摘要:
An apparatus and method for detecting a target environmental variable (TEV). A first film-bulk acoustic resonator (FBAR) oscillator that includes a first FBAR with a first response to the target environmental variable generates a first frequency. A second film-bulk acoustic resonator (FBAR) oscillator that includes a second FBAR with a second response to the target environmental variable generates a second frequency. A circuit that is coupled to the first FBAR oscillator and the second FBAR oscillator determines the target environmental variable (e.g., changes in the TEV) based on the first frequency and the second frequency.
摘要:
An apparatus and method for measuring a target environmental variable (TEV) that employs a film-bulk acoustic resonator with motion plate. The film-bulk acoustic resonator (FBAR) includes an acoustic reflector formed in an FBAR wafer and a surface. A first electrode is formed on the surface of the acoustic reflector and has a surface. A piezoelectric layer is formed on the surface of the first electrode and has a surface. A second electrode is formed on the surface of the piezoelectric layer. A motion plate is suspended in space at a predetermined distance relative to the surface of the second electrode and is capacitively coupled to the FBAR.
摘要:
A sensor senses an environmental condition. The sensor includes a film bulk acoustic resonator that includes a layer of material that causes resonant frequency and/or quality factor shifts of the film bulk acoustic resonator in response to changes in the environmental condition. The environmental condition may be relative humidity and the layer of material may be a moisture absorptive material.
摘要:
A spread-spectrum radio, such as a frequency-hopping spread-spectrum radio or a direct-sequence spread-spectrum radio, includes a transmitter that utilizes microelectromechanical systems (MEMS) based oscillation system to generate a spread-spectrum signal and/or a receiver that utilizes a MEMS-based frequency selection system to receive a spread-spectrum signal. In an embodiment, the MEMS-based oscillation system and the MEMS-based frequency selection system utilize MEMS resonators such as thin film bulk acoustic resonators (FBARs) that are fabricated in high density on a single substrate.
摘要:
A sensor senses an environmental condition. The sensor includes a film bulk acoustic resonator that includes a layer of material that causes resonant frequency and/or quality factor shifts of the film bulk acoustic resonator in response to changes in the environmental condition. The environmental condition may be relative humidity and the layer of material may be a moisture absorptive material.
摘要:
A multiplexer for use with switching apparatus for data communication networks. The multiplexer topology includes two or more groupings, or sections, each containing a plurality of individual channels. Each of the channels has an input buffer amplifier and an output Ft-doubler circuit. The outputs of all of the channels within a each particular channel section are connected in parallel relation, and fed to respective common-base transistor amplifiers. The outputs of all of the common-base amplifiers for each channel section, in turn, are connected in parallel and fed to the inputs of a pair of emitter-follower amplifiers. Through the use of selectively actuated current sources, each multiplexer channel is normally biased off, unless that channel is selected for a switching operation. Bleeder current sources are applied to the emitters of the common-base amplifiers to reduce output jitter from the channels which are biased off. The multiplexer architecture provides high speed operation from channel sectioning, and low power consumption by reducing both the amount of current drawn and the voltage potential necessary, to operate the multiplexer.
摘要:
A symmetrical photo-amplifier circuit with improved power supply rejection includes a signal circuit and a reference circuit, in which the electrical capacitances and parasitic capacitances from mechanical sources, such as bond wires and substrates, are matched between the signal circuit and the reference circuit.