This disclosure describes a chopper mixer telemetry circuit for use in a wireless receiver. The receiver may be located in an implantable medical device (IMD) or external programmer. The chopper mixer telemetry circuit may include a mixer amplifier that operates as a synchronous demodulator to provide selective extraction of wireless signals received from a transmitter while suppressing out-of-band noise that can undermine the reliability of the telemetry link between an IMD or programmer and another device. The mixer amplifier may utilize parallel signal paths to convert the received telemetry signal into an in-phase (I) signal component and a quadrature (Q) signal component and recombine the I and Q signal components to reconstruct the total signal independently of the phase mismatch between the transmitter and receiver. Each signal path may include a chopper-stabilized mixer amplifier that amplifies telemetry signals within a desired band while suppressing out-of-band noise.
