Abstract: Described is a technology by which GPS-capable devices work with a cloud service to receive satellite visibility-related data. The satellite visibility-related data may be used to determine a location, and/or to abort a search for satellites. The cloud service may use crowd data from other GPS-capable devices. In one aspect, line-of-sight satellites are differentiated from other satellites, and used to determine which satellite signals are more trustworthy. Reflected signals also may be determined.

Abstract: System and method for identifying tones present in a short segment of digitized music stream, and for reporting simultaneously and quantitatively their respective magnitude and phase in near real time. Also captured are pitch deviations from the nominal tones of a predetermined music scale. The resulting spectral data can be scrolled manually from frame to frame to facilitate detail music evaluation and editing. The apparatus can also operate at real time to display notes being played, or to tone-activate audio-visual music enhancement and display with automatic synchronization.

Abstract: System and method for identifying tones present in a short segment of digitized music stream, and for reporting simultaneously and quantitatively their respective magnitude and phase in near real time. Also captured are pitch deviations from the nominal tones of a predetermined music scale. The resulting spectral data can be scrolled manually from frame to frame to facilitate detail music evaluation and editing. The apparatus can also operate at real time to display notes being played, or to tone-activate audio-visual music enhancement and display with automatic synchronization.

Abstract: A location system and a location system on a chip (LCoS) and method are described.

Abstract: A system for sensing an absolute two-dimensional position of an object having a two-dimensional target pattern thereon comprises a sensor and a controller. The sensor is for capturing an image of a subset of the target pattern. The controller is for generating a first image vector representing summations of rows of pixel values from the image, and a second image vector representing summations of columns of pixel values from the image. The controller is configured to determine an absolute two-dimensional position of the subset of the target pattern with respect to the origin of the target pattern based on the first image vector, the second image vector and target vectors that represent the target pattern.

Abstract: A location system and a location system on a chip (LCoS) and method are described.

Abstract: A method for non-linearity compensating interferometer position data generated from a measurement signal includes generating a first set of non-linearity parameters based on received digital position values. The method includes sensing whether a low velocity condition exists. A first one of the non-linearity parameters is updated based on an estimated magnitude of the measurement signal if the low velocity condition exists. At least one digital position value is compensated based on the updated non-linearity parameter if the low velocity condition exists.

Abstract: A system for sensing an absolute position in two dimensions includes a target having a two-dimensional target pattern. A sensor captures an image of a first subset of the target pattern. A controller generates a first image vector representing summations of rows of pixel values from the image, and a second image vector representing summations of columns of pixel values from the image. The controller is configured to determine an absolute two-dimensional position of the first subset with respect to an origin of the target pattern based on the first and the second image vectors and a plurality of target vectors that represent the target pattern.

Abstract: A system and method for acquiring position information of a movable apparatus relevant to a specific axis is disclosed. In one embodiment, an interferometer generates first and second beams and various beam-steering members are located to define beam path segments for the two beams, but no beam path segment varies in length in unity with displacements of the movable apparatus along the specific axis. In another or the same embodiment, each beam path segment in which the first beam either impinges or has been reflected from the movable apparatus is symmetrical to a corresponding beam path segment of the second beam. The movable apparatus may be a wafer stage in which the “specific axis” is the exposure axis of a projection lens, but with all optical members which cooperate with the stage being located beyond the ranges of the wafer stage in directions perpendicular to the lithographic exposure axis.

Abstract: A method of digitizing first and second signals in imperfect quadrature for obtaining characteristic parameters of the first signal comprises providing a first signal, the first signal comprising an inphase quasi-sinusoidal analog signal. The method comprises providing a second signal, the second signal comprising a quadrature signal. The method comprises digitizing the first signal at a sampling rate, thereby generating a first plurality of sets of digital signal waveform samples and digitizing the second signal at the sampling rate, thereby generating a second plurality of sets of digital signal waveform samples. The method comprises digitally processing successive first and second sets of digital signal waveform samples to generate continually updated digital characteristic parameters representing a characteristic behavior of the first signal.

