An apparatus comprises: a first oscillator circuit having a first terminal and a second terminal; a second oscillator circuit having a third terminal and a fourth terminal; a first circuit having a first positive input, a first negative input, a first positive output, and a first negative output, the first positive input coupled to the first terminal, the first negative input coupled to the second terminal, the first positive output coupled to the third terminal, and the first negative output coupled to the fourth terminal; and a second circuit having a second positive input, a second negative input, a second positive output, and a second negative output, the second positive input coupled to the fourth terminal, the second negative input coupled to the third terminal, the second positive output coupled to the first terminal, and the second negative output coupled to the second terminal.

In one aspect, the disclosure relates to a super high frequency (SHF) or extremely high frequency (EHF) bulk acoustic resonator that includes a nanostructure, wherein the nanostructure includes a substrate, a three-dimensional structure disposed on the substrate, wherein the three-dimensional structure includes a planar structure including at least one nanocomponent and a matrix material contacting the nanocomponent on at least one side, the matrix material including an SiGe alloy or Ge. The disclosed bulk acoustic resonator operates at frequencies of from about 100 MHz to about 100 GHz, is capable of self-amplification upon application of direct current or voltage, and has a Q factor amplification exceeding 1. Also disclosed are methods for amplification of mechanical resonance in the disclosed bulk acoustic resonators and devices incorporating the bulk acoustic resonators.

An integrated circuit may include oscillator circuitry having a resonator formed from fin field-effect transistor (FinFET) devices. The resonator may include drive cells of alternating polarities and sense cells interposed between the drive cells. The resonator may be connected in a feedback loop within the oscillator circuitry. The oscillator circuitry may include an amplifier having an input coupled to the sense cells and an output coupled to the drive cells. The oscillator circuitry may also include a separate inductor and capacitor based oscillator, where the resonator serves as a separate output filter stage for the inductor and capacitor based oscillator.

Techniques for improving acoustic resonators and resonator structures are disclosed, including filters, oscillators and systems that may include such devices. A bulk acoustic wave (BAW) resonator may comprise a substrate. The bulk acoustic wave (BAW) may further comprise a plurality of piezoelectric layers including first, second, third and fourth piezoelectric layers acoustically coupled with one another and arranged over the substrate. The first, second, third and fourth piezoelectric layers may have respective piezoelectric axis orientations. The first, second, third and fourth piezoelectric layers may have respective thicknesses. Electromechanical coupling of the bulk acoustic wave (BAW) resonator may, but need not be limited.

A circuit device includes: a first terminal and a second terminal coupled to a resonator; a third terminal; a fourth terminal; a first switch provided on a signal path between the first terminal and the third terminal; a second switch provided on a signal path between the second terminal and the fourth terminal; and a register configured to output a signal for controlling the first switch and the second switch to be turned on or off. In a first mode, the first switch and the second switch are turned off, a control signal is input to the third terminal, and a clock signal is output from the fourth terminal. In a second mode, the first switch and the second switch are turned on.

Aspects of the disclosure provide a method of using a bulk acoustic wave (BAW) based clock. For example, a first burst pulse of ultrasonic waves may be received by a transmit transducer of a BAW delay device. A feedthrough pulse from the first burst pulse may be received at a receive transducer of the BAW delay device. After receiving the feedthrough pulse, a first echo pulse from the first burst pulse may be received at the receive transducer. The first pulse may be a reflection of a portion of the first burst pulse from a substrate. A difference in time between the receipt of the feedthrough pulse and the receipt of the first echo pulse may be used to control timing of a second burst pulse of ultrasonic waves.

Aspects of the disclosure provide a method of using a bulk acoustic wave (BAW) based clock. For example, a first burst pulse of ultrasonic waves may be received by a transmit transducer of a BAW delay device. A feedthrough pulse from the first burst pulse may be received at a receive transducer of the BAW delay device. After receiving the feedthrough pulse, a first echo pulse from the first burst pulse may be received at the receive transducer. The first pulse may be a reflection of a portion of the first burst pulse from a substrate. A difference in time between the receipt of the feedthrough pulse and the receipt of the first echo pulse may be used to control timing of a second burst pulse of ultrasonic waves.

In one example, an apparatus comprises an oscillator having a control input and a clock output. The apparatus also comprises a frequency control circuit having an input and a control output, the control output coupled to the control input, and a reference clock generator having a reference clock output. The apparatus also comprises a multiplexer having a first multiplexer input, a second multiplexer input, a selection input, and a multiplexer output, the first multiplexer input coupled to the clock output, the second multiplexer input coupled to the reference clock output, and the multiplexer output coupled to the input of the frequency control circuit.