Superheterodyne radio receiver with nearby-station interference detection
First Claim
Patent Images
1. In a superheterodyne radio receiver including an RF amplifier stage and an IF amplifier stage,the improvement comprising:
- interference-detecting means associated with said RF amplifier stage and said IF amplifier stage for detecting the occurrence of an interference caused by reception of an interfering channel signal of an adjacent station at a frequency close to that of a desired station signal to be received by said radio receiver,wherein said interference-detecting means comprises;
first circuit means for detecting the fact that an RF signal level at said RF amplifier stage is higher than a first reference level and for delivering a first signal upon such detection;
second circuit means for detecting the fact that the IF signal level at said IF amplifier stage is lower than a second reference level and for delivering a second signal upon such detection; and
third circuit means responsive to said first and second circuit means for generating a detection signal when receiving both of said first and second signals supplied from said first and second circuit means,said detection signal being an indication of the occurrence of said interference by the adjacent channel signal in said receiver.
0 Assignments
0 Petitions
Accused Products
Abstract
In a superheterodyne radio receiver, by observing the RF and IF signal levels is detected an occurrence of an interference caused by an interfering strong signal of an adjacent station at a frequency close to that of a desired station signal to be received by the receiver. In case such interference is detected, a cancelling signal is fed to the RF amplifier stage to cancel out this interfering station signal, or the selectivity of the RF amplifier stage is set to be sharper in order to reject the interfering station signal.
22 Citations
11 Claims
-
1. In a superheterodyne radio receiver including an RF amplifier stage and an IF amplifier stage,
the improvement comprising: -
interference-detecting means associated with said RF amplifier stage and said IF amplifier stage for detecting the occurrence of an interference caused by reception of an interfering channel signal of an adjacent station at a frequency close to that of a desired station signal to be received by said radio receiver, wherein said interference-detecting means comprises; first circuit means for detecting the fact that an RF signal level at said RF amplifier stage is higher than a first reference level and for delivering a first signal upon such detection; second circuit means for detecting the fact that the IF signal level at said IF amplifier stage is lower than a second reference level and for delivering a second signal upon such detection; and third circuit means responsive to said first and second circuit means for generating a detection signal when receiving both of said first and second signals supplied from said first and second circuit means, said detection signal being an indication of the occurrence of said interference by the adjacent channel signal in said receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
Specification