SOFTWARE PROGRAMMABLE, MULTI-SEGMENT CAPTURE BANDWIDTH, DELTA-SIGMA MODULATORS FOR FLEXIBLE RADIO COMMUNICATION SYSTEMS

摘要

A cellular radio architecture that includes a multiplexer coupled to an antenna structure and including multiple signal paths, where each signal path includes 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 multiplexer, 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 delta-sigma modulator includes an LC filter having a plurality of LC resonator circuits, a plurality of transconductance amplifiers and a plurality of integrator circuits, where a combination of one resonator circuit, transconductance amplifier and integrator circuit represents a two-order stage of the LC filter.