Oscillator Phase Noise Suppression in Surface Acoustic Wave Sensor Systems

Journal
IEEE sensors journal  
Volume
18
Issue
12
Start Page
4975
End Page
4980
Citation
IEEE Sensors Journal 18 (12): 4975-4980 (2018-06-15)
Publisher DOI
10.1109/JSEN.2018.2832289
Scopus ID
2-s2.0-85046347870
Surface acoustic wave (SAW) sensors are widely used in different fields of application. In order to maximize the limit of detection of such sensor systems, it is of high importance to understand and to be able to quantify the relevant noise sources. A straightforward approach to detect the desired phase information of SAW sensors is to compare the sensor output signal with a reference signal. In this paper, the effect of decorrelation of oscillator phase noise as a function of delay time and offset frequency is discussed and analyzed. An analytical expression is derived which describes the degree of phase noise suppression in heterodyne readout systems. The model is verified by various measurement series, showing a degree of phase noise suppression of -100 dB for an offset frequency of 1 Hz and for a decorrelation time of 1500 ns which represents a typical time delay of SAW sensors. Although the effect is analyzed with respect to SAW sensors, the results are basically applicable to all kinds of phase sensitive sensors.
Subjects
Decorrelation time
oscillator phase noise suppression
phase detection
readout systems
SAW
time-delaying sensors