1852results about "Frequency analysis" patented technology

A method for calculating the capacitance of a transducer (C₀) without knowing the exact resonance frequency of a transducer/blade combination is achieved by sweeping across a broad frequency range which contains resonant and non-resonant frequencies where C₀ can be measured. A pre-defined frequency range is set independently of the resonance frequency of a specific transducer/blade combination. C₀ of the transducer/blade is measured at several different frequencies within the pre-defined frequency range to ensure that invalid C₀ measurements are disregarded, and the temperature of the transducer is calculated based on valid C₀ measurements. The determined transducer temperature, based on C₀ measurements, can be used to optimize performance and/or provide a safety shutdown mechanism for the generator.

Provided are an envelope processor 103, for obtaining an envelope for a detected signal; a FFT unit 104, for converting the envelope into a frequency spectrum; a peak detector 105, for smoothing the frequency spectrum by calculating a moving average, for further performing smoothing and differentiation for the spectrum, and detecting, as peaks, frequency points at which a sign of a differential coefficient is changed from positive to negative, for extracting peaks having a predetermined threshold value or greater, and for sorting the extracted peaks and detecting upper peaks; and a diagnosis processor T, for diagnosing an abnormality based on the detected peaks.

Disclosed is a system and method for providing an oscillating signal of relatively precise frequency without using a signal provided by a crystal as a reference. Disclosed is a feedback oscillator circuit configured to output an oscillating signal having a frequency defined by a reference signal. The oscillating signal can be sent to one or more circuits including at least one frequency sensitive element. The frequency sensitive element produces an output signal which depends on the frequency of the oscillating signal. A controller controls the reference signal in order to cause an attribute of the output signal to have a value within a desired range.

Apparatus and methods are provided for analyzing surface characteristics of a test object using broadband scanning interferometry. Test objects amenable to these apparatus and methods include but are not limited to semiconductor wafers, semiconductor devices, metallic surfaces, and the like. An interferometry system is used to obtain an interferometry signal and related to data embodied in the signal representative of the test object surface. This signal and/or data is used to construct an n-dimensional function that includes an independent frequency variable and an independent time variable, and/or an n-dimensional function that includes an independent scale variable and an independent time variable, and/or a multi-domain function. These functions are compared with various models to obtain a best match that is then used to characterize the test object surface.

The present invention includes methods and devices to apply predistortion to correct nonlinearities of a power amplifier in an OFDM symbol transmission system. More particularly, predistortion is patterned to take into account clipping of symbols and to match an effective input range of the predistorter with an average power output of the power amplifier. This invention may be applied to a variety of standards utilizing OFDM technology, including IEEE 802.11a, Hiperlan/2 and MMAC.

A miniature resonating marker assembly that includes, in one embodiment, a ferromagnetic core, a wire coil disposed around the core, and a capacitor connected to the wire coil adjacent to the magnetic core. The core, coil, and capacitor form a signal element that, when energized, generates a magnetic field at a selected resonant frequency. The magnetic field has a magnetic center point positioned along at least one axis of the signal element. An inert encapsulation member encapsulates the signal element therein and defines a geometric shape of the resonating marker assembly. The geometric shape has a geometric center point substantially coincident with the magnetic center point along at least a first axis of the signal element. The shape and configuration of the assembly also provides for a miniature signal element specifically tuned to resonate at a selected frequency with a high quality factor.

The start up performance of an ultrasonic system under zero load conditions is improved by setting a phase set point in a frequency control loop such that, at start up under zero load conditions, the phase set point intersects a point on a phase-frequency response curve which has a low positive slope. This intersection point on the phase-frequency response curve changes as the load is increased and the system Q is decreased. The controller “seeks” a target 0° impedance phase angle. The frequency of the ultrasonic generator is set to an off-resonance frequency which is lower than the resonance of any known hand piece/blade combination. In order for the drive voltage to not exceed the physical limit of the system, the drive current is set to a low level. The drive frequency is then smoothly increased in steps until the target 0° impedance phase delta is located.

