Title :
Microcontroller-Based Temperature Compensation Scheme for Two-Port SAW Oscillators
Author :
Roith, Bernd ; Gollwitzer, Andreas ; Lerner, Andreas ; Fischerauer, Gerhard
Author_Institution :
Meas. & Control Eng., Bayreuth Univ.
Abstract :
We present a surface acoustic wave (SAW) two-port oscillator extended by a feedforward control circuit, the goal of which is to suppress the effects of the SAW resonator temperature characteristics on the oscillator output frequency. The control circuit consists of a temperature sensor near the SAW resonator the output signal of which is fed to the analog-to-digital converter (ADC) input of a microcontroller. An algorithm implemented on the microcontroller combines the information on the actual temperature and the temperature behavior of all oscillator components (known from previous measurement campaigns) to determine a compensation signal. The latter is fed to a phase shifter inserted in the oscillator feedback loop such that any temperature-induced changes in the round-trip phase shift of the oscillator loop are counteracted. An improvement factor in the frequency stability of 4.4 was demonstrated in the temperature range from 0 to 60 degC and can be further improved to a value of at least 10
Keywords :
compensation; frequency stability; microcontrollers; phase shifters; surface acoustic wave oscillators; surface acoustic wave resonators; temperature sensors; two-port networks; 0 to 60 C; SAW resonator; analog-to-digital converter; feedforward control circuit; frequency stability; microcontroller-based temperature compensation scheme surface acoustic wave two-port oscillator; oscillator feedback loop; phase shifter; temperature sensor; Acoustic waves; Analog-digital conversion; Circuits; Frequency; Microcontrollers; Oscillators; Phase shifters; Surface acoustic waves; Temperature control; Temperature sensors;
Conference_Titel :
International Frequency Control Symposium and Exposition, 2006 IEEE
Conference_Location :
Miami, FL
Print_ISBN :
1-4244-0074-0
Electronic_ISBN :
1-4244-0074-0
DOI :
10.1109/FREQ.2006.275496