Abstract: An ultrasonic imaging system which utilizes two summation channels to provide increased bandwidth employs two demodulation stages in each receive channel. The first demodulator receives digital signals from an analog-to-digital converter and demodulates those signals to baseband, thereby producing an in-phase component and a quadrature component. The in-phase and quadrature components are demodulated by the second demodulator, forming a total of four signals which are filtered and combined to form two sets of complex signals. One set corresponds to the upper or high frequencies and the other set corresponds to the lower frequencies. Each band is treated separately in a subsequent phase rotation. The phase changes reflect those required by the center frequency of each of the subbands. The upper band signals are coherently summed in one summation channel, while the lower band signals are coherently summed in another summation channel.

Abstract: A method and apparatus for remotely calibrating a system having a plurality of N elements, such as a phased array system, is provided. The method includes generating coherent signals, such as a calibration signal and a reference signal having a predetermined spectral relationship between one another. The calibration signal which is applied to each respective one of the plurality of N elements can be orthogonally encoded based on the entries of a predetermined invertible encoding matrix, such as a binary Hadamard matrix, to generate first and second sets of orthogonally encoded signals. The first and second sets of orthogonally encoded signals and the reference signal are transmitted to a remote location. The transmitted first and second sets of orthogonally encoded signals are coherently detected at the remote location.

Abstract: A dual mode ultrasonic imager system operative in both a two dimensional 2-D) mode and doppler mode, includes a plurality of transducers for receiving analog ultrasonic signals and converting them to analog electrical signals, and an analog to digital (A/D) converter system for converting the analog electrical signals to digital signals for further processing. The A/D converter system includes a digital to analog (D/A) converter for converting the digital signals into analog feedback signals, and an analog summer for receiving the analog electrical signals and combining them with the analog feedback signals. An integrator is selectively coupled to receive an output signal from the analog summer and to generate an integrated analog signal. An A/D converter selectively receives, and converts to an equivalent digital signal, one of the integrated analog signal and an output signal of the analog summer.

Abstract: An optical communication system for ultrasound imaging systems employs a light source and photodetector array in the imaging console. The light source and photodetector array are coupled to each other through an optical fiber passing through the probe. Information from the probe is communicated to the console by an optical modulator, situated in the optical path from source to detector. The ultrasound signals are converted into electrical signals by probe electronics, and these electrical signals serve to alter either the phase or amplitude of optical signals passing through the modulator. Since the light source and photodetectors reside in the imaging console, very little power is dissipated in the probe.

Abstract: An ultrasonic imaging system provides dynamic focusing by using dynamic group delay in addition to dynamic phase focus. FIFO memory storage capacity in the beamforming circuit is increased to provide improved resolution of the data samples stored therein. These samples are selected by an address counter in response to both the advance of time and the accumulation of a phase advance clock count. After a Read Start signal, indicating the start of a beam, is supplied to the FIFO memory, the FIFO memory address is advanced, on each read instruction, by the number of address locations corresponding to the period of a pipeline channel. In addition, the address is incremented whenever the accumulated count of a phase advance clock exceeds an amount corresponding to the smallest increment of the data stored in the FIFO memory.

Abstract: An array of weighted summation circuits, N in number, each generate a weighted sum response to the same plurality of input signals, M in number. Each weighted summation circuit includes at least one corresponding capacitive element for determining the weighting of each of the input signals within that weighted summation circuit. At least one corresponding capacitive element is of a programmable type having its capacitance value determined in accordance with the bits of a digital word received at a control word port thereof. The array of weighted summation circuits are preferably constructed in integrated circuit form together with an interstitial memory having respective word storage elements for temporarily storing the digital words applied to the control word ports of nearby capacitive elements in the integrated circuitry.

