Interference cancellation system
First Claim
1. An interference cancellation system comprising:
- (a) a main signal reception means for receiving a main signal of a desired digital signal and an undesired interference signal;
(b) an auxiliary signal reception means for receiving said undesired interference signal;
(c) a control means for providing a compensation signal having an amplitude and anti-phase equal to an amplitude and anti-phase of the undesired interference signal in the main signal;
(d) a combiner for combining the main signal and an output of said control means to cancel the undesired interference signal in the main signal;
(e) a quadrature phase detector for demodulating the main signal;
(f) a phase detector for phase detecting the undesired interference signal, said phase detector being supplied with a clock signal obtained by said quadrature phase detector for the main signal;
(g) a decision circuit coupled with an output of said quadrature phase detector, to provide a demodulated digital signal;
(h) an error signal detector for providing a difference between a decision level of said desired digital signal detector and an output of said quadrature phase detector;
(i) a correlation means for providing a correlation between an output of said error signal detector and an output of the phase detector for said undesired interference signal; and
(j) said control means being controlled by an output of said correlation means.
2 Assignments
0 Petitions
Accused Products
Abstract
An interference cancellation system at a receiver side for digital radio system has a first quadrature phase detector for demodulating the main signal. A second quadrature phase detector (or a phase detector) is supplied with the same reference carrier and clock signal as that of the first quadrature phase detector, for phase detecting an interference signal. A decision circuit is coupled with the first quadrature phase detector to provide a baseband signal. An error signal detector provides a difference between a decision level of a digital signal and an input of the decision circuit due to the interference signal. A correlation device provides a correlation signal between an error signal and a phase detected interference signal. A control device provides a compensation signal which has the same amplitude and anti-phase as those of the interference component included in the main signal according to the correlation signal. A combiner combines the main signal with the compensation signal to provide a compensated main signal which is free from interference. A combiner and a control means may be inserted either in an RF stage or an IF stage, or in a baseband stage. An error signal detector and decision circuit are implemented by an A/D converter. A correlation means is implemented by a digital or analog multiplier and integrators.
-
Citations
10 Claims
-
1. An interference cancellation system comprising:
-
(a) a main signal reception means for receiving a main signal of a desired digital signal and an undesired interference signal; (b) an auxiliary signal reception means for receiving said undesired interference signal; (c) a control means for providing a compensation signal having an amplitude and anti-phase equal to an amplitude and anti-phase of the undesired interference signal in the main signal; (d) a combiner for combining the main signal and an output of said control means to cancel the undesired interference signal in the main signal; (e) a quadrature phase detector for demodulating the main signal; (f) a phase detector for phase detecting the undesired interference signal, said phase detector being supplied with a clock signal obtained by said quadrature phase detector for the main signal; (g) a decision circuit coupled with an output of said quadrature phase detector, to provide a demodulated digital signal; (h) an error signal detector for providing a difference between a decision level of said desired digital signal detector and an output of said quadrature phase detector; (i) a correlation means for providing a correlation between an output of said error signal detector and an output of the phase detector for said undesired interference signal; and (j) said control means being controlled by an output of said correlation means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
Specification