Patent ID: 6400221
Filing Date: 2002-06-04
Classification: H03F

Abstract:
A power amplifier having a frequency selective variable damping factor, said amplifier having an input, an output and a feedback circuit coupled therebetweern, the amplifier for driving a load in the feedback circuit having an impedance which varies with frequency between a high frequency cut-off and a low frequency resonance about a selected frequency comprising:current feedback means in the feedback circuit; first discrete variable impedance means in the feedback circuit to ground for varying overall feedback to the amplifier input as the frequency increases above the selected frequency to vary the response of the amplifier in discrete steps at high frequency; and second discrete tamable impedance means in the feedback circuit between the input and the output for Varying overall feedback to the amplifier input as the frequency decreases below the selected frequency to vary the response of the amplifier in discrete steps at low frequency, said first and second variable impedance means being independently operative with respect, to each other to selectively reduce feedback delivered to the load in said feedback circuit in discrete increments in accordance with its respective impedance and said current feedback means being operative to selectively increase power delivered to the load with changing frequency above and below said selected frequency at the load resonance and the high frequency cut-off.