Abstract: A microprobe is provided that includes a microsphere optical resonator operatively coupled to a nanoscatterer. The microsphere optical resonator includes a back surface and a front surface opposite the front surface. The front surface is configured to receive a focused laser beam, and the nanoscatterer is positioned adjacent to the back surface.

Abstract: Optical whispering gallery mode (WGM) resonator-based acoustic sensors, imaging systems that make use of the acoustic sensors, and methods of detecting ultrasound waves using the acoustic sensors are disclosed.

Abstract: A microprobe is provided that includes a microsphere optical resonator operatively coupled to a nanoscatterer. The microsphere optical resonator includes a back surface and a front surface opposite the front surface. The front surface is configured to receive a focused laser beam, and the nanoscatterer is positioned adjacent to the back surface.

Abstract: A phase detector includes a decimator to decimate a digitized in-phase signal and a digitized quadrature signal to N times a symbol rate, where N is an integer greater than one. A burst detector to detect bursts in an output of the decimator. A carrier offset block to determine an offset angle based on an output of the burst detector. A rotator to generate a rotated signal by rotating the output of the decimator based on the offset angle determined by the carrier offset block. An equalizer to perform coherent demodulation of the rotated signal.

Abstract: A wireless communication system comprises a sampling module that samples a first portion and a second portion of a channel using a sampling time. A correlator module selectively correlates the first portion and the second portion, generates correlation samples, and calculates an offset based on the correlation samples. A timing module selectively adjusts the sampling time based on the offset.

Abstract: A phase detector includes a decimator to decimate a digitized in-phase signal and a digitized quadrature signal to N times a symbol rate, where N is an integer greater than one. A burst detector to detect bursts in an output of the decimator. A carrier offset block to determine an offset angle based on an output of the burst detector. A rotator to generate a rotated signal by rotating the output of the decimator based on the offset angle determined by the carrier offset block. An equalizer to perform coherent demodulation of the rotated signal.

Abstract: A digital up-sampling converter (DUSC) employs a signal input provided by a digital signal process (DSP) at a first rate feeding a Square Root Raised Cosine (SRRC) filter which provides for table look up of filter coefficients for a multiple symbol span and provides a sampling output at a second rate which is a multiple M of the first rate. A digital to analog converter (DAC) receives the sampling output at the second rate for conversion to an analog signal and a low pass analog filter processes the analog signal for delivery to an RF transmitter.

Abstract: A limiter based analog demodulator includes a power amplifier receiving a base-band signal and a local clock operating at the base-band frequency. A first multiplier receives an output from the power amplifier and the local clock to provide an in phase signal. A quadrature phase shifter receives the local clock and a second multiplier receives the output from the power amplifier and an output from the phase shifter to provide a quadrature signal. Analog filters receive the in phase and quadrature signals and analog to digital converters connected to the analog filters provide digitized in phase and quadrature signals. The phase detector then receives the digitized in phase and quadrature signals.

Abstract: A wireless communication system comprises a sampling module that samples a first portion and a second portion of a channel using a sampling time. A correlator module selectively correlates the first portion and the second portion, generates correlation samples, and calculates an offset based on the correlation samples. A timing module selectively adjusts the sampling time based on the offset.

Abstract: A method of generating a data constellation at a client modem is provided whereby an optimum distance between data constellation data points may be calculated for a predetermined, acceptable error probability. An iterative process may be carried out using proposed data constellations which may be used to provide factors for calculating corrected constellations. Once a constellation is generated to satisfy the required probability of error, the constellation may be re-evaluated using CRC errors and detected noise variance at the client modem. Based upon predetermined levels of noise variance and CRC error, the constellation may be regenerated to operate at either a higher bit rate or a lower bit rate.

Abstract: A Digital Impairment Learning sequence which is designed for providing reliable estimate of digital impairments such as PAD, RBS, and CODEC type in the presence of analog impairments such as IMD, noise and changing line conditions. This estimate is used to derive optimum transmit symbol constellations for a modem connected digitally to a trunk so as to maximize its data transmission rate.