Frequency offset correction in transmitters and receivers having non-ideal synthesizer channel spacing

摘要

In a receiver of a transmission system in which the data transmission rate is not an integer multiple of the spacing between transmission channels, a single oscillator is used to generate both the system clock used to process the data signal as well as the mixing signal used to downconvert the received RF signal to an intermediate frequency (IF). The frequency error in the IF signal that results from mixing the RF signal at a less-than-ideal mixing frequency is compensated by selecting an appropriate mixing signal frequency applied when downconverting the IF signal to baseband. In a transmitter, the mixing signal frequency used to upconvert the outgoing baseband signal to IF is selected to pre-compensate for the frequency error resulting from upconverting the IF signal to RF using a less-than-ideal mixing frequency. In either case, the receiver/transmitter can be implemented without having to provide a dedicated reference oscillator for converting signals between RF and IF.