Abstract: Systems and methods that measure the delay (latency) through a digital processor or circuit. A waveform generator outputs a primary (chirp) signal to the digital circuit, along with an auxiliary pulse signal to a delay circuit. The auxiliary signal corresponds to a sample of the primary signal that is input to and output from the digital circuit. A clock circuit provides input and output clock signals to the digital circuit and delay circuit. Clocked outputs of the digital circuit and delay circuit are input to an analyzer. The time delay between the auxiliary signals and delayed auxiliary signals are measured by a time measurement circuit. The analyzer processes the outputs of the processor and delay circuit and the time delay (reference time) using an analysis routine to determine the latency of the digital circuit.

Abstract: A system for extracting a gas and a liquid from a well broadly includes tubing strings that collect well liquid and a gas lift system that removes the collected liquid. A standing valve connects the strings and permits liquid to enter the strings from the subsurface formation. The gas lift system includes a compressor that uses pressurized gas to remove the collected liquid and discharge the liquid into a separator. The system permits liquid to be collected and removed while simultaneously producing gas from the well casing. The system includes an accumulator that stores compressed gas for removing the collected liquid.

Abstract: A system for extracting a gas and a liquid from a well broadly includes tubing strings that collect well liquid and a gas lift system that removes the collected liquid. A standing valve connects the strings and permits liquid to enter the strings from the subsurface formation. The gas lift system includes a compressor that uses pressurized gas to remove the collected liquid and discharge the liquid into a separator. The system permits liquid to be collected and removed while simultaneously producing gas from the well casing. The system includes an accumulator that stores compressed gas for removing the collected liquid.

Abstract: A system and method for maintaining privacy in transmission of a high bandwidth analog signal. A preferred system and method breaks an input signal into bands and then uses Walsh codes to overlay many signals on top of each other with a set of phase modulators to establish scrambling of the input signal. The scrambled signal is then transmitted. The received scrambled signal has the phase modulation removed and an inverse Walsh transform recovers the original bands. The recovered bands are added together to recover the original signal. The system and method use techniques that establish synchronization and phase coherency complete the process.

Abstract: A system for changing the sample rate of a digital signal precisely such that frequency coherence is maintained. The system uses coupled direct digital synthesizers to establish the phase of a resampled clock compared to the original clock. The system implements precision resampling that changes the sample rate of a sampled data signal, while maintaining the frequency coherence of the sampled signal. A precision phase calculation for the relation between an input clock and an output clock enables the precision resampling.

Abstract: Systems and methods that measure the delay (latency) through a digital processor or circuit. A waveform generator outputs a primary (chirp) signal to the digital circuit, along with an auxiliary pulse signal to a delay circuit. The auxiliary signal corresponds to a sample of the primary signal that is input to and output from the digital circuit. A clock circuit provides input and output clock signals to the digital circuit and delay circuit. Clocked outputs of the digital circuit and delay circuit are input to an analyzer. The time delay between the auxiliary signals and delayed auxiliary signals are measured by a time measurement circuit. The analyzer processes the outputs of the processor and delay circuit and the time delay (reference time) using an analysis routine to determine the latency of the digital circuit.

Abstract: A frequency and phase locked loop having improved performance. The loop measures both frequency and phase of a modulated signal to supply a carrier for demodulation of a quadrature amplitude modulated signal (QAM) signal and for many other applications. The addition of the frequency measurement and the use of finite impulse response filters instead of infinite impulse response filters of a phase locked loop permit the loop to lock to the carrier much more rapidly and with a larger offset.

Abstract: A high definition digital image projection system that uses modulated lasers to project high resolution images at frame rates that are used in the movie industry. An exemplary system employs digital-to-analog converters that convert digital signals derived from an image memory that correspond to predetermined colors that make up an image into analog signals for the respective color. A plurality of lasers 13a, have their light intensity outputs respectively modulated by the outputs of the digital-to-analog converters. A plurality of optical devices such as color sensitive half-silvered mirrors or sets of prisms having color-sensitive coatings on their respective faces, are used to produce a coaxial set of laser beams. First and second rotating mirrors are used to reflect the coaxial set of laser beams and generate an image for viewing. A mirror rotation synchronization circuit synchronizes rotation of the first and second rotating mirrors.

Abstract: A method and apparatus that provide for automatic speech transcription that may be used transcribe structured reports. The method and apparatus provide for speaker dependent, continuous speech recognition using a limited vocabulary. Transcription is based on recognition of a vocabulary of sounds followed by a translation to text. The translation to text matches spoken sounds to sounds contained in similar recorded text sequences. Training involves speaking a set of words with the desired sounds imbedded therein. The method and apparatus recognize phrases, not words, and works well in a radiology or similar application because of the use of a very limited vocabulary to generate reports.

Abstract: A system and method for maintaining privacy in transmission of a high bandwidth analog signal. A preferred system and method breaks an input signal into bands and then uses Walsh codes to overlay many signals on top of each other with a set of phase modulators to establish scrambling of the input signal. The scrambled signal is then transmitted. The received scrambled signal has the phase modulation removed and an inverse Walsh transform recovers the original bands. The recovered bands are added together to recover the original signal. The system and method use techniques that establish synchronization and phase coherency complete the process.

Abstract: A system and method that introduces intentional errors into a compression scheme for images. The intentionally introduced errors along with error correction processing enable improved low entropy encoding of the images. The errors transmitted over a communication channel are reduced by adding an error correction code to the transmitted data. In an exemplary system and method, an image is blocked to create a plurality of pixel blocks. The blocked image is transform coded and quantized to quantize transform coefficients. The image is low entropy coded. The image is error correction coded to improve communication through a communication channel that introduces errors. The entropy coded coefficients are truncated to introduce intentional errors into the image that is communicated over a communication channel. Upon reception, blocks of the received image are expanded to produce entropy coded coefficients, which are error correction decoded.

