Abstract: An error corrected wide dynamic range amplifier has a transimpedance amplifier where the input signal node is used as a monitoring point for providing an error correction voltage to a combining circuit that also receives the voltage on the output node of the transimpedance amplifier. The combining circuit subtracts the input signal node voltage from the output signal voltage to produce a resultant voltage substantially free of errors produced by non-ideal characteristics of the transimpedance amplifier. The combining circuit may be implemented using analog or digital circuity. The digital combining circuit may also add digital correction values representative of circuit component errors of the wide dynamic range amplifier. Such a wide dynamic range amplifier is usable in high sensitivity, wide dynamic range optical receivers, such as found in optical time domain reflectometers or other optical measurement instruments.

Abstract: A temperature control system for acoustic wave chemical sensors monitors the frequency output from a reference sensor packaged within a heat conductive case with a test sensor. Since the frequency output fluctuates as a function of temperature, variations in frequency from a nominal value representing a desired steady state temperature for the sensors are detected and used as a control signal for a heating element attached to the heat conductive case.

Abstract: An optical sensor has an electrically adjusted mosaic filter in which each optical filter element of the mosaic filter covers a photosensitive device or region disposed adjacent to the filter. The electrical signals from each photosensitive region or device is amplified, varied and summed to produce an optical sensor output substantially matching a desired spectral response curve as a function of varying the amplified outputs of the photosensitive regions.

Abstract: The present invention provides an ink jet print head having an improved driver design and capable of extended and continuous periods of operation with substantially reduced rectified diffusion-induced printing quality degradation. In preferred ink jet print heads of the present invention, the ink-contacting portion of the surface of the diaphragm of a piezoelectric ceramic/diaphragm drive mechanism is electropolished. By electropolishing only a portion of one surface, the ink-contacting surface, of one ink jet print head component, rectified diffusion is greatly reduced.

Abstract: Reduction of input capacitance in an analog storage array is achieved by reducing the parasitic capacitance presented to an analog signal line. Each column of the analog storage array is coupled to the analog signal line by a separate coupling switch. The switches are activated so that no more than two columns are coupled to the analog signal line at any time, with the next column to be accessed being coupled to the analog signal line prior to access to that column, and the last column being decoupled from the analog signal line after the last cell in the column has been accessed. Further the analog signal line may provide two input ports so that alternate columns of the array are coupled to one port, and the other alternate columns are coupled to the other port so that two adjacent columns are coupled to separate ones of the two ports.

Abstract: Apparatus for generating a phase startable clock signal, comprises an oscillator for providing a continuous sinusoidal input signal, a control signal source for providing a control input signal having a transition between a first state and a second state at a selected time during the signal epoch of the sinusoidal input signal, and a phase splitter, track and holds, multipliers and a summation device for operating on the sinusoidal input signal with the control input signal to produce a sinusoidal output signal commencing with a predetermined phase at a predetermined time relative to the transition.

Abstract: An improvement is provided for current sources of the type having three transistors configured as follows: The bases of the first (Q1) and second (Q2) transistors are tied together. The collector of the first transistor (Q1) is coupled to a first voltage (V.sub.CC,V.sub.EE) via a first resistor (R1). The emitter of the first transistor (Q1) is coupled to a second voltage (V.sub.EE,V.sub.CC) via a second resistor (R2). The collector of the second transistor (Q2) produces the output current (I.sub.OUT). The emitter of the second transistor (Q2) is coupled to the second voltage (V.sub.EE,V.sub.CC) via a third resistor (R3). The base of the third transistor (Q3) is coupled, either directly or indirectly through a fourth transistor (Q4), to the collector of the first transistor (Q1). The collector of the third transistor (Q3) is connected to the first voltage (V.sub.CC,V.sub.EE) and the emitter of that transistor (Q3) is connected to the bases of the first (Q1) and second (Q2) transistors.

Abstract: A transistor amplifier having a main amplifier exhibiting a substantially doubled f.sub.T characteristic and having error cancellation circuitry, wherein the standing current of the error cancellation circuitry is reused in powering the main amplifier. The main amplifier comprises an outer differential pair of transistors and an inner differential pair of transistors, each differential pair having an inverting side and a non-inverting side. The collectors of the transistors of the non-inverting side of the differential pairs are connected, respectively, at a first current summing node. The collectors of the transistors of the inverting side of the differential pairs are connected, respectively, at a second current summing node. The f.sub.

Abstract: A method and apparatus for reducing cross-talk across the width of a pixel, cross-talk along the length of a channel, flicker, and/or image sticking in a display system by providing (a) an electrical circuit (resistor 102, switch 108) for bringing a reference electrode (30') and a row electrode (62') in a channel (20') to the same potential before the gaseous medium in the channel loses an ability to redistribute charge and (b) an electrical circuit (driver 104 and/or driver 26) operable to bring or to clamp one or both of those electrodes to a predetermined electrical potential. Corresponding methods are also provided.

