determining when to compensate for changes in characteristics the input analog data by selectively controlling the first gain of the input buffer and the second gain of the decompress module.

10. The method of claim 9, wherein as the first gain is increased, the second gain is decreased, and wherein when the first gain is decreased, the second gain is increased.

11. The method of claim 9, further comprising sampling a signal strength.

12. The method of claim 11, further comprising determining whether the signal strength exceeds a first pre-determined threshold.

13. The method of claim 12, further comprising, in response to determining the signal strength exceeds the first pre-determined threshold, to decreasing the first gain and increasing the second.

14. The method of claim 11, further comprising determining whether the signal strength is below a second pre-determined threshold for a predetermined period of time.

15. The method of claim 14, further comprising, in response to determining the signal strength is below a second pre-determined threshold for a predetermined period of time, increasing the first gain and decreasing the second.

16. The method of claim 9, further comprising amplifying a signal.