Resolution in quartz crystal oscillator circuits for high sensitivity microbalance sensors in damping media
The use of quartz crystal oscillators as high sensitivity microbalance sensors is limited by the frequency noise present in the circuit. To characterise the behaviour of the sensors, it is not enough to determine their experimental sensitivity, but...
more
Full text:
|
|
Link for citation:
|
|
The use of quartz crystal oscillators as high sensitivity microbalance sensors is limited by the frequency noise present in the circuit. To characterise the behaviour of the sensors, it is not enough to determine their experimental sensitivity, but rather it is essential to study the frequency fluctuations in order to establish the sensor resolution. This is fundamental in the case of oscillators for damping media, because the level of noise rises due to the strong decline of the quality factor of the resonator.
|
Design Considerations of Miller Oscillators for High-Sensitivity QCM Sensors in Damping Media
International audience ; In this paper, a new contribution to the design of quartz crystal oscillators for high-sensitivity microbalance sensors used in liquid media is presented. The oscillation condition for a Miller configuration was studied to...
more
Full text:
|
|
Link for citation:
|
|
International audience ; In this paper, a new contribution to the design of quartz crystal oscillators for high-sensitivity microbalance sensors used in liquid media is presented. The oscillation condition for a Miller configuration was studied to work in a wide dynamic range of the resonator losses. The equations relating the values of the active and passive components with the maximum supported damping and mass were obtained. Also, the conditions to obtain a stable frequency according to the resonator damping (R Q ), the static capacity (C p ) and the filter frequency (f F ) were found. Under these conditions, the circuit oscillation frequency will be proportional to the resonant series frequency and does not depend on the previous parameters (R Q , f F , and C p ). If these conditions cannot be satisfied, the expression of the oscillation frequency is given and the discrimination of these effects is obtained through resonator frequency measurements.
|