Systems and methods for detecting the impedance of an output load coupled to a digital amplifier and compensating for changes in the response of the amplifier. One embodiment of the invention is implemented in a Class D pulse width modulated (PWM) amplifier. In this embodiment, a digital PCM test signal is generated. This test signal is processed by the amplifier to produce a corresponding analog audio output signal that is used to drive a speaker. A sense resistor placed in series with the speaker is used to generate a test voltage that is compared to a reference voltage. When the test voltage reaches the reference voltage, the current through the sense resistor (hence the speaker) is at a known level, so the value of the digital test signal is noted. The impedance of the speaker is then determined from the test signal value and the speaker current.

The invention detects loft time and/or speed of a vehicle and/or person during activities of moving and jumping. A loft sensor detects leaving the ground and returning to the ground. A microprocessor subsystem converts the sensed information to determine a loft time. A display shows the recorded loft time to a user of the system. A speed sensor can detect speed for selective display to the user, and height may also be determined during airtime.

Transmitter (116) designed to automatically reconfigure one or more circuit parameters associated with an RF power amplifier (210) in response to certain user input commands. Specifically, a transmitter circuit configuration is automatically modified under certain conditions to produce a higher RF output power. The higher RF power output is possible because the transmitter configuration is adjusted specifically for use under a particular set of operating conditions. The operating conditions that trigger the higher powered configuration include burst transmission mode.

A system for conducting performing real-time harmonics analysis of an electrical power distribution and transmission system is disclosed. The system includes a data acquisition component, a power analytics server and a client terminal. The data acquisition component is communicatively connected to a sensor configured to acquire real-time data output from the electrical system. The power analytics server is communicatively connected to the data acquisition component and is comprised of a virtual system modeling engine, an analytics engine and a machine learning engine. The machine learning engine is configured to store and process patterns observed from the real-time data output and the predicted data output, forecasting harmonic distortions in the electrical system subjected to a simulated contingency event.

One or more median filter circuits are used to filter radio link control measurements corresponding to one or more radio link parameters of interest, such as received signal quality or round trip delay measurements, such as might be used by a base station to trigger mobile station handoff. As such measurements are particularly susceptible to measurement outliers arising from rapid but short-lived changes in radio link propagation paths, for example, the application of median filtering to such measurements is particularly advantageous. That is, by operation of median filtering, which is a non-linear filtering process, outliers in a stream of control measurements, such as are caused by instantaneous changes in channel fading or other propagation phenomena, are discarded rather than averaged in with the other measurements. Non-linear filtering as implemented by exemplary median filtering does not impair or otherwise limit the bandwidth of the underlying control measurements.

A data system 102 permits bus encoding based on frequency of the bus; an encoding scheme may be implemented to avoid undesirable frequency conditions such as a resonant condition that may lead to degradation in system performance. The device or integrated circuit will typically include an encoder; in one embodiment, the encoder is a data bus inversion (DBI) circuit that selectively inverts all lines of a data bus. A detector that may include a band-pass or stop-band filter that, for example, evaluates data for transmission on the bus to detect frequency, for example, a predetermined frequency or a frequency range. The detector provides a control signal for the encoder to selectively apply an encoding scheme as a function of frequency.

A method and circuit for measuring a statistical value of jitter for a data signal having a data rate f_D, comprises digitally sampling the data signal at a sampling rate, f_S, to produce sampled logic values, where f_D/f_S is a predetermined non-integer ratio; and analyzing the sampled values to deduce a statistical value of the jitter.

