Abstract: A photocurrent detector circuit includes a photodiode coupled to an input terminal of a first operational amplifier. A first resistor has a first end coupled to the photodiode and a second end coupled to an output terminal of the first operational amplifier. A first diode has a first end coupled to the photodiode. A second resistor has a first end coupled to a second end of the first diode. A low gain bias network is coupled between a second end of the second resistor and the output terminal of the first operational amplifier. A second diode has a first end coupled to the photodiode. A clamp bias network is coupled between a second end of the second diode and the output terminal of the first operational amplifier. Preferably, the photodiode and the first and second diodes include silicon carbide. The detector may further include second and third operational amplifiers coupled to the output terminal of the first operational amplifier.

Abstract: A correlator for identifying global positioning satellites includes an antenna at a central location for receiving signature signals from a plurality of the satellites. Each received signal is converted from analog to digital form. A filter is employed to correlate each digital signal with a respective, unique code sequence. Each filtered digital signal is supplied to a circuit which produces an indication that identifies each satellite from the filtered digital signal supplied to the circuit.

Abstract: Intensity of optical emission from a combustion flame within a gas turbine combustor is monitored through an optical window in the combustor wall by a primary detector. Because the window is susceptible to becoming coated with deposits during combustor operation, compensation for presence of a coating is achieved by directing illumination from an optical signal source, such as a silicon carbide light-emitting diode, into the window for internal reflection at an optical interface defined by the combustion side surface. A compensation detector, such as a silicon carbide photodiode, detects intensity of the internally reflected illumination as an indicator of the window coating thickness. The compensation detector is located at a non-combustion side of the window, along with a reference detector that responds to intensity of optical signal source illumination reflected from the non-combustion side surface of the window.

Abstract: For protecting the gate insulating layer of an insulated gate field-effect transistor from electrostatic charges, the main terminals of a depletion mode (normally conducting) field-effect transistor, serving as a protection transistor, are connected between the gate and source terminals of the transistor to be protected, thus providing a shunt path for electrostatic charges when the protection transistor is not biased out of conduction. For normal operation, the protection transistor is biased out of conduction by applying to its gate terminal the voltage drop across a biasing resistor in series with the source terminal of the insulated gate field-effect transistor. This protection arrangement is particularly advantageous for silicon carbide field-effect transistors which are not readily suited to application of conventional (i.e. silicon transistor) gate insulating layer protection techniques.

Abstract: An optical detection system includes an array of photodetectors, each of which is positioned for receiving light and converting the light into an electrical signal. A plurality of high pass filters is positioned with each one of the high pass filters electrically coupled to a respective photodetector for passing a portion of a respective electrical signal having frequency components at least as high as the high pass filter cutoff frequency. In one embodiment, each one of the filters comprises a capacitance coupled to the photodetector and a depletion mode FET with shorted gate-to-source terminals coupled between the photodetector and a bias voltage source.

Abstract: A depletion mode MOSFET and resistor are fabricated as a silicon carbide (SiC) integrated circuit (IC). The SiC IC includes a first SiC layer doped to a first conductivity type and a second SiC layer overlaid on the first SiC layer and doped to a second conductivity type. The second SiC layer includes at least four more heavily doped regions of the second conductivity type, with two of such regions comprising MOSFET source and drain electrodes and two other of such regions comprising resistor electrodes. The second SiC layer includes an isolation trench between the MOSFET electrodes and the resistor electrodes. At least two electrically conductive contacts are provided as MOSFET electrode contacts, each being positioned over at least a portion of a respective MOSFET electrode and two other electrically conductive contacts are provided as resistor electrode contacts, each being positioned over at least a portion of a respective resistor electrode.

Abstract: An output circuit for use with an array of high dynamic range analog sensor produces a digital output signal from the array prior to multiplexing, so as to avoid analog multiplexing noise. The analog signals are converted to digital form using a simple, parallel analog-to-digital conversion process at the outputs of low noise array amplifiers. By latching the converted digital output signals into shift registers, the analog multiplex function is obviated and the full dynamic range capability of the detector-amplifier combination is made available.

Abstract: An output circuit for use with an array of analog energy detectors includes a system for digital companding which is capable of providing output signals with an enhanced dynamic range. A digital compressor is provided for converting the output signals of the analog detectors into compressed digital values. Accumulators are provided for holding the output signals of the digital compressor. An expander is provided to expand the digital output signals held in the accumulators to determine the energy patterns impinging on the array of analog detectors.

Abstract: An interferometer Fourier transform spectrometer, having increased speed, is capable of performing a Fourier transform in parallel, in analog form, using a weighted matrix. The spectrometer includes a linear detector array responsive to an interferogram. The detector array is coupled to a plurality of integrating sampling amplifiers. Each column of a group of columns of the matrix is coupled in parallel to a respective integrating sampling amplifier, and the output signals from each row of a group of rows form an output signal array.

Abstract: In an array of charge injection device (CID) detectors, integer amplification is incorporated into each respective detector of the array. The amplifier for each CID detector in the array performs multiple nondestructive readouts. This provides a gain of N amplification of the signal charge in that detector wherein the signal charge is accurately replicated in a separate charge storage well defined by a magnitude capacitor coupled to the detector. Thus, at the end of the readout process, this separate well contains charge equal to N times the signal charge, N being the number of nondestructive readout cycles in the readout process.

