U-blox Ag

Leo Laughlin

Christopher Brian Marshall

John Haine

Chunqing Zhang

An apparatus includes a receiver chain includes an input node and a transmitter chain comprising a tap and output nodes. An auxiliary transmitter chain comprises an auxiliary input node coupled to the tap node, an adaptive filter unit and a signal output coupled to the input node. The filter unit includes an interpolation processor, and an adaptive filter and a coefficient processor coupled to the receiver chain and the adaptive filter. The transmitter chain generates a first waveform comprising a plurality of frequency-separated signals. Contemporaneously, the auxiliary chain applies a second waveform comprising another plurality of frequency-separated signals at the input node. The receiver chain receives a composite waveform comprising a waveform coupled from the output node and the second waveform. The first waveform lacks signals required for determination of coefficients of the filter whose frequencies coincide with the another plurality of signals of the second waveform.

Active interference cancellation apparatus, signal isolation control apparatus and method of actively cancelling interference

A duplexing apparatus comprises a reference of impedance settings and corresponding calibration measurements. A controller is arranged to set a variable impedance to a first impedance setting and transmit a first transmit signal at a first transmit frequency and measure a resulting first signal at an output node of a hybrid circuit. The controller then selects a second impedance setting, transmits a second transmit signal at a second transmit frequency and measures a resulting second signal at the output node. The controller then determines a balancing result using a system of equations associating the first and second measured signals, and first and second calibration measurements from the reference in respect of the first and second impedance settings, respectively. A third impedance setting is retrieved from the reference by reference to the balancing result to provide isolation of an input node from the output node of the hybrid circuit.

Methods and apparatus for duplexing signals

A signal isolation control apparatus for controlling duplexing of signals to be transmitted through and received from an antenna. The apparatus includes a transmitter chain tap input for coupling to a transmitter chain. An auxiliary transmitter chain is operably coupled to the transmitter chain tap input for processing a transitory signal tapped from the transmitter chain, the auxiliary transmitter chain including an adaptive filter unit and a balance node output for operably coupling to a balance node of a hybrid junction. The adaptive filter unit has a signal leakage monitoring input for operably coupling to an output node of the hybrid junction. The auxiliary transmitter chain is arranged to process the tapped transitory signal in order to generate and apply an isolation signal at the balance node output for maximizing isolation of an output node of the hybrid junction from an input node of the hybrid junction.

Signal isolation control apparatus and method of controlling a hybrid junction

The invention provides duplexing apparatus, wireless devices and methods for duplexing signals in which measurements are taken at multiple frequencies across a frequency band of interest, and in which a balancing impedance is controlled as a function of those measurements. Isolation between the RX and TX nodes is enhanced across the frequency band as a result.

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Bristol, United Kingdom

Leo Laughlin