Hybrid receiver architecture using upconversion followed by direct downconversion

Abstract

A receiver configured to selectively receive an RF signal from an operating band having a plurality of RF channels. The receiver is configured to upconvert the desired RF channel to an intermediate frequency (IF) greater than the RF channel frequencies. The upconverted RF channel is downconverted to baseband or a low IF. The receiver can perform channel selection by filtering the baseband or low IF signal. The baseband or low IF signal can be upconverted to a programmable output IF.

1 . A receiver comprising: 
 an upconverter configured to frequency convert an input signal to an intermediate frequency signal in a frequency band greater than at least a portion of an input signal frequency band;    a downconverter coupled to the upconverter and configured to frequency convert the intermediate frequency signal to a baseband signal; and    a filter coupled to the downconverter and configured to filter the baseband signal.    
   
   
       2 . The receiver of  claim 1 , wherein the intermediate frequency signal comprises a fixed frequency signal.  
   
   
       3 . The receiver of  claim 1 , wherein the intermediate frequency signal comprises a programmable frequency signal.  
   
   
       4 . The receiver of  claim 1 , further comprising an output upconverter coupled to the filter and configured to upconvert a filtered signal to an output frequency.  
   
   
       5 . The receiver of  claim 1 , wherein the downconverter comprises a quadrature downconverter configured to direct downconvert the intermediate frequency signal to in-phase and quadrature baseband signal components.  
   
   
       6 . The receiver of  claim 1 , further comprising a first filter coupled to an output of the upconverter and configured to perform band select filtering of an upconverted signal.  
   
   
       7 . The receiver of  claim 1 , wherein the filter is configured to perform channel selection filtering of the baseband signal.  
   
   
       8 . The receiver of  claim 1 , further comprising a analog to digital converter (ADC) coupled to the filter and configured to digitize the baseband signal.  
   
   
       9 . A receiver comprising: 
 a first upconverter configured to upconvert a desired RF signal to a first Intermediate Frequency (IF) that is greater than a frequency of the desired RF signal;    a filter coupled to the upconverter and configured to perform band selection filtering of a signal output by the upconverter to generate a filtered upconverted signal;    a quadrature direct downconverter configured to downconvert a desired signal in the filtered upconverted signal to in-phase and quadrature signal components;    a first filter coupled to the quadrature direct downconverter and configured to perform channel selection filtering on the in-phase signal component;    a second filter coupled to the quadrature direct downconverter and configured to perform channel selection filtering on the quadrature signal component;    a second upconverter coupled to the first and second filters and configured to upconvert the filtered in-phase and quadrature signal components to in-phase and quadrature output IF signal components; and    a signal combiner coupled to the second upconverter and configured to combine the in-phase and quadrature output IF signal components.    
   
   
       10 . The receiver of  claim 9 , wherein the second upconverter comprises a digital upconverter configured to digitally upconvert the filtered in-phase and quadrature signal components.  
   
   
       11 . The receiver of  claim 9 , wherein the desired RF signal comprises an analog television signal.  
   
   
       12 . The receiver of  claim 9 , wherein the desired RF signal comprises a digital television signal.  
   
   
       13 . A method of processing a received signal, the method comprising: 
 upconverting a desired input signal to a first intermediate frequency (IF) signal at a frequency greater than a frequency of the desired input signal;    downconverting the first IF signal to a baseband signal; and    performing channel selection on the baseband signal.    
   
   
       14 . The method of  claim 13 , further comprising filtering the first IF signal to select a desired band of signals.  
   
   
       15 . The method of  claim 13 , further comprising upconverting the baseband signal to a desired output IF following channel selection.  
   
   
       16 . The method of  claim 13 , wherein downconverting the first IF signal comprises direct quadrature downconverting the first IF signal to an in-phase baseband signal component and a quadrature baseband signal component.  
   
   
       17 . The method of  claim 13 , wherein performing channel selection comprises filtering each of an in-phase baseband signal component and a quadrature baseband signal component.  
   
   
       18 . A method of processing a received signal, the method comprising: 
 selecting a desired television signal at a desired RF channel;    upconverting the desired television signal to a first Intermediate Frequency (IF) that is greater than a frequency of the desired RF channel;    direct downconverting the desired television signal from the first IF to in-phase and quadrature signal components;    performing channel selection filtering on each of the in-phase and quadrature signal components;    upconverting the in-phase and quadrature signal components to second IF in-phase and quadrature signal components at a desired second IF; and    combining the second IF in-phase and quadrature signal components to generate the desired television signal at the second IF.    
   
   
       19 . The method of  claim 18 , further comprising digitizing each of the in-phase and quadrature signal components, and wherein channel selection filtering comprises digital filtering.  
   
   
       20 . The method of  claim 18 , wherein the in-phase and quadrature signal components comprise an in-phase baseband signal component and a quadrature baseband signal component.  
   
   
       21 . The method of  claim 18 , wherein the in-phase and quadrature signal components comprise an in-phase low IF signal component and a quadrature low IF signal component.