Patent ID: 7602221
Filing Date: 2009-10-13
Classification: H03B

Abstract:
1. An integrated circuit comprising: a level shift having first and second inputs and first and second outputs, wherein the first input of the level shift is coupled to an input signal; a double mixer having first, second and third inputs and an output, wherein the first input of the double mixer is coupled to the first output of the level shift and wherein the second input of the double mixer is coupled to the second output of the level shift; a filter having first and second inputs and first and second outputs, wherein the output of the double mixer is coupled to the first input of the filter, and wherein the first output of the filter is looped back to the third input of the double mixer; and a buffer having an input and an output, the buffer operable to buffer and output at least an output signal, wherein the input of the buffer is coupled to the second output of the filter, wherein the filter is tunable to a predetermined frequency range by an adjustable reference voltage coupled to the buffer.