A personal alerting device and method for detecting an approaching sound source includes a sound detector for detecting environmental sounds and for providing an electrical signal to a sound analyzer. The sound signal is analyzed to determine a baseline sound pattern comprising a plurality of distinct sounds corresponding to sounds emitted from a reference sound source. The distinct sounds in the baseline sound pattern may have substantially the same amplitude and time interval. The sound signal is monitored and compared against the baseline sound pattern to determine whether a target sound pattern is present in the sound signal, the target sound pattern corresponding to sounds emitted by the approaching sound source. When it is determined that the target sound is present in the sound signal, one or more of an audible, visual and tactile alert may be emitted to provide warning of the approaching sound source.

The invention discloses a harmonic amplitude measurement method and system of a power signal. The method comprises the following steps: performing digital filtering on an imaginary vector sequence and a real vector sequence to generate an imaginary vector filter sequence and a real vector filter sequence; equally dividing the real vector filter sequence and the imaginary vector filter sequence into two sections of sequences to generate a real vector filter front-section sequence, a real vector filter rear-section sequence, an imaginary vector filter front-section sequence and an imaginary vector filter rear-section sequence respectively; integrating the real vector filter front-section sequence, the imaginary vector filter front-section sequence, the real vector filter rear-section sequence and the imaginary vector filter rear-section sequence in sequence to solve phase and phase difference; converting the phase difference and reference frequency into fundamental wave frequency of the power signal. The product of the fundamental wave frequency and a harmonic factor is used as the reference frequency to perform harmonic wave amplitude measurement. By implementing the method and the system, mixed frequency interference elements in the imaginary vector sequences and the real vector sequences can be inhibited to generate the harmonic wave amplitude with high precision.

A pressure-sensitive capacitive sensor includes a sensing unit in which a plurality of column wires and a plurality of row wires are formed in a matrix, a detecting signal generator, and filters. Capacitances at intersections between the column wires and the row wires change in accordance with externally applied pressure. The detecting signal generator sequentially outputs pulse signals of a predetermined frequency to the column wires of the sensing unit. The filters are connected to the respective row wires of the sensing unit and extract amplitudes of signals of the predetermined frequency. The amplitude is proportional to the capacitance at the intersection.

A stabilized field sensor apparatus collects field data, in particular magnetic field data, with reduced motion noise. The apparatus includes a tear drop shaped housing, a tow frame in the housing, a plurality of vibration isolating dampers spaced around the frame, a base assembly mounted to the dampers, a support pedestal having a bottom end fixed to the base assembly and an upper free end, a single spherical air bearing connected to the upper free end of the pedestal, an instrument platform with a lower hollow funnel having an upper inside apex supported on the air bearing for a one point support, principal and secondary gyro stabilizers for maintaining pivotal and rotational stability, and at least one field sensor mounted to the instrument platform for collecting the field data while being stabilized against motion noise including vibration, pivoting and rotation from the base assembly, from the tow frame and from the housing. Stabilization of the instrument platform is enhanced by preserving accurate balance through a dynamic balancing system whereby small masses are moved under computer control to maintain the center of mass of the instrument platform at the center of rotation of the spherical air bearing. The dynamic stabilization process is made more precise by actively vibrating the instrument platform by a set of linear vibrators.

Disclosed is an apparatus and method for modeling and estimating the characteristics of a power amplifier with memory. A predistortion module generates a predistorted signal in response to coefficients of a complex polynomial representative of the amplifier and to an input signal. A power amplifier receives time-spaced samples of the predistorted signal and generates an output signal. A polynomial module updates the coefficients of the complex polynomial in response to a current sample of the output signal and to the time-spaced samples of the predistorted signal. In particular, the complex polynomial is implemented with both even and odd terms.

Embodiments of the present invention provide a method of centering an operating band of a voltage controlled oscillator around a desired operating frequency. In one embodiment, an adjustable feedback divider provides for driving an output signal to the top and bottom of the operating band. An adjustable period divider and counter provide a plurality of count values for use in determining a mid-point of the operating band. A capacitance bank provides for selectively adjusting a capacitance of the voltage controlled oscillator, thereby adjusting the operating band.