Abstract: A method of reducing the noise from a transmitter at an associated receiver is disclosed. Noise contributions in active channels are identified and used to update a shared noise cancellation filter. Excluding signals from inactive channels speeds up the filter convergence to a near optimal solution. Sharing a filter across multiple channels reduces component count and power consumption.

Abstract: Aspects of this disclosure relate to a receiver for digital predistortion (DPD). The receiver includes an analog-to-digital converter (ADC) having a sampling rate that is lower than a signal bandwidth of an output of a circuit having an input that is predistorted by DPD. DPD can be updated based on feedback from the receiver. According to certain embodiments, the receiver can be a narrowband receiver configured to observe sub-bands of the signal bandwidth. In some other embodiments, the receiver can include a sub-Nyquist ADC.

Abstract: A control apparatus is provided that can provide high dynamic resolution and is suitable for inclusion within an integrated circuit. The control apparatus receives a demand signal representing a desired value of a measurand, and a feedback signal representing a present value or a recently acquired value of the measurand. The processing circuit forms a further signal a further signal which is a function of the demand and feedback signals. The further signal is then subjected to at least an integrating function. The demand signal, feedback signal or the further signal is processed or acquired in a sampled manner. The use of such sampled, i.e. discontinuous, processing allows integration time constants to be synthesized which would otherwise require the use of unfeasibly large components within an integrated circuit, or the use of off-chop components. Both of these other options are expensive.

Abstract: A system is described for forming an estimate of an unwanted signal component that may be formed as a result of non-linearities in a system. The estimate is used to form a cancellation signal which is added to an input signal to reduce the influence of the unwanted component.

Abstract: A method of reducing the noise from a transmitter at an associated receiver is disclosed. Noise contributions in active channels are identified and used to update a shared noise cancellation filter. Excluding signals from inactive channels speeds up the filter convergence to a near optimal solution. Sharing a filter across multiple channels reduces component count and power consumption.

Abstract: Aspects of this disclosure relate to a receiver for digital predistortion (DPD). The receiver includes an analog-to-digital converter (ADC) having a sampling rate that is lower than a signal bandwidth of an output of a circuit having an input that is predistorted by DPD. DPD can be updated based on feedback from the receiver. According to certain embodiments, the receiver can be a narrowband receiver configured to observe sub-bands of the signal bandwidth. In some other embodiments, the receiver can include a sub-Nyquist ADC.

Abstract: A single complex calculation for locating a dominant frequency, such as an interfering signal in a frequency range, is replaced by several much easier ones. A signal is analyzed over a first frequency range to locate at least one comparatively significant frequency component therein. This can involve analyzing, using electronic hardware, a test range of frequencies to identify a potentially significant component within the test range; and determining, using electronic hardware, if a condition for finishing the analysis has been met. If the condition has not been met, the test range is modified as a result of the analysis and the operations of analyzing and determining are repeated.

Abstract: A system is described for forming an estimate of an unwanted signal component that may be formed as a result of non-linearities in a system. The estimate is used to form a cancellation signal which is added to an input signal to reduce the influence of the unwanted component.

Abstract: A control apparatus is provided that can provide high dynamic resolution and is suitable for inclusion within an integrated circuit. The control apparatus receives a demand signal representing a desired value of a measurand, and a feedback signal representing a present value or a recently acquired value of the measurand. The processing circuit forms a further signal a further signal which is a function of the demand and feedback signals. The further signal is then subjected to at least an integrating function. The demand signal, feedback signal or the further signal is processed or acquired in a sampled manner. The use of such sampled, i.e. discontinuous, processing allows integration time constants to be synthesized which would otherwise require the use of unfeasibly large components within an integrated circuit, or the use of off-chop components. Both of these other options are expensive.

Abstract: An apparatus and method for controlling an output (50) of a digital system (10) comprising, for example, an output of a power amplifier (24) to minimise or neutralise nonlinearities such as limit cycles. The digital system comprises a nonlinearity means or limit cycle suppressor (16) to counter the limit cycle effect by intentionally introducing a second nonlinearity into the system (10) to suppress the limit cycle effect in the digital system (10).

Abstract: An apparatus and method for controlling an output (50) of a digital system (10) comprising, for example, an output of a power amplifier (24) to minimise or neutralise nonlinearities such as limit cycles. The digital system comprises a nonlinearity means or limit cycle suppressor (16) to counter the limit cycle effect by intentionally introducing a second nonlinearity into the system (10) to suppress the limit cycle effect in the digital system (10).