Abstract: An ink cartridge 10 includes an ink level sensor 38 having a probe supporting structure, such as platform 174, which projects into a collapsible ink container 16 from an ink container support 18. First and second electrical probes 40, 41 are embedded within the structure, with tip portions 188, 190 of the probes 40, 41 being exposed to provide an electrically conductive path through the ink between the probes. Flat closure surface 176, 178 are provided between the exposed portions of the probes against which the container 16 collapses. When the ink container 16 collapses against these surfaces 176, 178, the resistance between the probes increases, is insensitive to ink conductivity, and indicates that volume of ink within the cartridge is low. The platform 174 is supported by tapered necks 180, 182 projecting into the ink container from the ink container support 18.

Abstract: A signal coupling circuit suitable for use in a high-speed signal acquisition probe comprises separate high-frequency and low-frequency signal transmission paths from input to output. The low-frequency path includes a mechanism for variably shifting the DC voltage level at the circuit input to offset quiescent or average voltage levels of an input signal. Values of impedance elements for both the high-frequency and low-frequency transmission paths may be selected to provide predetermined input and output impedances without compromising signal fidelity or limiting signal bandwidth.

Abstract: An oscilloscope is provided with a dual time base system in which the nonlinear startup segment of the main sweep is eliminated before delay time comparison, thereby facilitating accurate differential measurements down to and including the triggering event (zero time). System delays are built in to ensure that the displayed sweep trace also begins at the left edge of the viewing screen, and, moreover, the triggering event may be viewed on both the main and delayed sweeps. The built-in system delays may be programmable to facilitate delay matching of vertical channels or time matching of independent sweep operation.

Abstract: In a line scan graphic recording apparatus, the beam which displays the data on the recording media must be synchronized with the movement of recording media as it is directed normal to the displaying apparatus. The rate at which the recording media moves in its path is determined by the paper drive means. The rate is often non-uniform due to instantanteous velocity variations of the drive means. A drive velocity sensor produces a timing signal which controls the recording time of the input data image, stored digitally in a buffer memory device, by triggering the buffering device at the appropriate time and causing the image data to be transferred to the display for recording on the selected media.

Abstract: An optical connector comprises first and second mating coupling members. The first member has two conductive terminal portions for connection to a driver circuit for a light emitting element, and the second member has a conductive portion which contacts the two terminal portions when the first and second members are coupled together for establishing electrical connection between the terminal portions.

Abstract: The present invention provides a system for applying a fixed level D.C. voltage and a square wave signal sequentially to a voltage divider including a resistor of a known impedance and the device under test. The square wave ranges from a value which is substantially equal to the ground level to a level that is substantially twice the nominal value of the fixed D.C. level, thus the average value of the square wave signal is substantially equal to the nominal value of the fixed level D.C. voltage.With each of these signals applied on at a time to the voltage divider, the voltage across the device under test is applied to a voltage detector via a low pass filter. The output of the low pass filter for each applied voltage signal is the average of the voltage signal which appears across the device under test. The value of these average voltages are stored and then compared.

Abstract: A shadow mask assembly for a cathode-ray tube. The shadow mask assembly includes a taut shadow mask membrane affixed to one edge of a closed frame. The frame is angled inwardly from the edge for increased resistance to buckling. Mounting clips generally aligned with the tube axis are secured to the frame inwardly of the outer edge and project outwardly thereof into engagement with locating holes in the envelope. The clips are deflected inwardly behind the outer edge for disengagement and to permit assembly of the shadow mask into an envelope having an inside dimension close to the outside dimension of the frame.

Abstract: A non-linear amplifier system for a repetitive input signal includes a first amplifier stage for amplifying low level input signals, including noise, in a linear manner and higher level input signals in a non-linear manner. A sampling circuit smooths the output from the first amplifier stage and thereby reduces the amplitude of low level random noise signals. A second amplifier stage receives the output from the sampling circuit and amplifies in a non-linear manner signals corresponding to low level input signals of the first amplifier stage and amplifies in linear manner signals corresponding to higher level input signals of the first amplifier stage. Consequently, low level input signals can be amplified in non-linear manner without introducing substantial errors due to non-linear amplification of low level random noise signals.

Abstract: A circuit for use in association with a sample and hold circuit for preventing a sampled signal voltage from changing with time. The storage capacitor port at the sample and hold circuit is connected through a resistor to a variable voltage divider so that by adjusting the tap of the divider the current through the resistor can be adjusted to match the bias current generated at the capacitor port by the sample and hold circuit. A temperature sensitive device is included in the voltage divider for varying tap voltage and, hence, the matching current with ambient temperature to compensate for corresponding changes in bias current. The voltage divider is connected between the sample and hold output and a common return path to ensure that the voltage at the tap is a function of the sampled voltage and the temperature only.

