Abstract: An active load arrangement is used to provide proper output load to an object TO under test. The arrangement Z comprises a voltage_controlled transistor MOSFET having a source S, a gate G and a drain D. The drain D is associated with the gate G and connected to an arrangement input I2 associated with an output O1 of the object under test. The source S is connected to an arrangement output O2 associated with an input I1 of the object under test. A feedback arrangement is connected to the source S and the gate G. The feedback arrangement changes phase and amplitude of the gate-to-source voltage by varying frequency in order to obtain low impedance at low frequencies and high impedance at high frequencies.

Abstract: An active load arrangement is used to provide proper output load to an object TO under test. The arrangement Z comprises a voltage_controlled transistor MOSFET having a source S, a gate G and a drain D. The drain D is associated with the gate G and connected to an arrangement input I2 associated with an output O1 of the object under test. The source S is connected to an arrangement output O2 associated with an input I1 of the object under test. A feedback arrangement is connected to the source S and the gate G. The feedback arrangement changes phase and amplitude of the gate-to-source voltage by varying frequency in order to obtain low impedance at low frequencies and high impedance at high frequencies.

Abstract: A phase detector arrangement for use in a phase locked loop circuit recovers clock and data pulses from a data stream comprising Return to Zero (RZ) signals including digital data. The arrangement includes a comparator, a phase detector, a loop filter, and a voltage controlled oscillator. The phase detector includes a phase position indicator which is activated by each incoming data pulse in the output line of the comparator. A method for recovering clock and data pulses includes the steps of monitoring the data pulses in each output line of the comparator and controlling the voltage controlled oscillator in relation to both edges of each data pulse, for clocking data synchronously with the pulse.

Abstract: In a system for jamming television programs in a cable television system, modified oscillators are used to provide jamming signals to control ports where they are added to the video signal, in order to prevent unauthorized viewing. The oscillators have switchable portions so that they, when receiving appropriate control signals from a control unit on control lines, can be switched to different basic oscillation frequencies and thus each one can cover a very wide frequency range. The basic oscillation frequency of the oscillators is finely adjusted by means of a continuous signal on a line like the conventional voltage control of oscillators. The use of such switched oscillators in an interdiction apparatus for a cable television system provides a number of advantages, such as making the system more flexible and more efficient in terms of jamming capacity for more expensive programs, pay channels, needed oscillator circuitry, etc.