Abstract: A transmitter and method is provided for digitally upconverting a baseband digital signal to a modulated intermediate frequency (IF) digital signal and sigma-delta modulating the IF digital signal. The baseband digital signal is split into N phases, as can be accomplished using a polyphase interpolation technique (polyphase filter), and modulated. The modulated N phases are not recombined and each phase is further modulated, as can be accomplished using a digital-to-digital sigma-delta modulator that generates digital output signals at the same rate. A high speed digital multiplexer multiplexes the digital output signals into a single bit stream at a higher rate for subsequent power amplification and RF transmission.

Abstract: A number of parallel modulation functions are configured to provide sigma-delta modulation on a plurality of low sampling rate signals, which are representative of a high sampling rate input signal. Resultant sigma-delta modulated signals from each of the modulation functions are combined in a multiplexing fashion to create a high sampling rate output signal. The modulation functions may be interdependent, wherein error signals from the modulation functions are provided to a parallel block digital filter, which will provide a processed error signal to feed back into the input of each modulation function. The processed error signal for a given modulation function may be a function of the error signals derived from multiple ones of the modulation functions. In one embodiment, there are N modulation functions, and the operating rate of the modulation functions is fs/N wherein the sampling rate of the high frequency output signal is fs.

Abstract: A receiver and method is provided for sigma-delta converting an RF signal to a digital signal and downconverting to a digital baseband signal. The RF signal is split into N phases, as can be accomplished using a sample and hold circuit, and each phase is digitized, as can be accomplished using an analog-to-digital (A/D) sigma-delta converter. Polyphase decimation techniques and demodulation are applied to the phased signals to generate a demodulated digital signal. The demodulated digital signal is further downconverted to the appropriate baseband signal.

Abstract: A device, system, and method are provided for a power amplifier arrangement. In embodiments of a Vdd modulated power amplifier arrangement, a memory correction block includes a Vdd predictor for predicting waveform distortions of a Vdd modulated power supply and a main-path corrector for pre-distorting the input to the power amplifier arrangement as a function of the input to the power amplifier arrangement, an input envelope signal determined as a function of the input to the power amplifier arrangement, and an output of the Vdd predictor. Embodiments of the invention provide for operating power amplifier arrangements having memory. In some embodiments, methods of training the Vdd predictor and the main-path corrector of the memory correction block are provided.

Abstract: Methods and apparatus are provided for efficiently amplifying or converting a signal. An input signal is decomposed into a plurality of two state signals, each two state signal having a respective on level and off level. This may involve sigma-delta modulation and phase splitting. For amplifier applications, each of the two state signals is amplified with a respective switching power amplifier to produce a respective amplified signal. The amplified signals are combined to produce an amplified version of the input signal. Signals may be adjusted for impairments associated with a subsequent processing operation such as the combining.

Abstract: Large signal peaks (for example, peaks 105 and 110) can dramatically increase the cost of a communications device by requiring high grade power amplifiers. Peak reduction can reduce the large peaks at a cost of increasing spurious emissions. A circuit (for example, circuit 500) combining a scaling window peak reducing unit (for example, unit 507) and a filter (for example, filter 509) can effectively reduce the signal peaks without significantly increasing spurious emissions.

Abstract: A transmitter and method is provided for digitally upconverting a baseband digital signal to a modulated intermediate frequency (IF) digital signal and sigma-delta modulating the IF digital signal. The baseband digital signal is split into N phases, as can be accomplished using a polyphase interpolation technique (polyphase filter), and modulated. The modulated N phases are not recombined and each phase is further modulated, as can be accomplished using a digital-to-digital sigma-delta modulator that generates digital output signals at the same rate. A high speed digital multiplexer multiplexes the digital output signals into a single bit stream at a higher rate for subsequent power amplification and RF transmission.

Abstract: Large signal peaks (for example, peaks 105 and 110) can dramatically increase the cost of a communications device by requiring high grade power amplifiers. Peak reduction can reduce the large peaks at a cost of increasing spurious emissions. A circuit (for example, circuit 500) combining a scaling window peak reducing unit (for example, unit 507) and a filter (for example, filter 509) can effectively reduce the signal peaks without significantly increasing spurious emissions.

Abstract: A transmitter and method is provided for digitally upconverting a baseband digital signal to a modulated intermediate frequency (IF) digital signal and sigma-delta modulating the IF digital signal. The baseband digital signal is split into N phases, as can be accomplished using a polyphase interpolation technique (polyphase filter), and modulated. The modulated N phases are not recombined and each phase is further modulated, as can be accomplished using a digital-to-digital sigma-delta modulator that generates digital output signals at the same rate. A high speed digital multiplexer multiplexes the digital output signals into a single bit stream at a higher rate for subsequent power amplification and RF transmission.

Abstract: A receiver and method is provided for sigma-delta converting an RF signal to a digital signal and downconverting to a digital baseband signal. The RF signal is split into N phases, as can be accomplished using a sample and hold circuit, and each phase is digitized, as can be accomplished using an analog-to-digital (A/D) sigma-delta converter. Polyphase decimation techniques and demodulation are applied to the phased signals to generate a demodulated digital signal. The demodulated digital signal is further downconverted to the appropriate baseband signal.

Abstract: A method and apparatus for digitally representing a waveform segment defined by discrete ordered pairs of abscissae and ordinates, the ordered pairs being divided into an odd set and an even set. The method includes the steps of: for each even abscissa, generating a difference code representing a difference between an even ordinate paired with the even abscissa and the even abscissa, whereby the even ordinate paired with the even abscissa is represented as the sum of the even abscissa and the corresponding difference code; and for each odd abscissa, generating a differential code representing a differential between an odd ordinate paired with the odd abscissa and an even ordinate corresponding to the odd abscissa, whereby the odd ordinate paired with the odd abscissa is represented as the sum of the corresponding even ordinate and the corresponding differential code.

Abstract: A basestation transceiver simultaneously addressing multiple air interface standards with cost-effective and efficient allocation of the resources available at the transceiver. The invention significantly reduces the redundancy of the radio frequency equipment used in the transceiver by the use of a common digitizing rate selected to simultaneously accomodate all of the air interface protocols serviced.

Abstract: A selection diversity system and method for use in a TDMA (time division multiple access) radio system, particularly suited for DECT (Digital Enhanced Cordless Telephone) or PWT (personal wireless telephony) applications. A digitized version of a received signal is buffered long enough to allow selection diversity measurements to occur without corrupting the demodulation of the desired signal. While the received signal is being buffered, a single receiver makes a performance measurement on each of two antennas in sequence during the beginning of a received data burst, the beginning of the burst being determined by a timing signal fed back from a previous burst. The previously unused antenna is measured first to minimize the likelihood of having to perform two antenna switches. Also while the received signal is buffered, timing recovery and frequency offset correction are performed.

Abstract: A selection diversity system and method for use in a TDMA (time division multiple access) radio system, particularly suited for DECT (Digital Enhanced Cordless Telephone) applications, in which a single receiver makes a performance measurement on each of two antennas in sequence during the beginning of a received data burst, the beginning of the burst being determined by a timing signal fed back from a previous burst. A slicing level used in the receiver to perform threshold detection is continuously improved during the measurements of the two antennas, but held while switching between the antennas. The previously unused antenna is measured first to minimize the likelihood of having to perform two antenna switches.