A system and method are provided for compensating for an I/Q mismatch of a
receiver in a mobile terminal. In general, the receiver and a transmitter
of the mobile terminal are formed on a single substrate. A transmit
signal is transmitted via the transmitter. Due to leakage through the
substrate, the transmit signal is provided to one or more points in the
receiver. One of these points is an input of the amplifier circuitry. A
gain of the amplifier circuitry is modulated during reception of the
transmit signal such that an amplified signal provided by the amplifier
circuitry is offset from the carrier frequency of the transmit signal by
a known frequency offset. The amplified signal is downconverted to
provide a quadrature output signal. Processing circuitry processes
frequency components of the quadrature output signal corresponding to the
known frequency offset to determine the I/Q mismatch of the receiver.