Periodic signal generators having microelectromechanical resonators therein that support generation of high frequency low-TCF difference signals

摘要

A periodic signal generator is configured to generate high frequency signals characterized by relatively low temperature coefficients of frequency (TCF). A microelectromechanical resonator, such as concave bulk acoustic resonator (CBAR) supporting capacitive and piezoelectric transduction, may be geometrically engineered as a signal generator that produces two periodic signals having unequal resonant frequencies with unequal temperature coefficients. Circuitry is also provided for combining the two periodic signals using a mixer to thereby yield a high frequency low-TCF periodic difference signal at an output of the periodic signal generator.

主权项

1. 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 (f1, f2), said first and second periodic signals characterized by respective first and second temperature coefficients of frequency (TCf1, TCf2) 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 fb equal to f2−Nf1 and a temperature coefficient of frequency (TCfb) of less than a smaller of the absolute value of TCf1 and TCf2.