US Patent 7647028 Internal calibration system for a radio frequency (RF) transmitter

An internal calibration system for a radio frequency (RF) transmitter comprises a digital processing element to generate within a radio frequency (RF) transmitter test points at which an output of the RF transmitter is measured, an RF detector to measure the radio frequency output of the RF transmitter at the test points, the digital processing element also determining transmitter impairments by analyzing the measured radio frequency output, and compensation circuitry to compensate the RF transmitter for the measured impairments.