Patent ID: 6933746
Filing Date: 2005-08-23
Classification: H03K,H04L

Abstract:
1. A control device responsive to control signals for electrically coupling an input node configured for connection to a low impedance source to an output node configured for connection to a transmission line, the control device including: a first controlled impedance device having a pair of controlled nodes connected between the input node and the output node, the first controlled impedance device having a control node for controlling impedance values between the controlled nodes; a second controlled impedance device, similar to the first controlled impedance device, and having a pair of controlled nodes and a control node, the second controlled impedance device having an impedance variation characteristic that is related to an impedance characteristic associated with the first controlled impedance device; a closed loop control circuit connected to the control node of the second controlled impedance device for providing a compensation signal to the control node of the second controlled impedance device based on impedance variation of the second controlled impedance device relative to a reference; and wherein the closed loop control circuit is connected to the control node of the first controlled impedance device to provide compensation for the first controlled impedance based on the compensation for the second controlled impedance device.