Arrangement for and method of concurrent quadrature downconversion input sampling of a bandpass signal

摘要

An arrangement for generating a digital, downconverted complex baseband signal from a bandpass signal comprises a signal source for providing first and second clock signals at first and second clocking rates, respectively. The first clocking rate is at four times the expected center frequency of the bandpass signal, and the second clocking rate is at an exact subharmonic frequency of the bandpass frequency. The bandpass signal is sampled by a composite sampling event of two sampling pulses which occur once during each period of the second clocking signals and which are time-spaced from each other by the inverse of the first clocking rate. The complex baseband samples are ready as an A/D converter output, with no requirement for DSP processing to complete the downconversion to zero-IF.