Abstract: An AC-DC converter, comprises: a first capacitor and a second capacitor; and a rectifier circuit connected to the first and second capacitor and operative to charge both the first and the second capacitor and to discharge the first capacitor independently of the second capacitor. The AC-DC converter circuit provides a rectified output voltage, and a duration of time that a current is drawn from the second capacitor is less than approximately 25% of a period of the rectified output voltage.

Abstract: Systems and methods of detecting wireless channel status from acoustic discrimination of spectral content are described. In one aspect, a wireless system includes a spectrum analyzer, a detector, and a controller. The spectrum analyzer is operable to acoustically discriminate spectral content of an input electrical signal in multiple discrete frequency channels. The detector is operable to determine respective statuses of the frequency channels from the acoustically discriminated spectral content. The controller is operable to select one of the frequency channels based on the determined statuses of the frequency channels.

Abstract: An AC-DC converter and a power supply are described.

Abstract: A power supply comprises an AC-DC converter circuit, which comprises a first capacitor and a second capacitor. The converter also comprises a rectifier circuit connected to the first and second capacitor and operative to charge both the first and the second capacitor and to discharge the first capacitor independently of the second capacitor. The power supply also comprises an acoustic transformer.

Abstract: An AC-DC converter and a power supply are described.

Abstract: An integrated power supply, an integrated battery charger and a portable electronic device with an integrated power supply are described.

Abstract: An integrated power adapter, a portable electronic device with an integrated power adapter, and multichip modules are described.

Abstract: A data coupler includes first and second acoustic isolation transformers that develop first and second isolated output signals in response to first and second modulated input signals. A first and a second transmitter is coupled to the first and second acoustic isolation transformers to receive a first and a second data input signal and generate the first and second modulated input signal in response to the first and second data input signals. A first and a second receiver is coupled to the first and second acoustic isolation transformers to receive the first and a second isolated output signals and generate first and second demodulated signals responsive to the first and second isolated output signals. An output decision circuit is coupled to the first and second receivers to receive the first and second data output signals and generates a data output signal responsive to the first and second demodulated signals.

Abstract: A data coupler includes an acoustic isolation transformer operable to develop an isolated output signal in response to an input signal. A transmitter is coupled to the acoustic isolation transformer and generates the input signal responsive to a data input signal. A receiver is coupled to the acoustic isolation transformer to receive the isolated output signal and generates a data output signal responsive to the isolated output signal.

Abstract: A navigation system including a first navigation sensor configured to provide a first set of positional capacitance values, a second navigation sensor configured to provide a second set of positional capacitance values, and a controller configured to select between the first and second sets of positional capacitance values and to provide navigation information selectively based on the first and second sets of positional capacitance values.

Abstract: 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.

Abstract: A first and a second resonator are fabricated monolithically adjacent to one another. The first resonator is the reference resonator. The resonant frequency of the second resonator is offset by a difference frequency Fo from the first resonator. Each resonator is included within an oscillator. A mixer receives the output of both oscillators. A low pass filter receives the mixer output and generates a clock signal whose frequency is equal to the difference frequency Fo.

Abstract: Systems and methods of detecting wireless channel status from acoustic discrimination of spectral content are described. In one aspect, a wireless system includes a spectrum analyzer, a detector, and a controller. The spectrum analyzer is operable to acoustically discriminate spectral content of an input electrical signal in multiple discrete frequency channels. The detector is operable to determine respective statuses of the frequency channels from the acoustically discriminated spectral content. The controller is operable to select one of the frequency channels based on the determined statuses of the frequency channels.

Abstract: A humidity sensor that includes a resonant structure and a structure for altering a resonant frequency of the resonant structure in response to a change in humidity. The structures of a humidity sensor according to the present teachings may be formed in relatively small form factors and are well suited to remote applications and providing mechanisms for compensating for temperature drift.

Abstract: 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.

Abstract: 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.

Abstract: A method and apparatus for detecting a location of an eye of a user using an automated detection process, and automatically determining a position of a head of the user with respect to an object based on the detected location of the eye. A location of an eye of a user inside a vehicle is detected using the automated detection process, at least one of height and orientation information of the user is automatically determined based on the detected location of the eye, and a mechanical device inside the vehicle is controlled in accordance with the determined information. Moreover, an eye blinking pattern of a user is detected using an infrared reflectivity of an eye of the user, and messages are transmitted from the user in accordance with the detected eye blinking pattern of the user.

Abstract: An autostereoscopic display system includes an autostereoscopic display subsystem operable to display stereoscopic images and to adjust characteristics of the displayed images responsive to detected viewer eye position parameters. An eye detection subsystem detects through differential-angle illumination the eye position of a viewer positioned in front of the display subsystem and generates corresponding viewer eye position parameters. The eye detection subsystem applies the detected viewer eye position parameters the display subsystem to adjust the characteristics of the displayed images.

Abstract: A piezoelectric cantilever pressure sensor has a substrate and a piezoelectric cantilever having a base portion attached to the substrate and a beam portion suspended over a cavity. The piezoelectric cantilever contains a piezoelectric layer sandwiched between two electrodes and generates a measurable voltage when deformed under pressure. The piezoelectric cantilever pressure sensor can be manufactured at low cost and used in various applications including fingerprint identification devices.

Abstract: A demodulator with a filter having a reduced number of filter taps without a sacrifice in filter accuracy. The demodulator includes elements that generate a data stream that carries a component of an input signal in response to a data stream that carries samples of the input signal. The demodulator also includes elements that generate a sample clock for sampling the input signal such that the sample clock is preselected to cause the data stream that carries the component to carry alternating samples that are substantially equal to zero. The filter in the demodulator has a set of filter taps which are arranged to tap only the samples in the data stream that carries the component that are not substantially equal to zero.