Abstract: A system and method of printing an image on a substrate based on an input of detailed image intensity information for each of discrete pixel areas of the substrate, includes or performs steps of processing the detailed image intensity information into less detailed image intensity information; dithering the less detailed image intensity information to approximate the intensity resolution of the detailed image intensity information; and printing the dithered, less detailed, image intensity information onto the substrate. The system will use less memory space than a comparable system which prints directly from the detailed image intensity information, will minimize patterning effects, and will correct for artifacts which might otherwise be printed.

Abstract: An in-service hum and low frequency distortion measurement technique for in-service cable television channels having a video modulated carrier frequency obtains peak samples of the horizontal sync signal to effectively filter out the vertical interval frequency. The data record formed by the peak samples is filtered and input to a fast Fourier transform to obtain magnitude values for the fundamental and first harmonic frequency components corresponding to a powerline. From these magnitude values hum and low frequency distortion is computed as a percentage relative to the amplitude of the carrier frequency. The same procedure may be used with an input CW signal in an out-of-service measurement for hum only, the difference between the in-service and out-of-service measurements determining the low frequency distortion due to the video signal.

Abstract: A method and the apparatus for employing the method are disclosed whereby an intermediate transfer surface of a layer of sacrificial liquid is applied to a supporting surface and a phase change ink is deposited on the liquid layer. The inked image is then contact transferred to a final receiving substrate.

Abstract: A programmable delay circuit with a simplified structure conserves parts and provides for simplified programmability. In this structure, N delay stages (1-N) each include delay elements (10,26, . . . ,80) that produce delay times that are related as powers of two and are connected by two-input multiplexers (12,22, . . . ,82). The two-input multiplexers select between the input and output of the delay element in their stage, and are collectively controlled by N-bits of delay selection signals that are connected so that less significant bits control multiplexers associated with delay elements producing shorter delays and more significant bits control multiplexers associated with delay elements producing longer delays in a monotonic correspondence. The resulting structure conserves parts and produces an overall delay time that is directly proportional to the binary value used to control the multiplexers.

Abstract: Apparatus for manipulating numerical values stored in a memory comprises a modify device for receiving numerical values from the memory and returning numerical values to the memory. The modify device has at least a first state in which it modifies a numerical value received from the memory in a predetermined fashion before returning the numerical value to the memory and a second state in which it does not modify a numerical value received from the memory in the predetermined fashion before returning the numerical value to the memory. The apparatus also comprises a characterizing device for examining at least some of the numerical values and calculating at least one number that defines a property of the examined numerical values. The characterizing device is connected to the modify device for placing the modify device in the first state or the second state depending on the value of the calculated number.

Abstract: A test signal generator applies a test pattern to a device under test. The output of the device under test is displayed on a video picture monitor. The test signal generator inserts a cursor into the test pattern, the position of the cursor within the test pattern being variable. From the cursor the test signal generator also generates a trigger signal. The trigger signal may be used to trigger the horizontal sweep of a waveform display device to which the output of the device under device is input. By observing the picture monitor an operator may adjust the cursor to a position just prior to an anomaly in the displayed test pattern so that only that portion of the output waveform of the device under test in the vicinity of the cursor is displayed on the waveform display device.

Abstract: A switchable color filter (11) includes three polarizing filters (12, 14, and 16) and two zero to substantially half-wave optical retarders (36 and 38) and is incorporated in a field sequential display system (10) to provide output states of light of three different colors to form an image in full color. Each one of four preferred embodiments (11, 11a, 11b, and 11c) of the switchable color filter provides the output states of three colors. The third and fourth preferred embodiments (11b and 11c) provide a fourth additional output state of, respectively, white light and light of a color which is a combination of two of the other output state colors. The optical retarders comprise nematic liquid crystal cells (100) having fast relaxation times to operate the display system at video rates.

Abstract: An apparatus for directly positioning a hand-held electrical test probe onto leads of a surface mounted integrated circuit, IC, device has a housing with a central bore therethrough for receiving the probing tip of the test probe, which is coupled to compensation circuitry in the probing head. One end of the housing which is normal to the central bore has at least four teeth extending therefrom defining slots for engaging the leads of the IC. The central bore is exposed in the central slot of the housing for exposing the probing tip therein for providing an electrical connection between one of the leads on the IC and the electrical circuitry of the probing head.

Abstract: A semiautomatic lip sync recovery system for time synchronizing the audio and video channels of a television signal uses programmable delay circuits in each channel. An area of the image represented by the video channel is defined within which motion related to sound occurs. Motion vectors are generated for the defined area, and correlated with the levels of the audio channel to determine a time difference between the video and audio channels. The time difference is then used to compute delay control signals for the programmable delay circuits so that the video and audio channels are in time synchronization.

Abstract: A discrete ink level sensing system according to the present invention includes a level sensing probe (130) with at least first and second level sensing pads (178, 180) that is placed in an ink reservoir (28). The level sensing system uses electrical conductivity of the ink to detect when the upper surface level of the ink is lower than the lowest points of the level sensing pads. The upper and lower level sensing pads are electrically connected by a sense resistor (182). A voltage sensor (174) detects across the sense resistor a voltage that depends on the ink conductivity and the position of an upper surface level of the ink with respect to the lowest points of the first and second level pads. The value of the voltage is sent to a CPU (154) that signals a user that a predetermined amount of ink should be added to the reservoir.