Patent ID: 8238862
Filing Date: 2012-08-07
Classification: H03F,H03H,H04B

Abstract:
1. A frequency translated notch filter, comprising: a passive mixer configured to mix a radio frequency (RF) signal received at a first mixer input and a local oscillator (LO) signal received at a second mixer input; and a baseband impedance coupled between an output of the passive mixer and ground, the baseband impedance comprising a capacitor implemented using a metal-oxide semiconductor (MOS) capacitor, wherein a drain to gate voltage of the MOS capacitor is biased to provide a substantially constant capacitance over changes in the RF signal, wherein the first mixer input presents a high-impedance path to ground for frequency components of the RF signal within a desired frequency band and a low-impedance path to ground for frequency components of the RF signal outside the desired frequency band.