Abstract: A cable stripper for stripping the protective jacket from the end of a cable. A cable holder secures the cable while a blade, protruding through the guide surface of a blade holder, is urged against the cable and rotated around the cable. The guide surface of the blade holder is continuously biased against the cable surface with the blade protruding to a pre-set depth from the guide surface whereby a consistent depth of cut is achieved.

Abstract: A signal modifying device comprises an elongate section of waveguide and a non-linear circuit element. A lateral through-hole is formed in a wall of the waveguide, and a rod-like conductive member is fitted in the hole and has one end presented towards the opposite wall region of the waveguide. The non-linear circuit element is secured to the rod-like member with one electrode connected in electrically conductive manner to the rod-like member and with a beam-like lead (which is connected to another electrode of the circuit element) extending towards the opposite wall region of the waveguide.

Abstract: An electrical connector is mounted to a panel of conductive material by means of a board of dielectric material secured with one face engaging the panel and having a layer of electrically-conductive material on its other face. The layer of electrically conductive material is in conductive contact with the exterior of the connector. The exterior of the connector can thus be connected to the panel by inserting a conductive screw through the panel so that it contacts the metal layer.

Abstract: A method and an apparatus provide an optical switching system (100) which maintains essentially constant transmissivity at its maximum value and develops independent of viewing angle two system optical transmission states of substantially contaminant-free light. The system includes first and second light gates (102 and 104) of which each has associated therewith contaminant light intensity patterns (48 and 66) with points of local maxima (54, 56, 58, 60, 68, and 70) and local minima (62 and 72) in two system optical transmission states. Quarter-wave plates (134 and 136) are positioned between the light gates to develop circular polarization of light propagating between them. The presence of circularly polarized light maintains the system transmissivity at its maximum value while the relative orientation of the light gates is changed to align their contaminant light intensity patterns to block the transmission of contaminant light, and thereby improve the viewing angle performance.

Abstract: An ink jet printer having an ink jet head unit including a head and a three way valve mounted on a bracket. The bracket is removabley mounted to the printer and allows the unit to be replaced in the field. The valve of the new unit is positioned to close off flow to the head while opening flow from the ink source outlet to a disposal outlet. Upon connection of the new unit to the system, a quantity of ink is flushed through the valve to remove impurities introduced during the connection process. The valve is then adjusted to connect flow of ink to the head while closing off the disposal outlet and thereby avoid contamination of the new head.

Abstract: A delay compensation method and apparatus for digital display systems includes a differential clock generator which controls the timing of progenitor digital signals in separate signal-processing channels so that reconstructed horizontal and vertical analog signals arrive at a display device in a precise time match. Thus, timing errors may be adjusted out while the signals are still in digital form to provide an undistorted display.

Abstract: An apparatus for generating a video signal suitable to cause a representation of repetitive waveform to be displayed on a raster scan display device comprises a differential amplifier which forms an output signal representing a clipped version of the instantaneous difference between the voltage of the waveform and a voltage representing the position of the raster scan line then being executed. An absolute value circuit receives the output signal of the differential amplifier and generates an output signal representing the absolute value of the output signal of the differential amplifier with respect to a reference level. The absolute value signal is inverted and level shifted, and is amplified so that its excursions are of predetermined magnitude.

Abstract: This invention includes a method and apparatus for causing ink to be ejected from the ink nozzles for a second selected time period if the printer has not functioned for a first selected time period independent of whether power is or is not applied to the printer during those periods. The first time period is selected to minimize the possibility of ink clogging the ink nozzles and the second time period is selected to dislodge any thickened ink which may have developed in the ink nozzle during the first time period. The first time period for most ink compositions and nozzle sizes will be considerably longer than the second time period.

Abstract: An input apparatus for a multi-channel device, such as a logic analyzer, is disclosed, the input apparatus providing the multi-channel device with a programmable set-up and hold feature. The multi-channel device acquires a logic signal from a product under test, the logic signal having associated therewith an actual set-up and hold time with respect to an external clock signal. The actual set-up and hold times are entered into the multi-channel device via a keyboard and a display. The device has stored therein a desired set-up and hold time required by the logic signal relative to the external clock signal. In accordance with the actual and the desired set-up and hold times, the multi-channel device changes the relative orientation of the acquired logic signal with respect to the external clock signal, along the time axis until the set-up and hold times of the acquired logic signal are changed from the actual value to the desired value.

Abstract: A signal-envelope display system for a digital oscilloscope includes a memory for storing minimum and maximum signal values in adjacent storage locations, an address counter for sequentially addressing the memory, and a control circuit for selectively inverting the least significant bit of the address count signal. The values retrieved from the memory are converted to analog values and a low-pass filter connects the analog values to provide a signal envelope display.

Abstract: A programmable trigger coupling circuit and trigger circuit for selecting DC and AC coupling modes in addition to a few other coupling modes without using a DC blocking capacitor in series with the signal path. A short high frequency signal path, low pass filter network and a subtraction circuit are used for obtaining the basic trigger coupling modes. Additional circuits may be used for expanded coupling modes and functions.