Patent classifications
H03M3/408
Digital predistortion linearization for power amplifiers
A cellular radio architecture that includes an RF transmitter having a digital signal processor, a digital-to-analog converter (DAC) module that converts digital bits from the processor to an analog signal, a tunable bandpass filter that removes frequencies in the analog signal outside of a frequency band of interest, and a power amplifier that amplifies the filtered analog signal. The architecture also includes a calibration feedback device that receives the amplified analog signal and provides a feedback signal to the processor for calibrating the digital signal to provide amplified amplifier pre-distortion. The processor employs a noise-shaping operation to shape the analog signal from the DAC to remove quantization noise in an immediate vicinity of the signal to improve signal-to-noise ratio, performs an infinite impulse response process to lower a noise floor in the analog signal, and provides pre-distortion of the digital signal to compensate for non-linearties of the power amplifier.
Testing tone free close loop notch frequency calibration for delta-sigma data converters
A cellular radio architecture that includes a receiver module having a delta-sigma modulator that converts analog signals to digital signals and a Fast-Fourier transform (FFT) circuit that converts the digital signals to frequency spectrum signals. The architecture also includes a moving average circuit that smoothes out the frequency spectrum signals by applying a moving average to the signals. The architecture further includes a differentiator circuit that differentiates the frequency spectrum signals to make the signals linear, and a minimum finding circuit that converts the differentiated frequency spectrum signals into positive values for frequencies above a notch frequency in the differentiated signals and negative values for frequencies below the notch frequency in the differentiated signals. A transition between the positive and negative values is compared to a desired notch frequency value, and if the difference is greater than a predetermined threshold, an adaptive control circuit calibrates the modulator.
Calibration techniques for sigma delta transceivers
A cellular radio architecture that includes a transceiver front-end circuit including an antenna and a switch module having a switching network that directs analog transmit signals to be transmitted to the antenna and receives receive signals from the antenna. The architecture further includes a receiver module having a separate signal channel for each of the signal paths in the multiplexer module, where each signal channel in the receiver module includes a receiver delta-sigma modulator that converts analog receive signals to a representative digital signal. The architecture also includes a transmitter module having a transmitter delta-sigma modulator for converting digital data bits to the transmit signals. The transmitter module includes a tunable bandpass filter and a power amplifier for amplifying the transmit signals before transmitting. The architecture also includes a calibration feedback and switch module that receives the amplified signals from the power amplifier.
Performance optimization of power scaled delta sigma modulators using a reconfigurable gm-array
A cellular radio architecture that includes a receiver module having a delta-sigma modulator that includes a plurality of gm cells configured in stages, where each stage includes at least two gm cells and an LC filter circuit. The gm cells in each stage can be controlled to be active or inactive to convert, for example, the modulator from a fourth order modulator to a second order modulator to reduce power dissipation. Further, the gm cells can be controlled to optimize a dynamic range of the modulator and to redirect current from inactive cells to active cells in order to optimize power consumption.
High oversampling ratio dynamic element matching scheme for high dynamic range digital to RF data conversion for radio communication systems
An RF transmitter module for a cellular radio that includes a delta-sigma modulator having a plurality of interleaving dynamic element matching (DEM) circuits providing interleaved digital bits at a reduced clock rate. An interleaver controller controls the DEM circuits so as to provide groups of the digital bits at different points in time. In one embodiment, a summation junction adds the groups of the digital bits to provide a continuous stream of the interleaved digital bits, a DAC converts the stream of interleaved digital bits to an analog signal, and a power amplifier amplifies the analog signal.
DIGITAL PREDISTORTION LINEARIZATION FOR POWER AMPLIFIERS
A cellular radio architecture that includes an RF transmitter having a digital signal processor, a digital-to-analog converter (DAC) module that converts digital bits from the processor to an analog signal, a tunable bandpass filter that removes frequencies in the analog signal outside of a frequency band of interest, and a power amplifier that amplifies the filtered analog signal. The architecture also includes a calibration feedback device that receives the amplified analog signal and provides a feedback signal to the processor for calibrating the digital signal to provide amplified amplifier pre-distortion. The processor employs a noise-shaping operation to shape the analog signal from the DAC to remove quantization noise in an immediate vicinity of the signal to improve signal-to-noise ratio, performs an infinite impulse response process to lower a noise floor in the analog signal, and provides pre-distortion of the digital signal to compensate for non-linearties of the power amplifier.
TESTING TONE FREE CLOSE LOOP NOTCH FREQUENCY CALIBRATION FOR DELTA-SIGMA DATA CONVERTERS
A cellular radio architecture that includes a receiver module having a delta-sigma modulator that converts analog signals to digital signals and a Fast-Fourier transform (FFT) circuit that converts the digital signals to frequency spectrum signals. The architecture also includes a moving average circuit that smoothes out the frequency spectrum signals by applying a moving average to the signals. The architecture further includes a differentiator circuit that differentiates the frequency spectrum signals to make the signals linear, and a minimum finding circuit that converts the differentiated frequency spectrum signals into positive values for frequencies above a notch frequency in the differentiated signals and negative values for frequencies below the notch frequency in the differentiated signals. A transition between the positive and negative values is compared to a desired notch frequency value, and if the difference is greater than a predetermined threshold, an adaptive control circuit calibrates the modulator.
PERFORMANCE OPTIMIZATION OF POWER SCALED DELTA SIGMA MODULATORS USING A RECONFIGURABLE GM-ARRAY
A cellular radio architecture that includes a receiver module having a delta-sigma modulator that includes a plurality of gm cells configured in stages, where each stage includes at least two gm cells and an LC filter circuit. The gm cells in each stage can be controlled to be active or inactive to convert, for example, the modulator from a fourth order modulator to a second order modulator to reduce power dissipation. Further, the gm cells can be controlled to optimize a dynamic range of the modulator and to redirect current from inactive cells to active cells in order to optimize power consumption.
Software programmable cellular radio architecture for telematics and infotainment
A cellular radio architecture for a vehicle that includes a programmable bandpass sampling radio frequency front-end and an optimized digital baseband. The architecture includes a triplexer having signal paths that include a bandpass filter that passes a different frequency band than the other bandpass filters and a circulator that provides signal isolation between the transmit signals and the receive signals. The architecture also includes a receiver module having a separate signal channel for each of the signal paths in the triplexer, where each signal channel in the receiver module includes a receiver delta-sigma modulator that converts analog receive signals to a representative digital signal. The architecture further includes a transmitter module having a transmitter delta-sigma modulator for converting digital data bits to analog transmit signals, where the transmitter module includes a power amplifier and a switch for directing the transmit signals to one of the signal paths in the triplexer.
CALIBRATION TECHNIQUES FOR SIGMA DELTA TRANSCEIVERS
A cellular radio architecture that includes a transceiver front-end circuit including an antenna and a switch module having a switching network that directs analog transmit signals to be transmitted to the antenna and receives receive signals from the antenna. The architecture further includes a receiver module having a separate signal channel for each of the signal paths in the multiplexer module, where each signal channel in the receiver module includes a receiver delta-sigma modulator that converts analog receive signals to a representative digital signal. The architecture also includes a transmitter module having a transmitter delta-sigma modulator for converting digital data bits to the transmit signals. The transmitter module includes a tunable bandpass filter and a power amplifier for amplifying the transmit signals before transmitting. The architecture also includes a calibration feedback and switch module that receives the amplified signals from the power amplifier.