Abstract: An ultrasonic imaging system beamforming architecture comprises a fixed wideband preprocessor section followed by a reduced number of dynamically adjusted delay channels. The preprocessor includes a transform beamformer with spatial filtering followed by a delay beamformer. Each transform preprocessor provides transformation of the local array space data into beam space. One, or combinations, of these beams may then be selected as input signals to an inverse transform which converts the beam space data back into array space data. This re-establishes the spatial array, but with a reduced directional view, allowing an inverse transform of reduced size to be used for the reconstruction. The result is a decrease in the number of channels required by the remainder of the beamformer.

Abstract: Respective SiC (silicon carbide) photodiode sensors are used to measure flame temperature at each cylinder of an internal combustion engine, and information generated by the SiC photodiode sensors is used to control the fuel injection in a feedback loop to control individual cylinder flame temperature and combustion.

Abstract: An ultrasonic imaging system for displaying color flow images includes a receiver which demodulates ultrasonic echo signals received by a transducer array and dynamically focuses the baseband echo signals. A color flow processor includes a frequency domain adaptive wall filter which automatically adjusts to changes in Doppler-shifted frequency and bandwidth of the wall signal components in the focused baseband echo signals after the echo signals have undergone Fourier transformation into the frequency domain. The mean Doppler-shifted frequency of the resulting filtered baseband echo signals is used to indicate velocity of moving scatterers and to control color in the displayed image.

Abstract: A PASS ultrasonic system includes a separate receive channel for each respective element in an ultrasonic transducer array which imparts a delay to the echo signal produced by each respective element. The delayed echo signals are summed to form a steered, dynamically focused and dynamically windowed receive beam which can be readily interpreted even when the transmit beam does not emanate from the center of the array.

Abstract: Digital synapse input signals which are temporally aligned with each other are converted to analog form for application to a neural net layer. Several digital synapse input signals can be written into digital memory at different times, to be read out in temporal alignment for conversion to analog form for application to a neural net layer. The digital synapse input signals can originate from apparatus for raster-scanning a field or successive fields of video samples, for example, with the neural net layer providing filters for recognizing shapes in a field of the video samples. The neural net layer can be either a pre-programmed type or a learning type, and its axonal outputs may be digitized for use in subsequent digital processing.

Abstract: Neural nets using capacitive structures are adapted for construction in complementary metal-oxide-semiconductor integrated-circuit technology. In each neural net layer synapse input signals are applied to the inverting and non-inverting input terminals of each of a plurality of differential-input non-linear amplifiers by a respective pair of capacitors, which non-linear amplifiers generate respective axon responses. In certain of these neural nets, arrangements are described that make the capacitive structures bilaterally responsive, so that back-propagation calculations can be performed to alter the relative values of capacitors in each pair thereof, which is done during training of certain of the neural nets described.

Abstract: Parallel architectures preprocesses large matrices from sampled coherent time apertures receiving signals from distant sources to produce lower order matrices, derived from pseudo coherent time apertures, which are computationally less burdensome. The large matrices are processed by frequency shifting, low pass filtering with an FIR filter, and executing front-end decimation to create the pseudo coherent time apertures, each corresponding to different subbands of the temporal frequency spectrum. The signals representing the pseudo coherent time apertures are processed using matrix based superresolution spectral estimation algorithms such as the Tufts-Kumaresan (T-K) reduced rank modified covariance algorithm and the Linear Minimum Free Energy algorithms to produce an image of the sources.

Abstract: A plurality of neural circuits are connected in a neural network layer for generating their respective digital axonal responses to the same plurality of synapse input signals. Each neural circuit includes digital circuitry for approximating a sigmoidal response connected after respective circuitry for performing a weighted summation of the synapse input signals to generate a weighted summation result in digital form. In this digital circuitry the absolute value of the digital weighted summation result is first determined. Then, a window comparator determines into which of a plurality of amplitude ranges the absolute value of the weighted summation result falls. A digital intercept value and a digital slope value are selected in accordance with the range into which the absolute value of the weighted summation result falls.

