Abstract: Over the air signaling of dynamic frequency selection operating parameters to client devices is disclosed. In an embodiment, a multi-channel master device determines a maximum range value of a radar detection umbrella associated with the multi-channel master device based on a first range representing a range at which the multi-channel master device detects a first radar transmission transmitted by a radar device at a defined transmission power; determines a compliance range value based on a second range representing a range at which the multi-channel master device detects a second radar transmission transmitted by the radar device at a dynamic frequency selection (DFS) compliance threshold transmission power; and determines a margin range value based on a third range representing a range at which the multi-channel master device detects a third radar transmission transmitted by the radar device at a transmission power that is lower than the dynamic frequency selection compliance threshold transmission power.

Abstract: Over the air signaling of dynamic frequency selection operating parameters to client devices is disclosed. In an embodiment, a multi-channel master device determines a maximum range value of a radar detection umbrella associated with the multi-channel master device based on a first range representing a range at which the multi-channel master device detects a first radar transmission transmitted by a radar device at a defined transmission power; determines a compliance range value based on a second range representing a range at which the multi-channel master device detects a second radar transmission transmitted by the radar device at a dynamic frequency selection (DFS) compliance threshold transmission power; and determines a margin range value based on a third range representing a range at which the multi-channel master device detects a third radar transmission transmitted by the radar device at a transmission power that is lower than the dynamic frequency selection compliance threshold transmission power.

Abstract: Over the air signaling of dynamic frequency selection operating parameters to client devices is disclosed. In an embodiment, a multi-channel master device determines a maximum range value of a radar detection umbrella associated with the multi-channel master device based on a first range representing a range at which the multi-channel master device detects a first radar transmission transmitted by a radar device at a defined transmission power; determines a compliance range value based on a second range representing a range at which the multi-channel master device detects a second radar transmission transmitted by the radar device at a dynamic frequency selection (DFS) compliance threshold transmission power; and determines a margin range value based on a third range representing a range at which the multi-channel master device detects a third radar transmission transmitted by the radar device at a transmission power that is lower than the dynamic frequency selection compliance threshold transmission power.

Abstract: Apparatus and methods mitigate a problem of equalizing communications signals that have been distorted by severe non-linearities such as clipping or harsh compression. For example, severe non-linearity occurs when signal compression or signal clipping occurs at rates above 20% of the data transmission interval. Severe non-linearities may significantly reduce system performance. Disclosed techniques selectively apply DSP equalization based on the detection of non-linearity for a present sample or one or more samples prior to the present sample. These techniques can be implemented in relatively low-cost high-speed SerDes designs to improve eye openings and reduce sensitivity to InterSymbol Interference (ISI) and to improve bit error rate (BER).

Abstract: Apparatus and methods generate equalizer coefficients for an equalizer of a receiver. In a high-speed receiver, received symbols can be subject to inter-symbol-interference (ISI). An equalizer can compensate for ISI and improve a bit error rate (BER). However, traditional adaptive techniques to generate coefficients for equalization can generate corrupted coefficients when equalized samples used for adaptation are based on clipped or heavily compressed signals. In certain situations, the clipping rate can be relatively high, such as over 20%. Equalizer performance is improved when the equalized symbols used directly or indirectly for adaptation are selected such that equalized symbols based on clipped input samples are not used for adaptation.

Abstract: Apparatus and methods mitigate a problem of equalizing communications signals that have been distorted by severe non-linearities such as clipping or harsh compression. For example, severe non-linearity occurs when signal compression or signal clipping occurs at rates above 20% of the data transmission interval. Severe non-linearities may significantly reduce system performance. Disclosed techniques selectively apply DSP equalization based on the detection of non-linearity for a present sample or one or more samples prior to the present sample. These techniques can be implemented in relatively low-cost high-speed SerDes designs to improve eye openings and reduce sensitivity to InterSymbol Interference (ISI) and to improve bit error rate (BER).

Abstract: Apparatus and methods control predistortion of an RF transmitter. A base station or a mobile station can utilize predistortion to improve linearity characteristics of the RF power amplifier. When used effectively, predistortion limits spectral growth such that the amplified signal complies with regulatory requirements. With respect to bursty signals, specific improvement techniques are disclosed. A first technique is related to adaptation using only a smaller subset of samples of a burst. A second technique is related to selective application of digital predistortion, such as, only under high power conditions for a power amplifier. A third technique is directed to adaptation of less than all of the coefficients. These improvements permit the use of a smaller and less expensive amplifier for a given power class and can lengthen battery life for a mobile unit.

Abstract: A low-complexity digital linear equalizer whose operation and adaptation makes stabilized digital timing recovery practical. The technique is fundamental for the operation of communications receivers employing digital timing recovery, e.g., in a modem. A technique for automatically adjusting the parameters of a digital linear equalizer to compensate for low-pass impairments while maintaining a relatively constant timing characteristic is described.

Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.

Abstract: A predistortion system adaptively compensates for distortion introduced along one or more amplification chains of a power amplifier system. In one embodiment, the predistortion system includes a plurality of compensation circuits, each of which is coupled to, and configured to digitally predistort an input transmission signal to, a respective amplification chain of an antenna array system. Each such amplification chain has an output coupled to a respective antenna of the antenna array system. A processing unit monitors the input transmission signals to, and corresponding output signals from, each of the amplification chains on a time-shared basis, and generates updates to the compensation parameters used the corresponding compensation circuits.

Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM-AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.

Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM—AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.

Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM—AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.

Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM-AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets arc preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.

Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM-AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.

Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM-AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.

Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM—AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.

Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM-AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.

Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM-AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.