US 8,570,186 B2 · Wireless sensor reader

Abstract

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.

Claims59

Dependent claims

A wireless sensor reader comprising:

a transmit circuit configured to generate an excitation pulse to cause a wireless sensor to emit a ring signal;
an antenna configured to transmit said excitation pulse and receive said ring signal;
a phase-locked loop circuit configured to receive said ring signal, said phase-locked loop circuit including a voltage-controlled oscillator configured to generate a count signal at a frequency related to said ring signal frequency;
a circuit for identifying a set of possible frequency values of said ring signal for an individual reading;
wherein said phase-locked loop circuit is capable of being placed in a sample mode to receive said ring signal and adjust the frequency of said count signal based on the frequency of said ring signal;
wherein at least one of said transmit circuit, said phase-locked loop circuit, said antenna, and said voltage-controlled oscillator are tunable to the identified set of possible frequency values;
and
further wherein said phase-locked loop circuit is capable of being placed in a hold mode to hold the frequency of said count signal constant for a length of time sufficient to determine the frequency of said count signal.

5 more elements

Dependencies are inferred from the claim text.

Wireless sensor reader

Life of this patent

Wireless sensor reader

Life of this patent

Abstract

Claims59