Patent ID: 8742854

Claim:
A periodic signal generator, comprising: an oscillator comprising a microelectromechanical bulk acoustic resonator having a piezoelectric layer therein and drive and sense electrodes on the piezoelectric layer, said oscillator configured to generate first and second periodic signals having unequal first and second frequencies (f 1 , f 2 ), said first and second periodic signals characterized by respective first and second temperature coefficients of frequency (TCf 1 , TCf 2 ) that differ by at least about 10 ppm/° C.; a frequency multiplier responsive to the first periodic signal, said frequency multiplier configured to generate a periodic output signal having a frequency equal to N times a frequency of the first periodic signal, where N is a real number greater than one; and a mixer circuit configured to generate a periodic beat signal in response to the second periodic signal and the periodic output signal, said periodic beat signal having a frequency f b equal to f 2 −Nf 1 and a temperature coefficient of frequency (TCf b ) of less than a smaller of the absolute value of TCf 1 and TCf 2 .