UC Irvine

The influence on the final phase and amplitude determination of the phase noise of frequency synthesizers used in frequency-domain fluorometry is analyzed. It is shown that the phase noise exactly cancels out due to the differential method used for the phase measurement. The only consequence of the phase noise is the detuning of the cross-correlation frequency with respect to the center of the filter used to analyze the cross-correlation signal. This detuning can have severe adverse effects on the phase and modulation values. By using higher values of the cross-correlation frequency, these effects can be minimized. The performance of different synthesizers is tested and compared. The results support the general prediction that the noise of the synthesizer has little influence on the phase noise of actual measurements.