Wireless sensor reader

摘要

A wireless sensor reader is provided to interface with a wireless sensor. The wireless sensor reader transmits an excitation pulse to cause the wireless sensor to generate a ring signal. The wireless sensor reader receives and amplifies the ring signal and sends the signal to a phase-locked loop. A voltage-controlled oscillator in the phase-locked loop locks onto the ring signal frequency and generates a count signal at a frequency related to the ring signal frequency. The voltage-controlled oscillator is placed into a hold mode where the control voltage is maintained constant to allow the count signal frequency to be determined. The reader uses an ambient reading or other information to select a subset of the possible ring signal frequencies, and tunes or adjusts its circuits and algorithms to focus on that subset.

主权项

1. A method of obtaining a measurement from a remote location, the method comprising:
transmitting a plurality of excitation pulses each at a predetermined frequency to a wireless sensor; receiving a signal from said wireless sensor at a reader in response to said plurality of excitation pulses; sampling and holding said received signal; ascertaining the frequency of said received signal; wherein said wireless sensor is configured to change its resonant frequency in proportion to at least one sensed parameter; and wherein said reader is configured to define a band of resonant frequency values, to optimize itself for operation based on said band wherein said reader is in communication with an ambient pressure sensor configured to at least partially define the band of resonant frequency values.