Receiver apparatus having filters implemented using frequency translation techniques

摘要

A method and apparatus is disclosed to effectively frequency translate a filter characterized as a low quality factor (Q) filter corresponding to a baseband frequency of approximately zero Hertz or to an intermediate frequency (IF) to a filter characterized as a high Q filter at frequencies greater than the baseband frequency or the IF. A downconversion mixer is used to frequency translate a communication signal to the baseband frequency or the IF using a first local oscillator signal to provide a downconverted communication signal. A filter characterized as the low Q filter corresponding to the baseband frequency or the IF filters the downconverted communication signal to provide a filtered communication signal. An upconversion mixer is used to frequency translate a communication signal using a second local oscillator signal, the second local oscillator signal being substantially similar in frequency of the first local oscillator signal. The frequency translation by the upconversion mixer, in effect, translates the filter characterization from the low Q filter to the high Q filter at frequencies greater than the baseband frequency or the IF.