A radio frequency (RF) circuit includes an input terminal configured to receive a reception signal from an antenna; an output terminal configured to output a digital output signal; a receive path including a mixer and an analog-to-digital converter (ADC), wherein the receive path is coupled to and between the input and output terminals, wherein the receive path includes an analog portion and a digital portion, and wherein the ADC generates a digital signal based on an analog signal received from the analog portion; a test signal generator configured to generate an analog test signal injected into the analog portion of the receive path; and a digital processor configured to receive a digital test signal from the digital portion, the digital test signal being derived from the analog test signal, analyze a frequency spectrum of the digital test signal, and determine a quality of the digital test signal.