Abstract: A system and method for compensating non-linearity of the high-velocity type manifested in heterodyne interferometer position data includes receiving a plurality of groups of digital position values. A plurality of groups of digital phase values from a measurement channel are received. A first group of the digital position values and digital phase values are digitally processed to generate a plurality of block data values. The plurality of block data values are digitally processed to generate at least one quasi-static non-linearity parameter. A second group of the digital position values are compensated based on the at least one quasi-static non-linearity parameter.

Abstract: A system and method for non-linearity compensating interferometer position data includes receiving a plurality of groups of digital position values. A first group of the digital position values are digitally processed to generate a plurality of data values. The plurality of data values are digitally processed to generate at least one quasi-static non-linearity parameter. A second group of the digital position values are compensated based on the at least one non-linearity parameter.

Abstract: A system and method for compensating non-linearity of the high-velocity type manifested in heterodyne interferometer position data includes receiving a plurality of groups of digital position values. A plurality of groups of digital phase values from a measurement channel are received. A first group of the digital position values and digital phase values are digitally processed to generate a plurality of block data values. The plurality of block data values are digitally processed to generate at least one quasi-static non-linearity parameter. A second group of the digital position values are compensated based on the at least one quasi-static non-linearity parameter.

Abstract: A system and method for non-linearity compensating interferometer position data includes receiving a plurality of groups of digital position values. A first group of the digital position values are digitally processed to generate a plurality of data values. The plurality of data values are digitally processed to generate at least one quasi-static non-linearity parameter. A second group of the digital position values are compensated based on the at least one non-linearity parameter.

Abstract: A system and method of digitizing characteristic parameters of a quasi-sinusoidal analog signal of unknown magnitude, frequency and phase-offset, includes digitizing the analog signal at a first sampling rate, thereby generating a plurality of sets of digital signal waveform samples. Successive sets of the digital signal waveform samples are digitally processed to generate continually updated digital characteristic parameters representing a characteristic behavior of the quasi-sinusoidal analog signal.

Abstract: A feed forward apparatus and method discipline a clock signal by a reference signal in digital telecommunication networks. A synthesizer correction term within the feed forward apparatus and method includes a frequency correction term so that when one frequency correction term is selected in place of another frequency correction term the phase of the clock signal remains free from extraneous frequency or phase variations during the transition between frequency correction terms. Alternatively, the synthesizer correction term includes a phase correction term so that phase coherence between the reference signal and the clock signal results.

Abstract: In the present embodiment, digital phase detection of digital telecommunications signals is based on heterodyning. The frequency of two signals are scaled to different nominal values that are separated by a typically small but finite difference. The two frequencies are then mixed to generate a finite beat frequency. In mixing, phase is preserved and the finite beat frequency phase is in one-to-one correspondence with the signal phase. Phase detection is performed indirectly at the lower finite beat frequency with high resolution and greater ease than direct phase detection.

Abstract: A master and a slave digital frequency synthesizer are phase-locked such that the master synthesizer is always selected to minimize the phase hits which occur when switching the master to be a slave and vice versa. The switching rearrangement is done automatically and rapidly in the event of failure of the master frequency synthesizer.

Abstract: A system for characterizing phase modulated signals, e.g., .pi./4 DQPSK signals, includes a time interval analyzer coupled to a system processor for determining a variety of signal characterizing parameters as a function of readings made on a phase modulated signal by the analyzer. The system processor includes a phase/frequency determining section for generating a phase deviation curve and decoding the modulated signal. The system processor further includes a processing section for determining various signal defining parameters including origin offset and I/Q mismatch as a function of the phase deviation.

Abstract: A system for recovering parameters of an underlying clock signal from data modulated signals includes a time digitizer, or time stamping device, for sampling and locating edges of the data modulated signals, thereby selectively providing time stamp readings identifying incoming edges of the data signals. The time stamp readings are used, along with a user-input nominal clock frequency, to determine an array of actual clock cycle stamps, each representing an integral number of actual clock cycles occurring between adjacent time stamps. The array is then used in conjunction with the time stamps to characterize parameters of the underlying clock data. Once the clock parameters are recovered, a wide variety of information, for example, frequency and phase information, including jitter, can be determined with a very modest rate of sampling compared to the high data bandwidth. No phase locked loops are used and no physical clock is recovered.