1871results about "Frequency analysis" patented technology

Several open-loop calibration techniques for phase-locked-loop circuits (PLL) that provide a process, temperature and divider modulus independence for the loop bandwidth and damping factor are disclosed. Two categories of open-loop techniques are presented. The first method uses only a single measurement of the output frequency from the oscillator and adjusts a single PLL loop element that performs a simultaneous calibration of both the loop bandwidth and damping factor. The output frequency is measured for a given value of the oscillator control signal and the charge-pump current is adjusted such that it cancels the process variation of the oscillator gain. The second method uses two separate and orthogonal calibration steps, both of them based on the measurement of the output frequency from the oscillator when a known excitation is applied to the open loop signal path. In the first step the loop bandwidth is calibrated by adjusting the charge-pump current based on the measurement of the forward path gain when applying a constant phase shift between the two clocks that go to the phase frequency detector, while the integral path is hold to a constant value. During the second step the damping factor is calibrated by adjusting the value of the integral loop filter capacitor based on the measurement of the oscillator output frequency when excited with a voltage proportional with the integral capacitor value, while the proportional control component is zeroed-out.

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 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.

A system for acquiring an ultrasound signal comprises a signal processing unit adapted for acquiring a received ultrasound signal from an ultrasound transducer having a plurality of elements. The system is adapted to receive ultrasound signals having a frequency of at least 20 megahertz (MHz) with a transducer having a field of view of at least 5.0 millimeters (mm) at a frame rate of at least 20 frames per second (fps). The signal processing can further produce an ultrasound image from the acquired ultrasound signal. The transducer can be a linear array transducer, a phased array transducer, a two-dimensional (2-D) array transducer, or a curved array transducer.

A method and an algorithm allowing the use of surface waves. In particular, the method uses separation of the modes and, by the dispersion curve of more than one mode in the inversion process, it allows a determination of a shear wave propagation velocity profile that, with the aid of the Poisson ratio, constitutes a unique solution and a complete characterization of a medium on the point of view of its elastic properties.