Patent ID: 7157988
Filing Date: 2007-01-02
Classification: H03H

Abstract:
1. A voltage variable resistor (VVR) for attenuating a signal, having an input port and an output port for an element of the signal to be attenuated comprising: a certain variable overall impedance, arranged between said input and output ports, consisting of at least a first sub-impedance of a first VVR block, arranged to be controllable by a signal, and a second sub-impedance of a second VVR block, arranged to be controllable by another signal; said first VVR block has a first control input, and said second VVR block has a second control input for coupling control signals to control each of said first and second impedances by means of which at least one of said first and second sub-impedance can be controlled independently; wherein at least one of said first and second TVR blocks comprise semiconductors connected in series for implementing a corresponding one of said first and second sub-impedances and the overall impedance is arranged so as to be variable substantially linearly over a certain value range of a control signal; wherein said second sub-impedance has at least one more series connected semiconductor than said first sub-impedance.