ROWLAND, HARRY,WATKINS, ROGER,SUNDARAM, BALAMURUGAN,PAUL, BRYAN,AHN, IN SOO,NAGY, MICHAEL
申请号：
CA2757952
公开号：
CA2757952C
申请日:
2010.03.19
申请国别(地区):
CA
年份:
2017
代理人:
摘要：
A wireless sensor reader ispro-vided to interface with a wireless sensor. Thewireless sensor reader transmits a narrowband,fixed frequency excitation pulse to cause thewireless sensor to generate a ring signal. Thering signal corresponds to the value of thephys-ical parameter being sensed. The wirelesssen-sor reader receives and amplifies the ring signaland sends the signal to a phase-locked loop. Avoltage- controlled oscillator in thephase--locked loop locks onto the ring signal frequencyand generates a count signal at a frequencyre-lated to the ring signal frequency. Thevoltage--controlled oscillator is placed into a hold modewhere the control voltage is maintainedcon-stant to allow the count signal frequency to bedetermined. The low power, simple circuitryre-quired to generate the excitation pulse allowsthe reader to be a small, battery operated unit.Alternative methods of frequency determinationare also disclosed.
