Abstract: A network simulating an ungrounded inductor includes an active gyrator circuit which employs an operational amplifier, said gyrator being a two port device having an ungrounded port, and a grounded port. The ungrounded port is terminated in a capacitor C so as to provide an input impedance, Zin, looking into the grounded port, which simulates an inductor: Zin=e1/i1=j.omega.R.sup.2 C, where .omega.=2.pi.f, e1 the voltage across the port and i1 is the current into the port. A current i2 is developed in the gyrator circuit, from the operational amplifier output, and appears as an extraneous current at the grounded terminal of the grounded port. An active network including a second operational amplifier is connected to the active gyrator circuit and is arranged to provide a current i3 which is equal in value to but opposite in sign from said i2 current. The current i3 is combined with the i1 and i2 currents at the grounded terminal.

Abstract: Operating power for line signal repeaters is fed over a transmission cable pair (signal line) which is susceptible to lightning strikes and, thus, to longitudinally induced currents in the DC power feed circuit. A symmetrical non-linear power regulator is connected between the signal line and the line signal repeater, and includes a high current shunt regulator which bypasses excessive induced currents. By so doing the adverse effects of these induced currents on the operation of the line signal repeater is minimized. A shunt voltage regulator provides the line repeater with a constant operating voltage when the line current (DC line power feed current plus induced currents) is greater than the minimum required bias current. When the potential at input terminals of the power regulator exceeds a predetermined value, a portion of the excess current is conducted through a blocking diode to charge an energy storage device.

Abstract: A narrow-band RC active bandpass filter, in which the center frequency may be changed by changing the resistance values of certain resistive elements, has the certain resistive elements switchably connectable into and out of the RC network so that the ratio of time during which the resistors are connected to the network to the time during which resistors are not connected to the network determines the effective resistance thereof. A programmable timing circuit has a plurality of outputs with each output supplying a different number of equal width pulses during a predetermined like time period whereby each output corresponds to a different ratio. The timing circuit actuates and deactuates the switchable connection from a selected output thus deriving the required effective resistance for a predetermined center frequency.

Abstract: When connected to a source of unregulated DC power, a series switching regulator delivers a constant output current to a load. A series switch, in response to a control signal, adjusts the flow of input power by switching ON and OFF. The switching operation generates a gated power signal having a variable duty cycle, and the duty cycle depends on the power demands of the load. During the period when the switch is ON, the energy in the gated power signal is stored in the magnetic field of a transformer. During the period when the switch is OFF, the transformer releases the stored energy to capacitive storage devices and to the output load. The capacitive storage devices also supply current to the load when the transformer is storing energy. Feedback signals from voltage and current sensors combine to form a single control signal which adjusts the duty cycle of the switch until the power demands of the load are met.

Abstract: A novel technique for coupling microwave signals to a slot transmission line and for effecting a simultaneous impedance transformation. One lead of a microwave capacitor, connects to a source of microwave signals via a microstrip or coplanar transmission line. The other capacitor lead, located in the same plane as the slot line, crosses the slot line at a right angle and connects to the ground plane on the other side of the slot. A short-circuited segment of the slot line extends N.lambda./4 beyond the point of crossing where N is an odd integer.

Abstract: A microwave signal generator having improved noise spectral characteristics employs a plurality of amplifier-frequency multiplier circuits in combination with a very stable VHF oscillator. Instead of lumping the amplification and frequency multiplication together, each in a single stage, a plurality of amplifiers and multipliers are interleaved, as described herein, resulting in reduced FM noise generation.

Abstract: The disclosed voltage regulator circuit provides a regulated direct output voltage, across first and second output terminals, when an unregulated direct input voltage is applied across first and second input terminals. The second terminals are common to both input and output connections. A voltage reference device, having first and second electrodes, is connected so that the second electrode is connected to the second terminals. A first DC amplifier has an input circuit connected between the first input terminals and the first electrode, and an output circuit connected between the first output terminals and the first electrode. A second DC amplifier has an input circuit connected to the input circuit of the first DC amplifier and an output circuit connected to the output circuit of the first DC amplifier. The second DC amplifier, besides sharing the current load requirements with the first DC amplifier, also controls a bias current through the voltage reference device.

Abstract: A compensation circuit connected across the source and gate electrodes of a MOSFET switch provides a compensating voltage across these electrodes such that the value of the ON resistance, R.sub.ON, from source to drain remains constant despite ambient temperature variations and in the presence of an analog input signal the compensation circuit provides a compensating voltage across these same electrodes such that the value of R.sub.ON remains constant despite variations in the amplitude of the input signal.

Abstract: Apparatus for reducing the susceptibility of line signal repeaters to induced currents includes a zener diode/diode stack which provides the line repeater with a constant voltage drop when the DC line current is above the minimum required bias current. When the DC input current plus an induced component from the line exceed the load requirements of the repeater, the excess current is conducted through a blocking diode to charge an energy storage device. But, when the DC input current and the induced component oppose each other, the energy stored in the energy storage device is used to supplement the input current to just maintain the required repeater voltage.

Abstract: The square-wave output of a comparator is coupled back to the input of an RC controlled integrator including an operational amplifier and an inverter circuit with an output signal maintained at a predetermined level. The RC network sets the pulse repetition rate of the square wave. The inverter and integrator outputs are connected to separate inputs of the comparator. A gating circuit couples a data source to the operational amplifier. In particular, the gating circuit couples an additional square-wave current to the integrator via a resistor. The square-wave current may be in phase and raise the pulse repetition rate of the resulting square wave or out of phase and lower the pulse repetition rate.