Patent ID: 8798546
Filing Date: 2014-08-05
Classification: H04B

Abstract:
1. A method to reduce interference between an interfering transmitted signal and a received signal in a transceiver, comprising the steps of: receiving a transmitter signal at a first port of a directional coupler; splitting the transmitter signal into a first transmit portion directed to a second port of the directional coupler, and a second transmit portion directed to a third port of the directional coupler, wherein the second port is coupled to an antenna and the third port is coupled to an adjustable impedance; filtering the second transmit portion by use of the adjustable impedance to produce a filtered second transmit portion; reflecting at least a portion of the filtered second transmit portion into the third port of the directional coupler; receiving an incoming signal at the second port of the directional coupler, the incoming signal including a received portion and a reflected portion, wherein the reflected portion is a partial reflection of the first transmit portion; combining the incoming signal at the second port of the directional coupler and the reflected signal at the third port of the directional coupler, to produce a combined signal at a fourth port of the directional coupler, and adjusting the adjustable impedance based on a spectral, temporal, and/or power characteristic of the transmitter signal and a spectral, temporal, and/or power characteristic of an impedance load coupled to the second port; wherein, in the combined signal, the reflected signal from the third port cancels at least a portion of the partial reflection of the first transmit portion from the second port; wherein the adjustable impedance produces a notch frequency rejection in the combined signal using Z where {b i } i=0 3 are real constants and ω is an angular frequency, the notch frequency centered at a carrier frequency of the transmitter signal, and ω 0 is a nominal angular frequency.