RF receiver AGC incorporating time domain equalizer circuity

• US 5,509,030 A
• Filed: 03/04/1992
• Issued: 04/16/1996
• Est. Priority Date: 03/04/1992
• Status: Expired due to Term

• Current Assignee: Alcatel Network Systems India Limited (Nokia Corporation)
• Original Assignee: Alcatel Network Systems India Limited (Nokia Corporation)
• Inventors: Mortensen, Duane L.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): PHAN, HAI
• Application Number:
  US07/846,496
• Time in Patent Office: 1,504 Days
• Field of Search: 375/98, 375/11-16, 455/243.1, 455/240.1, 328/168, 328/175
• US Class Current: 375/232
• CPC Class Codes: H03G 3/001 Digital control of analog signals
• CPC Class Codes: H03G 3/3068 Circuits generating control signals for both R.F. and I.F. stages
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22
• CPC Class Codes: H04L 27/08 Amplitude regulation arrangements
• CPC Class Codes: H04L 27/3809 Amplitude regulation arrangements

Abstract

Feedback signals for use in controlling a variable gain amplifier portion of a radio receiver are obtained from existing automatic gain control signals comprising a part of a time domain equalizer section of a receiver such that bandpass filtering and feedback signal detecting circuitry, along with detector circuitry linearization apparatus required in prior art feedback schemes, can be eliminated from the overall scheme. The resulting apparatus provides a constant level to the input of the incorporated analog-to-digital converter and the resultant loop adapts to changing RF/baseband bandwidths.

Claims

1. A method of providing automatic gain control (AGC) in a radio receiver comprising the steps of:

a) gain controllably amplifying a radio frequency input signal to provide a variable amplitude signal;

b) filtering said variable amplitude signal to provide analog filtered signals;

c) time domain equalizing (TDE) said analog filtered signals by analog to digital (A/D) converting, logically combining, and integrating same to provide an AGC signal, and returning a version of said AGC signal to a summer at an input of the TDE step for controlling a gain of the TDE step portion of the radio receiver; and

d) filtering and threshold detecting said AGC signal before using same to gain control said radio frequency input signal.

2. A method of providing automatic gain control (AGC) in a radio receiver comprising the steps of:

a) gain controllably amplifying a radio frequency input signal to provide a variable amplitude signal;

b) filtering said variable amplitude signal to provide an analog filtered signal;

c) time domain equalizing (TDE) said analog filtered signal by analog to digital (A/D) converting, logically combining and integrating same to provide an AGC signal and returning a version of said AGC signal to a summer at an input of the TDE step for controlling a gain of the TDE step portion of the radio receiver; and

d) filtering and threshold detecting said AGC signal before using same to gain control said radio frequency input signal.

3. A method of providing automatic gain control (AGC) in a radio receiver, comprising the steps of:

gain controllably amplifying a radio frequency input signal to generate a variable amplitude signal;

filtering said variable amplitude signal to generate analog filtered signals;

time domain equalizing said analog filtered signals by analog to digital converting, logically combining, and integrating said analog filtered signals to generate an AGC signal;

summing said AGC signal with said analog filtered signals to control gain through said time domain equalizing step;

buffering said AGC signal to produce a buffered AGC signal;

filtering said buffered AGC signal to produce a filtered AGC signal;

threshold detecting said filtered AGC signal to produce a feedback AGC signal; and

summing said feedback AGC signal with said radio frequency input signal to control gain through said gain controllably amplifying step.