Abstract: A method is disclosed for operating electronic apparatus for generating a weighted summation of digital input signals as manifested in electric signal form, each sample of which digital input signals has a plurality B in number of bits identified by respective ones of consecutive ordinal numbers first through B.sup.th assigned in order of decreasing significance. Successive samples of each of the digital input signals is supplied in a respective stream, such that the respective streams of samples are parallel in time with each other. Each B-bit sample of said digital input signals is recoded into a plurality D in number of binary-coded digits, as manifested in electric signal form and as identified by consecutive ordinal numbers frist through D.sup.th assigned in order of decreasing significance of the respective weighting assigned each of the D binary-coded digits, B and D begin respectively a relatively larger positive integer and a relatively smaller positive integer.

Abstract: Neural nets using capacitive structures are adapted for construction in complementary metal-oxide-semiconductor integrated-circuit technology. Fully differential input amplifiers in each neural net layer apply their push-pull responses to synapse input signals via a pair of input lines. Each push-pull response is applied via a pair of capacitors of complementary capacitance values and an output line to the input of each of a plurality of non-linear output amplifiers in that neural net layer, which generate respective axon responses for that neural net layer. In certain of these neural nets, arrangements are made such that the capacitive structures are bilaterally responsive so that back-propagation calculations can be performed during training periods, to alter the relative values of capacitors in each pair thereof.

Abstract: Plural-bit digital input signals to be subjected to weighted summation in a neural net layer are bit-sliced; and a number N of respective first through N.sup.th weighted summations of the bits of the digital input signals in each bit slice are performed, resulting in a respective set of first through N.sup.th partial weighted summation results. Weighted summations of the partial weighted summation results of similar ordinal number are then performed to generate first through N.sup.th final weighted summation results. Each weighted summation of a bit slice of the digital input signals is performed using a capacitive network that generates partial weighted summation results in the analog regime. In this capacitive network each weight is determined by the difference in the capacitances of a respective pair of capacitive elements.

Abstract: Parallel architectures preprocesses large matrices from sampled coherent time apertures receiving signals from distant sources to produce lower order matrices, derived from pseudo coherent time apertures, which are computationally less burdensome. The large matrices are processed by frequency shifting, low pass filtering with an FIR filter, and executing front-end decimation to create the pseudo coherent time apertures, each corresponding to different subbands of the temporal frequency spectrum. The signals representing the pseudo coherent time apertures are processed using matrix based superresolution spectral estimation algorithms such as the Tufts-Kumaresan (T-K) reduced rank modified covariance algorithm and the Linear Minimum Free Energy algorithms to produce an image of the sources.

Abstract: Parallel architectures preprocesses large matrices from digital phased array systems, receiving signals from distant sources, to produce lower order matrices, called pseudo coherent apertures, which are computationally less burdensome. The large matrices are processed by frequency shifting, low pass filtering with an FIR filter, and executing front-end decimation to create the pseudo coherent apertures, each corresponding to different sectors of the spatial frequency spectrum. The pseudo coherent apertures are processed using matrix based superresolution spectral estimation algorithms such as the Tufts-Kumaresan (T-K) reduced rank modified covariance algorithm and the Linear Minimum Free Energy algorithms produce an image of the sources.

Abstract: Plural-bit digital input signals to be subjected to weighted summation are bit-sliced; and a number N of respective first through N.sup.th weighted summations of the bits of the digital input signals in each bit slice are performed, resulting in a respective set of first through N.sup.th partial weighted summation results. Each weighted summation of a bit slice of the digital input signals is performed using a capacitive network that generates partial weighted summation results in the analog regime; and analog-to-digital conversion circuitry digitizes the partial weighted summation results. Weighted summations of the digitized partial weighted summation results of similar ordinal number are then performed to generate first through N.sup.th final weighted summation results in digital form, which results are respective correlations of the pattern of the digital input signals with the patterns of weights established by the capacitive networks.