Patent ID: 9722647
Date: 2017-08-01
CPC Classifications: H03F,H03M,H04B,H04L

Claim:
1. A transceiver front-end circuit for a cellular radio, said transceiver circuit comprising: an antenna operable to transmit signals and receive signals; a switch module including a switching network that directs analog transmit signals to be transmitted to the antenna and receives receive signals from the antenna, said switch module further including a multiplexer module coupled to the switching network and including a plurality of 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; a receiver module including 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 representative digital signals; a transmitter module including a transmitter delta-sigma modulator for converting digital signals to the transmit signals, said transmitter module including a tunable bandpass filter and a power amplifier for amplifying the transmit signals before transmitting; and a calibration feedback and switch module receiving the amplified transmit signals from the power amplifier, said calibration and switch module including a first switch that selectively directs the amplified transmit signals to the antenna or a calibration circuit that determines predistortion values in the transmit signals that are fed back as a calibration feedback signal to the transmitter module to compensate for distortions in the power amplifier.