Abstract: A high resolution, high speed digital camera that produces a high resolution image representative of an image scene viewed by the camera. The digital camera comprises an input lens system and an iris that couple light from the image scene into the camera. A first imager generates a sequence of high resolution, low speed digital frames of the image scene. A second imager generates a sequence of low resolution, high speed digital frames of the image scene.

Abstract: Apparatus and methods for compressing an audio signal. An analog to digital converter is used to digitize the audio signal. A linear predictor processes the digitized audio signal to attenuate coherent noise and produce a residual output signal that is representative of the audio signal. An improved synchronized overlap add processor employs a one bit correlator and a smoothly-shaped window compresses the digitized audio signal. The synchronized-overlap-add processing may be used with voice or audio processing systems to change the time scale of the voice (audio) signal without changing the pitch of the processed signal. The synchronized-overlap-add processing may also be used to reduce noise in the processed signal. The present synchronized-overlap-add processing technique makes the computations required very quick, improving the utility of the processing.

Abstract: A combining technique for coherently combining signals transmitted from a moving satellite that are received by separate antennas. The combining technique corrects for differential delays that are large enough to cause misalignments in the symbols of the communication signal as well as the phase of the signal. Further the combining technique tracks changes in the differential delay, keeping the phase and the symbols properly aligned for combining.

Abstract: An image processing apparatus and method that completely removes blocking artifacts from a compressed and restored digitized image. A compressed image is formed by windowing pixel data with a smooth window (discrete cosine transform) and then folding (wrapping) the windowed pixel data to form a modified image that is the same size as the original image. The wrapped and folded image is thereafter processed using a conventional discrete cosine transform and coder to produce the compressed image. To restore the original image, an inverse discrete cosine transform is used to process the compressed image, then the pixel data is unfolded (unwrapped), windowed, and combined to form the restored image. The present invention may be used to process data, such as voice signals, and images other than radiological images. The transform used in the present invention may also be a Fourier transform, for example.

Abstract: A filtering technique that results in improved performance of interpolating filters. The improved filter and technique replicates samples of the digital input signal instead of inserting zeroes before smoothing to eliminate undesired images of the sampled input signal. The filter includes a digital equivalent of a sample and hold for sampling the digital input signal at the input sample rate and for replicating the sampled digital input signal a predetermined number of times to increase the sample rate by an integer multiple and produce replicated samples of the input signal. A smoothing filter is coupled to the digital sample and hold for smoothing the replicated samples. The smoothing filter has a shape having a high frequency enhancement followed by a sharp cutoff that compensates for the replicated samples of the input signal. Interpolated digital output signals are provided therefrom that are at a sample rate higher than the input sample rate.

Abstract: An ultrasound imaging system for generating high resolution, three-dimensional images of the body for medical imaging. The system includes a housing with a rotatable disk at one end having an aperture therein and a plurality of pairs of ultrasonic transducers disposed around the periphery thereof. A flexible member encloses the housing and a fluid filled cavity disposed in the housing in which the transducers are immersed. An ultrasonic transmitter is coupled to the aperture for transmitting ultrasonic energy by way of the aperture, fluid filled cavity and flexible member. A receiver is coupled to the ultrasonic transducers and a processor is coupled to the receiver for sequentially processing reflected ultrasonic energy received by the pairs of ultrasonic transducers to produce a high resolution, three-dimensional image of the body. The system forms a synthetic aperture using the moving ultrasonic transducers.

Abstract: Apparatus that provides working storage for large image and data processing systems. The apparatus comprises a computer bus, a high speed backplane bus, a local area network, a central processing unit coupled to the computer bus, an Ethernet local area network interface coupled between the computer bus and the local area network, a plurality of bidirectional input/output interface cards coupled to the computer bus and the backplane bus, and a plurality of disk modules coupled to the computer bus and the high speed backplane bus. Each interface card comprises a plurality of bidirectional input/output ports coupled to a plurality of user workstations, a fiber optic interface, and a FIFO buffer. Each disk module comprises a plurality of storage units, one of which provides for storage of parity bits and the remainder of which provides for storage of data, and a distribution card coupled to the plurality of storage units.

Abstract: A compressing a voice signal by the steps of (a) digitizing an input signal that includes a voice signal, the input signal including a coherent noise component; and (b) compressing the digitized voice signal with a synchronized overlap add processor (20). So as to prevent the synchronized overlap add processor from locking to the coherent noise component, the step of compressing includes an initial step of applying the digitized input signal to a linear predictor (16), the linear predictor having time constants selected for attenuating the coherent noise component of the input signal. The residual signal output of the linear predictor includes the voice signal, and an uncorrelated noise component if one is present in the input signal. The operation of the synchronized overlap add processor also functions to attenuate the incoherent noise component.

Abstract: A signal detector discriminates between signals manifesting noise and signals manifesting information, both of which appear at an input. A analog-to-digital converter circuit samples the signals and a Fourier filter determines, for each signal sample, energy content of each of a plurality of frequency cells in the sample. A processor then determines the mean energy content and the average variance of energy content in all frequency cells in the signal sample. The mean energy content and average variance of energy content of the signal sample are then compared, and if the comparison indicates an approximate equality, the sample is declared to be noise. The processor further determines a centroid center frequency for the frequency cells in the sample which indicates, if it is on-center, that the sample is likely to be noise. The processor further determines the bandwidth of the Fourier components of the input signal, to determine if it is indicative of noise.