By-passing adjacent channel interference removal in receivers

• US 20040018824A1
• Filed: 07/26/2002
• Published: 01/29/2004
• Est. Priority Date: 07/26/2002
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Fang, George
• Granted Patent: US 6,999,742 B2
• Time in Patent Office: Days
• US Class Current: 455/302
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input

Abstract

A heterodyne receiver includes a tuner to select a frequency of a received signal and a converter to change the frequency of the received signal to an intermediate frequency. A single-pole/double throw switch has an input coupled to an output of the converter, a first output connected to a first band-pass filter and a second output connected to an amplifier. A second band-pass filter is coupled to an output of the amplifier, and a demodulator is coupled to an output of the second band-pass filter to produce an output signal and a characteristics signal. A logic circuit is coupled to receive the characteristics signal and for by-passing the first band-pass filter if the characteristics signal is less than a predetermined threshold.

Claims

1. A heterodyne receiver comprising:

a tuner configured to select a frequency of a received signal;

a converter, coupled to an output of the tuner, for changing the frequency of the received signal to an intermediate frequency;

a single-pole/double throw switch having an input coupled to an output of the converter;

a first band-pass filter coupled to a first output of the single-pole/double throw switch;

an amplifier coupled to a second output of the single-pole/double throw switch and the first band-pass filter;

a second band-pass filter coupled to an output of the amplifier;

a demodulator coupled to an output of the second band-pass filter to produce an output signal and a characteristics signal; and

a logic circuit coupled to receive the characteristics signal and by-passing the first band-pass filter if the characteristics signal is less than a predetermined threshold.

2. The receiver of claim 1 wherein the receiver includes a plurality of band-pass filters, and further comprising means for selectively by-passing any of the plurality of band-pass filters.

3. The receiver of claim 1 wherein the characteristic signal is a function of an input to the demodulator and of the output signal.

4. The receiver of claim 3 wherein the characteristics signal is a function of a signal-to-noise ratio, an estimate of adjacent channel interference strength, and an estimated error of the output signal.

5. A method for processing an input signal, comprising:

receiving the input signal at a selected frequency;

converting the input signal at the selected frequency to an intermediate frequency;

filtering the input signal at the intermediate frequency;

demodulating the filtered input signal to produce an output signal and a characteristics signal; and

by-passing the filtering if the characteristics signal is less than a predetermined threshold.