Apple Inc.
Self-Evaluating High Frequency, Bandwidth, And Dynamic Range Cellular Polar Transmit Signal Fidelity

Abstract:

A radio communication device includes a device substrate. A transmitter circuit is coupled to the device substrate to transmit a radio frequency signal to an antenna. The radio communication device also includes a receiver circuit coupled to the device substrate, where the receiver circuit includes an oscillator circuit to generate a baseband signal from a received radio frequency signal. The radio communication device further includes a feedback circuit coupled to the antenna and to the receiver circuit, where the feedback circuit couples a portion of the transmitted radio frequency signal to the oscillator circuit using a transmission line.