Abstract: In general, a method includes comparing a first input signal with a second input signal to produce an output signal. The first input signal corresponds to an amount of light detected by a sensor, and the second input signal corresponds to an aggregated value of the output signal. The method may also include aggregating the output signal in a digital accumulator and converting a digital signal from an output of the digital accumulator to an analog signal.

Abstract: In general, a method includes comparing a first input signal with a second input signal to produce an output signal. The first input signal corresponds to an amount of light detected by a sensor, and the second input signal corresponds to an aggregated value of the output signal. The method may also include aggregating the output signal in a digital accumulator and converting a digital signal from an output of the digital accumulator to an analog signal.

Abstract: In an image sensor, the current through the in-pixel readout transistor is sensed by a circuit that is external to the pixel, and according to the measured current value a feedback current is supplied to charge the read-line parasitic capacitance. The feedback current is supplied by a circuit that also is external to the pixel area. The amplifier structure is reconfigurable so that it can be used both to read out and to reset the pixel.

Abstract: A method of embedding useful data in a digital music file in a way that maintains compatibility with existing digital music formats and players and has no effect on the size of the digital music file or sound quality. A digital music file is analyzed to determine a list of start and end locations of at least n consecutive zeros, defining a list of record locations, where n is an integer greater than two. The file store locations are written in initial record locations of the list of record locations and the data and a start key is written remaining record locations of the list of record locations. A process of retrieving the embedded data is also disclosed.

Abstract: In general, a method includes comparing a first input signal with a second input signal to produce an output signal. The first input signal corresponds to an amount of light detected by a sensor, and the second input signal corresponds to an aggregated value of the output signal. The method may also include aggregating the output signal in a digital accumulator and converting a digital signal from an output of the digital accumulator to an analog signal.

Abstract: A system and method for image sensing and processing using the Arithmetic Fourier Transform (AFT). An image sensing array has sensors located based on a set of Farey fractions, each multiplied by a unit block size of the array. Similar sampling can be achieved by interpolating the pixel values of a conventional, uniformly spaced array of sensors. The AFT can be determined extremely efficiently by computing weighted sums of the representative pixel values. Corresponding Discrete Cosine Transform (DCT) coefficients can then be computed by scaling the AFT coefficients. As a result, the number of multiplication operations required to compute the DCT is dramatically reduced.

Abstract: In an array of imaging elements, a pixel level analog-to-digital-converter design splits the quantizer into an input transistor at the pixel location and a quantizer body for each row. The feedback digital-to-analog converter is also split into two components, one at the pixel location and one provided either for each row or for the entire array.

Abstract: Data are embedded in an audio signal for watermarking, steganography, or other purposes. The audio signal is divided into time frames. In each time frame, the relative phases of one or more frequency bands are shifted to represent the data to be embedded. In one embodiment, two frequency bands are selected according to a pseudo-random sequence, and their relative phase is shifted. In another embodiment, the phases of one or more overtones relative to the fundamental tone are quantized.

Abstract: In a high-pass (mirrored) integrator structure that employs chopper modulation, the input and output of the mirrored integrator are connected to the input and output ports of the operational amplifier, bypassing the chopper stabilization modulators. The mirrored integrator can be used in sigma-delta analog-to-digital converters.

Abstract: An image-sensing element has an array of photodiodes or other photodetecting elements and performs sigma-delta analog-to-digital conversion on the outputs of the photodetecting elements. The sigma-delta analog-to-digital converters have components divided between pixel-level and row-level structures, with each row-level structure connected to its pixel-level structures to define a multiplexed-input-separated sigma-delta analog-to-digital converter. The converter can include an integrator or can rely on an integration effect of the photodetecting element. The feedback required for sigma-delta analog-to-digital conversion can involve digital-to-analog converters located at each row-level structure or at each pixel-level structure.

Abstract: An autonomous sensor system is provided for powering sensors using thermoelectric modules driven by thermal energy. The system includes solid-state thermoelectric (TE) modules for the conversion of thermal energy to electrical energy. The TE modules are composed of p-type and n-type semiconductors that are interdigitated so that the p-type and n-type elements form thermocouples. The TE modules derive electrical power from thermal energy available in the immediate environment. The system also includes sensors that are powered by the TE module, wherein a corresponding free space signal is generated.

Abstract: A delta to sigma modulator or analog to digital converter uses a mirrored integrator. (The mirrored integrator has a frequency response function that is a mirror image—about half the Nyquist frequency—of a conventional integrator thus giving infinite gain at the Nyquist frequency.) The input signal is modulated with a chopper signal alternating between +1 and −1. The chopped input signal is added to a feedback signal and applied to the mirrored integrator. It is then quantized and high-pass filtered. The frequency of the input signal is thus shifted from the low-frequency spectrum.

Abstract: The present invention provides an apparatus and method for in-situ testing of transducers, and more particularly to the testing of piezoelectric transducers including piezoelectric accelerometers. Circuits, measurement techniques, and interpretative algorithms to enable in-situ testing of piezoelectric accelerometers are described. Accelerometers that employ a piezoelectric material to convert mechanical strains into electronic signals are reciprocal electromechanical transducers. In such transducers the electrical output impedance of the sensor is dependent upon the electrical and mechanical parameters of the sensor. The procedure described in this disclosure includes methods of measuring the transducer electrical output impedance as a function of frequency and the extraction of the electrical and mechanical transducer parameters from the measured data. The measured values of the transducer parameters may be interpreted to provide an indication of the operational status of the transducer.

Abstract: A method for interleaving data in packet based communications includes interleaving elements of data in a source sequence to form an interleaved sequence and transmitting the interleaved sequence of the elements of the data. Adjacent elements of data in the interleaved sequence originally were separated by a first number of elements of data in the source sequence. Additionally, originally adjacent elements of data in the source sequence are separated by at least a second number of elements of data in the interleaved sequence.

Abstract: The present invention provides an apparatus and method for in-situ testing of transducers, and more particularly to the testing of piezoelectric transducers including piezoelectric accelerometers. Circuits, measurement techniques, and interpretative algorithms to enable in-situ testing of piezoelectric accelerometers are described. Accelerometers that employ a piezoelectric material to convert mechanical strains into electronic signals are reciprocal electromechanical transducers. In such transducers the electrical output impedance of the sensor is dependent upon the electrical and mechanical parameters of the sensor. The procedure described in this disclosure includes methods of measuring the transducer electrical output impedance as a function of frequency and the extraction of the electrical and mechanical transducer parameters from the measured data. The measured values of the transducer parameters may be interpreted to provide an indication of the operational status of the transducer.

Abstract: An autonomous sensor system is provided for powering sensors using thermoelectric modules driven by thermal energy. The system includes solid-state thermoelectric (TE) modules for the conversion of thermal energy to electrical energy. The TE modules are composed of p-type and n-type semiconductors that are interdigitated so that the p-type and n-type elements form thermocouples. The TE modules derive electrical power from thermal energy available in the immediate environment. The system also includes sensors that are powered by the TE module, wherein a corresponding free space signal is generated.