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Class Information
Number: 381/121
Name: Electrical audio signal processing systems and devices > With amplifier > Feedback
Description: Subject matter where a fraction of an output signal is returned to an input.
Patents under this class:
| Patent Number |
Title Of Patent |
Date Issued |
| 7570714 |
Data transfer apparatus for low voltage differential signaling |
Aug. 4, 2009 |
| 7567908 |
Differential dynamic content delivery with text display in dependence upon simultaneous speech |
Jul. 28, 2009 |
| 7362871 |
Audio amplifier circuit and audio IC having the same |
Apr. 22, 2008 |
| 6975734 |
Audio apparatus of negative driving with adaptive gain control |
Dec. 13, 2005 |
| 6792121 |
Audio signal amplifier circuit and portable telephone set and portable electronic device using the same audio signal amplifier circuit |
Sep. 14, 2004 |
| 6593809 |
Circuit for widening the stereobase in the reproduction of stereophonic sound signals |
Jul. 15, 2003 |
| 6563380 |
Dual bridge amplifier |
May. 13, 2003 |
| 6434243 |
Power amplifier |
Aug. 13, 2002 |
| 6407633 |
Methods and apparatus for stabilizing feedback-controlled amplifiers |
Jun. 18, 2002 |
| 6300825 |
PWM amplifier with feedback loop integrator |
Oct. 9, 2001 |
| 6239655 |
Microphone amplifier with digital gain control |
May. 29, 2001 |
| 6172561 |
High volume expander circuit |
Jan. 9, 2001 |
| 6160450 |
Self-biased, phantom-powered and feedback-stabilized amplifier for electret microphone |
Dec. 12, 2000 |
| 6127888 |
Power amplification device |
Oct. 3, 2000 |
| 6049618 |
Hearing aid having input AGC and output AGC |
Apr. 11, 2000 |
| 6035049 |
AC coupling and signal amplification using switched capacitors |
Mar. 7, 2000 |
| 5953430 |
Filter circuit and audio signal processor provided therewith |
Sep. 14, 1999 |
| 5939938 |
Amplifier circuit with reduced DC power related turn-on and turn-off transients |
Aug. 17, 1999 |
| 5909145 |
Variable control of electronic power supplies |
Jun. 1, 1999 |
| 5815040 |
Wide bandwidth, current sharing, MOSFET audio power amplifier with multiple feedback loops |
Sep. 29, 1998 |
| 5796305 |
Amplifier arrangements with high damping factor |
Aug. 18, 1998 |
| 5787182 |
Audio signal amplifier circuit and a portable audio equipment using the same |
Jul. 28, 1998 |
| 5751823 |
Audio amplifier system with improved isolation between preamplifier and power amplifier |
May. 12, 1998 |
| 5719526 |
Internal load monitor for amplifier |
Feb. 17, 1998 |
| 5705950 |
Hybrid solid state/vacuum tube audio amplifier |
Jan. 6, 1998 |
| 5703529 |
Amplifier circuit with reduced DC power related transients |
Dec. 30, 1997 |
| 5610555 |
Low-voltage driven, audio signal amplifying apparatus and a portable acoustic system using said apparatus |
Mar. 11, 1997 |
| 5543759 |
Audio amplification circuits |
Aug. 6, 1996 |
| 5537081 |
No turn-on pop noise amplifier |
Jul. 16, 1996 |
| 5399986 |
Isolated multi-output power amplifier |
Mar. 21, 1995 |
| 5363062 |
Audio amplifier on-off control circuit |
Nov. 8, 1994 |
| 5357214 |
Methods and apparatus for microphone preamplification |
Oct. 18, 1994 |
| 5343159 |
Direct box employing hybrid vacuum tube and solid state circuitry |
Aug. 30, 1994 |
| 5266905 |
Audio amplifier with amplified feedback |
Nov. 30, 1993 |
| 5245296 |
Audio amplifier circuit and method of operation |
Sep. 14, 1993 |
| 5227735 |
Technique to drive transformer coupled line amplifier |
Jul. 13, 1993 |
| 5197099 |
Multiple-channel audio reproduction apparatus |
Mar. 23, 1993 |
| 5191616 |
Acoustic apparatus |
Mar. 2, 1993 |
| 5191298 |
Isolation amplifier circuit |
Mar. 2, 1993 |
| 5134658 |
Apparatus for discriminating information signals from noise signals in a communication signal |
Jul. 28, 1992 |
| 5130666 |
Balanced microphone preamplifier in CMOS technology |
Jul. 14, 1992 |
| 5119430 |
Sound amplifier system |
Jun. 2, 1992 |
| 5103190 |
Driving apparatus, and control information storage body and protection circuit therefor |
Apr. 7, 1992 |
| 5032796 |
Solid state amplifier simulating vacuum tube distortion characteristics |
Jul. 16, 1991 |
| 4979218 |
Balanced output circuit |
Dec. 18, 1990 |
| 4845757 |
Circuit for recognizing oscillations in a useful signal due to feedback between acoustic input and output transducers |
Jul. 4, 1989 |
| 4801889 |
Amplifier for amplifying input signal voltage and supplying the same |
Jan. 31, 1989 |
| 4747144 |
Amplifier with automatic inhibition of acoustic feedback |
May. 24, 1988 |
| 4675835 |
Device for compensating reproduction errors in an electroacoustic transducer |
Jun. 23, 1987 |
| 4649565 |
Electro-acoustic converter with compensated frequency response characteristic |
Mar. 10, 1987 |
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