A method of operating a communications system includes receiving a signal at a digital predistorter (DPD), introducing predistortion to the signal using the DPD, and converting the predistorted signal to an analog signal using a digital-to-analog converter having a first bandwidth. The method also includes amplifying the analog signal, sampling the amplified signal using an analog-to-digital converter having a second bandwidth less than the first bandwidth, and extracting coefficients of the DPD from the sampled signal.

Certain aspects of the present disclosure are directed to a digital predistortion (DPD) device for use within a wireless transmitter that permits the use of a downstream digital-to-analog converter that operates at a clock rate close to the bandwidth of a digital baseband input signal. In some examples, a sampling rate of a digital baseband input signal is increased using an upsampler to obtain an increased rate digital input signal. Predistortion is applied to the increased rate digital input signal using a DPD device to obtain a predistorted digital signal. The sampling rate of the predistorted digital signal is then decreased using a downsampler to obtain a lower-rate predistorted digital signal with a sampling rate below the increased rate of the upsampler (e.g. close to the bandwidth of a digital baseband input signal). A low pass filter may be provided to filter out-of-band signal components from the predistorted digital signal.

A digital predistortion linearization method is provided for increasing the instantaneous or operational bandwidth for RF power amplifiers employed in wideband communication systems. Embodiments of the present invention provide a method of increasing DPD linearization bandwidth using a feedback filter integrated into existing digital platforms for multi-channel wideband wireless transmitters. An embodiment of the present invention utilizes a DPD feedback signal in conjunction with a low power band-pass filter in the DPD feedback path.

There is provided a communication receiver comprising: an input for receiving a radio frequency, RF, input signal; and at least one finite impulse response, FIR, discrete time filter, DTF. The at least one FIR DTF comprises: an input circuit comprising an input port for sampling the RF input signal at a sampling frequency that is comparable to the input RF input signal; and N parallel branches, each branch having a set of input unit sampling capacitances, where each unit sampling capacitance is independently selectively coupleable to an output summing node. The input circuit is configured to convert an equivalent input impedance of the at least one FIR DTF around the sampling frequency to a real impedance.

A delta-sigma modulator (DSM) includes: a first summation circuit coupled to an input signal for subtracting an error feedback signal from the input signal; a tunable signal transfer function coupled to the first summation circuit for setting a desired pole in a frequency response of the DSM; a second summation circuit coupled to the tunable signal transfer function for adding a noise transfer function to an output of the tunable signal transfer function; and a quantizer coupled to the second summation circuit for quantizing an output of the second summation circuit to generate an output of the DSM. The output of the DSM is used as feedback to the first summation circuit as the error feedback signal, and the tunable signal transfer function is dynamically tuned to allow selecting and tuning a center frequency and a bandwidth of the DSM.

This invention relates to a system and method for processing signals in a signal processing system so as at least to ameliorate spurious signals generated in said signal processing system during processing of signals. The method, which is implemented by the system in accordance with the invention, typically comprises receiving a signal of unknown and arbitrary frequency within the operating frequency range of the signal processing system, wherein the input signal comprises at least a fundamental signal. The method then comprises generating, in one signal processing path, a compensation signal with same amplitude and phase as the spurious signal. The compensation signal is then subtracted from the received input signal or added out of phase to the received input signal, in another signal processing path. In this way, the spurious signal is cancelled from the received signal and/or the received signal is pre-distorted to account for spurious signals generated during further processing in the signal processing system.

The systems and methods discussed herein related to digital to analog conversion. A digital to analog conversion a compensation circuit and a digital to analog conversion circuit. The compensation circuit includes a filter configured to provide roll off compensation in a baseband frequency using real coefficients. The compensation circuit is configured to convert the first digital signal to a second digital signal so that the second digital signal can be filtered by the filter using the real coefficients.

A wireless communication method, a wearable device, a mobile terminal, and a system are provided. In the technical solution of the present disclosure, a mobile terminal sends frequency band information to a wearable device; the mobile terminal receives a second signal sent by the wearable device, converts the second signal into a second baseband signal, receives a third signal that is sent by a base station and corresponds to the frequency band information, and coverts the third signal into a third baseband signal; and the mobile terminal acquires a radio signal corresponding to the frequency band information according to the second baseband signal and the third baseband signal. In this way, data can be received through multiple paths by using communication capabilities of multiple wearable devices, and the receiving capability of a mobile phone can be greatly improved.

An adapter, for coupling a first medical instrument to a control console having a console receptacle configured for attachment thereto of a different second medical instrument, includes a case, a receptacle, circuitry contained in the case and an output connector. The receptacle is configured to receive an input connector of the first medical instrument conveying modulated analog input signals from the first medical instrument. The circuitry includes an analog/digital converter coupled to sample and digitize the analog input signals to generate digital samples, digital processing circuitry configured to digitally downconvert the digital samples so as to generate a baseband digital signal, and a digital/analog converter configured to convert the baseband digital signal to an analog baseband signal compatible with an output of the second medical instrument. The output connector is configured to be inserted into the console receptacle and to convey the analog baseband signal to the console.

Mechanisms for interferer detection can detect interferers by detecting elevated signal amplitudes in one or more of a plurality of bins (or bands) in a frequency range between a maximum frequency (f.sub.MAX) and a minimum frequency (f.sub.MIN). To perform rapid interferer detection, the mechanisms downconvert an input signal x(t) with a local oscillator (LO) to a complex baseband signal xI(t)+jxQ(t). xI(t) and xQ(t) are then multiplied by m unique pseudorandom noise (PN) sequences (e.g., Gold sequences) gm(t) to produce m branch signals for I and m branch signals for Q. The branch signals are then low pass filtered, converted from analog to digital form, and pairwise combined by a pairwise complex combiner. Finally, a support recovery function is used to identify interferers.