Abstract: Apparatus and associated methods relate to generating isolated DC power using a Faraday shielded transformer coupled with an AC/DC power converter. First and second Faraday shields are configured to attenuate capacitive coupling between primary and secondary windings of the Faraday shielded transformer. The first Faraday shield is conductively coupled to a first DC node of the AC/DC power converter. The second Faraday shield is conductively coupled to a second DC node of the AC/DC power converter. In some embodiments, the first and second Faraday shields are associated with the primary and secondary windings, respectively, of the transformer. In some embodiments, two such DC power sources can be used to provide operating power for a circlotron amplifier.

Abstract: An I/Q-modulator or I/Q demodulator circuit in which the modulating signals (2, 3) are input through the output phase transfer branches of the circuit. In relation to the RF-characteristics, a series resistor (16) and a series inductance (20) in the phase transfer circuits are grounded with small capacitors (23, 25). A capacitor (17) having a high impedance at the modulating frequency is located between the branches. Tho modulating signals are not summed through the capacitor (17), and, thus, their phase difference is not weakened.

Abstract: The invention concerns H-bridge type power amplifiers and their blocking means.The memory effect of the capacitive impedance of control inputs of each of the two blocking transistors-in the H-bridge is used to block and unblock the amplifier synchronously with the amplifier input signal: a first switch and a semi-conductor element are placed in parallel with each other, in series with each of these control inputs, such that the blocking of the blocking transistor necessitates the opening of the first switch under the control of the blocking signal, and is dependent on the sign of the charge carried by said capacitive impedance; a second switch controlled by the half periods of the input signal only enables the first switch to close and therefore unblocking of the considered blocking transistor for half periods that are not amplified by this blocking transistor.

Abstract: A carrier rejection circuit for improving carrier rejection in a balanced modulator includes balun transformers, connected to the carrier signal port and the modulated signal port, which reduces parasitic carrier leakage by reducing the average voltages at the ports, offset adjustment circuitry, connected to the modulating signal port, which applies an adjustable offset voltage to the modulating signal to reduce in-phase parasitic carrier leakage and carrier leakage caused by offset voltage at the modulating port, and a reactance network, connected between the carrier signal port and the modulated signal port, for reducing quadrature-phase parasitic carrier leakage.

Abstract: A push-pull modulator stage 70 has two possible transmission paths, an electrically short path (7) and a phase delay path (6) with a phase delay element providing a phase shift of approximately 180.degree.. The phase delay element has the form of a low pass filter. In each of the two paths (6, 7) a semiconductor diode (D.sub.1, D.sub.2) is disposed in such a way that they sense the carrier (U.sub.c) with a phase shift of 180.degree. and, correspondingly, switch in unison if no modulation voltage (U.sub.m) is present, thus suppressing the carrier at the signal output (3). When a modulation signal (U.sub.m) is present, the push-pull balance is disturbed and the resistance of one of the two paths (6) becomes lower relative to the other path (7), which leads to the generation of the modulated carrier voltage (Umc). The modulator stage (70) can also be designed as a dual modulator stage and/or can be used as a mixer stage.

Abstract: A modulator suitable for 16 quadrature amplitude modulation (QAM) is designed as a double modulator (1), wherein a 16 QAM modulator (39) consists of two double modulators (1). One double modulator (1) has two partial modulators (1',1") forming a bridge. Each partial modulator (1',1") has two possible transmission paths: (6',6") with a phase delay line (39',39") which causes a 180.degree. phase shift. On each of the two paths (6',6", 7',7"), a semiconductor diode (D.sub.1 ',D.sub.1 ",D.sub.2 ',D.sub.2 ") is disposed in such a way that they provide the carrier (U.sub.c) with a 180.degree. phase inversion and are accordingly rendered conductive in unison, if no modulation voltage (U.sub.m) is applied, whereby the carrier is suppressed at the signal output (3'). When a modulation signal (U.sub.m) is applied, the balance is changed to push-pull, and one of the two paths (6',6") assumes less impedance compared to the other path (7',7"), which leads to the generation of the modulated carrier voltage (U.sub.mc).

Abstract: A balun section formed of a pair of transmission lines connected between separate pairs of corresponding input and output terminals with a pair of capacitors connected in series between the output terminals and another transmission line connected in series with a resistor between the circuit ground and the interconnection between the pair of capacitors. A multisection balun is constructed from a plurality of such balun sections connected in cascade. In one embodiment, the outputs of a pair of multisection baluns are supplied to a circuit such as a mixer or the like.

Abstract: An RF amplitude modulated amplifier system is presented incorporating a plurality of RF amplifiers which are compensated for unwanted phase modulation. The system includes a common RF driver for supplying a common RF driver signal. A plurality of actuatable RF amplifiers are provided with each having an input circuit for receiving the common RF drive signal. Each amplifier has a fully on condition for amplifying the common drive signal to provide an amplified RF signal, and a fully off condition. Each of these RF amplifiers exhibits a characteristic in that its input circuit has an input impedance which is greater when fully on than that when fully off, thereby tending to present unwanted phase modulation of the plurality of RF amplifiers. One or more of the RF amplifiers are selectively turned fully on in dependence upon the magnitude of an input signal.

Abstract: An microwave device of the diode-operated amplitude modulator or switch type is disclosed. The ring is formed by a source of symmetrical currents which powers the diodes connected to a load. When the diodes are off, they show a capacitance which gives a reactive current. To improve isolation or attenuation, the current in the load must be zero. This is obtained by mounting, on diagonals of the ring, two capacitors which give two currents that are equal and opposite to the two reactive currents.