Sensor for sensing substances in an environment

Abstract

There is set forth herein a sensor for sensing of substances. The sensor can include a sensing crystal oscillator and a reference crystal oscillator. The sensing crystal oscillator and the reference crystal oscillator can be arranged in a phase locked loop so that the oscillators oscillate at a common frequency. The sensor can be configured so that there is a baseline phase differential between the oscillation frequencies of the sensing crystal oscillator and the reference crystal oscillator. Detectable substances accumulating on the sensing crystal oscillator will induce a phase shift between output frequencies of the reference oscillator and the sensing crystal oscillator to allow for highly sensitive sensing of substances in small concentrations.

Dependencies are inferred from the claim text.