26-04-2012 дата публикации
Номер: US20120099686A1
An agile RF tuner circuit capable of converting a wide portion of RF signal into an IF signal suitable for analog-to-digital conversion. The circuit up converts a received RF signal to a high IF signal and then down converts the high IF signal to a low IF signal. Embodiments of the RF circuit incorporate harmonic reject mixers to suppress harmonics and intermodulations typically associated with the frequency conversion process. 1. A method for converting a wide portion of a received RF signal into an IF signal , said method comprising:processing said RF signal in continuous fashion;frequency translating said processed RF signal to a low IF signal, said low IF signal comprising an in-phase component and a quadrature component, wherein frequency translating said processed RF signal to a low IF signal is accomplished, at least in part, by mixing said RF signal with a plurality of harmonic reject mixers;lowpass filtering the in-phase and quadrature components of said low IF signal; andconverting said in-phase and quadrature components to a digital signal.2. The method of further comprising frequency translating each of said in-phase and quadrature components of said low IF signal to a high IF signal having in-phase and quadrature components prior to said converting said in-phase and quadrature components to a digital signal.3. The method of wherein said processing said RF signal comprises bandpass filtering said RF signal with a filter comprising a switched filter structure with analog trim.4. The method of wherein said harmonic reject mixers operate on said RF signal to suppress harmonics associated with said harmonic reject mixers.5. The method of wherein said plurality of harmonic reject mixers comprises a first mixer stage and a second mixer stage.6. The method of wherein said first mixer stage generates said in-phase components of said low IF signal.7. The method of wherein said second mixer stage generates said quadrature component of said low IF signal.8. The ...
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