Abstract: A test apparatus for performing line testing of cable and networks. In one embodiment, the test apparatus includes a housing configured to electrically connect with an adapter module while minimizing bends in the electrical connection. The housing and adapter module include mating connectors configured to provide a direct connection between the adapter module and the housing. One embodiment includes a guide feature to ease the insertion of the adapter module into the housing. In another embodiment, the adapter module is configured to form a continuous surface with the housing upon its insertion.

Abstract: A test apparatus for performing line testing of cable and networks. In one embodiment, the test apparatus includes a housing configured to electrically connect with an adapter module while minimizing bends in the electrical connection. The housing and adapter module include mating connectors configured to provide a direct connection between the adapter module and the housing. One embodiment includes a guide feature to ease the insertion of the adapter module into the housing. In another embodiment, the adapter module is configured to form a continuous surface with the housing upon its insertion.

Abstract: A LAN cable tester circuit is disclosed having measurement end circuit components and shorting end circuit components. The measurement end circuit components are conventional and include a multiplexer having a current source and voltage sensing circuitry electrically coupled thereto. The multiplexer also has a plurality of pairs of associated electrical conductors included in the cable under test coupled thereto. The shorting end circuit components include another multiplexer having the opposite ends of the electrical conductors coupled thereto, and further having a differential voltage amplifier and two current output differential amplifiers electrically coupled thereto. The shorting end circuit components provide for an active short that eliminates the effect of the on-resistance attributable to semiconductor integrated circuit multiplexers.

Abstract: An emitter follower amplifier is coupled between the output of a high voltage video amplifier and the cathode of a kinescope for reducing the effective capacitance presented to the video amplifier that is attributable to the kinescope cathode, socket, spark gaps, and related stray capacitances. A secondary undesired capacitance loading of the video amplifier is effectively reduced by regulating the collector-emitter voltages of the emitter follower output transistors at substantially constant values thereby improving parameters such as slew rate and bandwidth of the overall video display system. Nonlinear circuitry in the follower circuit facilitates accurate AKB current sensing and provides simplification of the voltage regulation circuitry. White limiting circuitry is included within the video amplifier for reducing excess peak white drive that results in objectionable smears.

Abstract: A differential transconductance amplifier having a fixed value of differential transconductance provides a video output signal current directly proportional to the transconductance of the amplifier and to a difference between first and second differential video input signals supplies thereto. A pair of buffer amplifiers couples the video input signals to respective inputs of the differential transconductance amplifier via respective diode switches which provides Vber protection for the buffer transistors and provides bus isolation under power down conditions. An output circuit regulates the output voltage of the differential transconductance amplifier at a substantially fixed voltage and converts the output signal current to an output signal voltage. Advantageously, the receiver provides very accurate signal gain control unconditional stability, a wide common mode input voltage range, avoids the need for stand-by power and will not load the input bus under power-down conditions.

Abstract: A complementary push-pull emitter follower amplifier is coupled between the output of a high voltage driver amplifier and the cathode of a kinescope for reducing the effective capacitance presented to the driver amplifier that is attributable to the kinescope cathode, socket, spark gaps and related stray capacitances. A secondary undesired capacitance loading of the amplifier attributable to the collector to base capacitances of the follower amplifier is effectively reduced by regulating the collector emitter voltages of the push-pull follower output transistors at respective substantially constant values thereby improving parameters such as the slew rate and bandwidth of the overall video display system.

Abstract: In a projection television system, a blue phosphor roll-off compensation network is included in the emitter circuit of a common emitter configured transistor comprising the driver amplifier for the blue cathode ray tube. The roll-off compensation network includes a voltage divider connected between the emitter of the common emitter configured transistor and a source of a bias voltage, and a second transistor having its base connected to a point within the voltage divider and its collector-emitter path connected in series with a gain changing resistor between the emitter of the common emitter configured transistor and the source of the variable bias voltage. The voltage divider determines the level of drive current at which the second transistor is rendered conductive and thereby the point at which roll-off compensation is applied. The gain changing resistor determines the amount of compensation.