Abstract: An analog line store comprises a bank of storage capacitors n in number, an n:1 read multiplexer for sequentially sampling from the n storage capacitors as part of a read-then-write operation, a 1:n write multiplexer for sequentially sampling to the n storage capacitors as a further part of the read-then-write operation, and a scanning register for generating control signals for the write multiplexer and the read multiplexer. The storage capacitors have similar capacitances that are substantially invariant with change in stored charge. Such an analog line store is integrated together with a solid-state imager array to provide for the cancellation of fixed pattern noise from the imager video output signal.

Abstract: A low capacitance radiation detector comprises a monocrystalline silicon substrate heavily doped to N type conductivity with a more lightly doped N type conductivity epitaxial layer formed on the substrate. A plurality of heavily doped N type upper surface layer segments are formed in the epitaxial layer. A patterned region of the epitaxial layer, heavily doped to P type conductivity and in the shape of parallel stripes joined at each end by a respective stripe perpendicular to the parallel stripes, is formed in the epitaxial layer and situated between adjacent ones of the upper surface layer segments, with each stripe extending into the epitaxial layer deeper than, and separated from, the upper surface layer segments so as to form a minority charge carrier-collecting PN junction with the epitaxial layer.

Abstract: The linearity and dynamic range of a photodetector system is enhanced by providing real time cancellation of condition-dependent quiescent output signals from the photosensitive devices by provision of a condition-dependent output signal monitoring device which drives the input section of a current mirror having output sections connected to the active photosensitive devices to zero out the condition-dependent quiescent output signals of those photosensitive devices during system operation. Multiple output sections may be run from a single input section of the current mirror.

Abstract: Respective processors for pairs of photodetecting elements are included in an imager used for sensing hologram fringe patterns in an optical interferometer. These processors remove the direct-current pedestal from in-phase and quadrature-phase field images, then perform partial correlations of the resulting field images on a pixel-by-pixel basis, and then sum the partial correlations to complete the image correlation process and to provide imager output signal or the basis therefor. This localized processing greatly reduces the number of samples that have to be brought out of the imager each frame when the imager is used in an optical interferometer to detect phase modulation in an optical signal, allowing for increased frame rates in accordance with a further aspect of the invention. Image correlation is done according to a novel algorithm that avoids actually having to multiply together correspondingly located pixels in each pair of successive fields forming a successive non-overlapping frame.

Abstract: An array of charge storage devices each including a pair of closely coupled conductor-insulator-semiconductor capacitors or cells, one a row line connected cell and the other a column line connected cell, is provided on a common semiconductor substrate. The charge stored in a row of devices is read out by transferring charge from a column cell to a row cell and then back again to the column cell by reducing and then increasing the absolute value of the voltage on column cell of each of the devices of the row in sequence. The resultant change in voltage produced on the row line is sensed and an electrical signal is obtained representing the charge stored at each of the devices of the row.

Abstract: A charge injection imaging device comprises low bandwidth, low noise performance column amplifiers serially connected to respective charge coupled device storage lines. Image and/or noise defining electronic information signals are retrieved from the charge injection imaging device by way of the amplifiers and storage lines in a manner which provides image defining electronic information signals from which the noise defining electronic information signal portions have been automatically subtracted for each succeeding photosensitive element of the device. The subtracted noise portions include both KTC noise and fixed pattern noise which are normally inherently associated with the image defining electronic information signals retrieved from the charge injection imaging device.

Abstract: A charge injection device image sensor, having increased sensitivity and dynamic range, utilizes a two-dimensional array of cells having m rows each with n cells arranged in n columns. A video preamplifier is connected to each associated column to amplify, in parallel, video signals from that one column, responsive to all of the n cells along a particular one of the m rows being simultaneously enabled. The rows are scanned in mutually-exclusive fashion. Each of the n amplified column signals is separately stored. The stored column signals are sequentially readout to provide the sensor video output signal.

Abstract: A charge injection device image sensor, having increased sensitivity and dynamic range, uses a two dimensional array of cells having m rows each with n cells arranged in n columns. Peripheral electronics first reset all cells along each of the columns, then sequentially scan each column to generate a row voltage signal before advancing to the next sequential row and repetitively scanning across the cells until all array cells have been raster scanned. A voltage preamplifier is connected to each associated row to amplify the video signal only when the cells along that row are being scanned, and reduces the total capacitance of the row-selection electronics.

Abstract: A high-sensitivity photometer/radiometer uses a single-pixel charge-injection-device (CID) light-sensitive sensor, and associated circuitry for: non-destructively reading-out the sensor charge level; for summing signals proportional to the charge level signal; and for then displaying the level. With cooling of the CID sensor, the sensitivity of the photometer can be sufficient to read incident flux levels on the order of several photons per second.

Abstract: An array of charge storage devices each including a pair of closely coupled conductor-insulator-semiconductor cells, one a row line connected cell and the other a column line connected cell, is provided on a common semiconductor substrate. Readout of the charges stored in a row of devices is accomplished by transferring the charge in each of the devices of the selected row of devices in one direction between the row line connected cell and the column line connected cells of a device in sequence and sensing the resultant current flow in the row line of the selected row of devices.