Patent ID: 7586385
Filing Date: 2009-09-08
Classification: H03H,H03J

Abstract:
1. A tuning circuit for dynamically varying the impedance of a tank circuit comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the tuning circuit comprising: a reference voltage generator, coupled to the tank circuit, to produce a reference voltage proportional to the response of the tank circuit to a received signal, wherein the voltage generator comprises: a differentiator, coupled to the generator, to determine a polarity of the change in the reference voltage between a first point in time and a second point in time, wherein the differentiator comprises: a direction selector, coupled to the differentiator, to select one of said first and second directions in response to said polarity, wherein the direction selector comprises: a ramp generator, coupled to the selector and to the capacitor, to selectively vary the capacitance of said capacitor in said selected direction, wherein the ramp generator comprises: