Simplified complex digital sampling demodulator

The process of digital complex sampling can be used to demodulate an IF signal into its baseband quadrature components. Efforts to employ digital complex sampling to generate the I and Q inputs to a digital frequency discriminator resulted in a system whose output contained significant AM sidebands. One of the two pairs of sidebands was caused by a sampling offset introduced by the digital complex sampling technique. The other was produced by the DC content of the input signal. This letter describes the effect of these two problems and presents a solution along with experimental results.