Abstract: Apparatus for providing a controlled dynamically programmable RF power level to the real part of a terminating load which may vary in impedance over a wide range. Immitance monitoring apparatus produces vector signals representing instantaneous measurements of the voltage and current of an RF signal supplied to a load by an RF generator. These signals which contain information on the phase relationship between the voltage and current are appropriately processed and then multiplied to produce a DC signal which represents the power of the RF signal. The DC signal is employed to control the gain of a variable gain RF amplifier connected between the RF generator and the immittance monitoring apparatus. A feedback control loop is thus provided which controls the power of the RF signal supplied to the load. By amplifying, or attenuating, the signals present at some point in the control loop, the amount of power delivered to the load may be selectively varied.

Abstract: Variable phase shifting apparatus for selectively altering the phase of an AC signal. The signal is conducted through a series of stages. Each stage includes an operational amplifier having an input resistor and a feedback resistor. A capacitor is associated with either the input resistor or with the feed-back resistor. The capacitor may be connected into or disconnected from the stage by a digital switch. When the capacitor is connected, the stage produces a particular amount of shift in the phase of the AC signal, and when the capacitor is disconnected, the AC signal is conducted through the stage with no change in phase. By employing stages capable of producing different amounts of phase shift any of a set of amounts of phase shifts may be obtained.

Abstract: An impedance-matching network for impedance-matching a generator to a load over a wide range of frequencies and impedances. The network includes a first pair of busses across which a plurality of capacitors may be selectively connected to achieve an overall desired value of capacitance for the network, and a second pair of busses across which a plurality of inductors may be selectively connected to achieve an overall desired value of inductance for the network. The network may be controlled so that the capacitance and inductance elements may be arranged with respect to each other and the generator and load in any one of four possible L-type configurations or topologies.

Abstract: Apparatus for monitoring the voltage, current, and phase of an RF signal in a transmission line. A current measuring section having a low input impedance is coupled to the transmission line and employs an isolation amplifier stage of two bipolar transistors in push-pull to produce an output signal representing the current in the RF signal. A voltage measuring section having a high input impedance is coupled to the transmission line and employs an isolation amplifier stage of two field effect transistors in a series cascade arrangement to produce an output signal representing the voltage of the RF signal. The sections include coaxial delay lines of different lengths to compensate for different internal propagation delays so that the phase relationship between the output signals representing voltage and current is the same as in the RF signal being monitored.