Patent ID: 8643440

Claim:
A sensor system comprising: an electric circuit including: a reference signal generation circuit that generates a reference signal based on a first oscillation signal, the first oscillation signal being an oscillation signal of a first oscillation circuit that vibrates a first vibrator; and a counter circuit that counts a second oscillation, the counter circuit counting the second oscillation signal based on the reference signal, the second oscillation signal being an oscillation signal of a second oscillation circuit that vibrates a second vibrator, the counter circuit outputs a count signal, the count signal being based on a change of frequency of the second oscillation signal; wherein the counter circuit further includes an initial stage counter circuit that counts a pulse number of the second oscillation signal, a latch circuit that obtains a count value of the initial stage counter circuit synchronizing with the reference signal, and an operation circuit that calculates a difference between a first count value newly obtained by the latch circuit and a second count value previously obtained by the latch circuit, and outputs the difference as the count signal; a database that is input relations between changes of the frequency of the second oscillation signal and a plurality of substances contained in a medium existing around the second vibrator; and a data processing circuit that specifies one of the plurality of substances contained in the medium based on a serial signal output from the electric circuit and the database, wherein the count signal output from the counter circuit is a parallel signal, and further comprising a parallel-serial converter circuit that converts the count signal to the serial signal and outputs the serial signal.