Use of a preselection filter bank and switched local oscillator counter in an instrumentation receiver

Abstract

An instrumentation receiver architecture for processing an RF signal has a dual-IF channel architecture, a low-band IF channel and a high-band IF channel, and a tunable oscillator, such as a yttrium-iron-garnet (YIG) tunable oscillator (YTO), a voltage controlled oscillator (VCO), a bank of VCOs and the like, providing a different mixing frequency range to each channel, generally a higher frequency range to the high-band IF channel than to the low-band IF channel. At the input to the high-band IF channel is a bank of preselection filters for selecting a frequency band from the RF signal for processing by the high-band IF channel. A switch selects the output from one of the low-band and high-band IF channels for further processing.

1 . An instrument receiver architecture comprising: 
 a low-band IF channel having as an input an RF signal and providing as an output a low-band IF signal;    a bank of preselection filters having as an input the RF signal and providing as an output a selected frequency band of the RF signal;    a high-band IF channel having as an input the selected frequency band and providing as an output a high-band IF signal; and    means for selecting one of the low-band and high-band IF signals for further processing.    
   
   
       2 . The architecture as recited in  claim 1  wherein the low-band IF channel comprises: 
 an up-converting stage having the RF signal as an input and providing as an output a first IF signal; and    a down-converting stage having the first IF signal as an input and providing as an output a second IF signal, the second IF signal being the low-band IF signal for input to the selecting means.    
   
   
       3 . The architecture as recited in  claim 2  wherein the high-band IF channel comprises a hi-band down-converting stage having as an input the selected frequency band and providing as an output the high-band IF signal for input to the selecting means, the high-band IF signal having the same intermediate frequency as the low-band IF signal.  
   
   
       4 . The architecture as recited in  claim 1  wherein the low-band IF channel comprises an up-converting stage having as an input the RF signal and providing as an output the low-band IF signal for input to the selecting means.  
   
   
       5 . The architecture as recited in  claim 4  wherein the high-band IF channel comprises a down-converting stage having as an input the selected frequency band and providing as an output the high-band IF signal for input to the selecting means, the low-band and high-ban IF signals having different intermediate frequencies.  
   
   
       6 . The architecture as recited in  claim 5  further comprising an output down-converting stage coupled to the selecting means, the output down-converting stage being configurable to convert both the low-band and high-band IF signals to a common IF signal for further processing.  
   
   
       7 . The architecture as recited in  claim 6  wherein the output down-converting stage comprises: 
 a mixer having an input coupled to the selecting means and providing as an output the common IF signal;    a local oscillator providing a first local oscillator signal for mixing with the low-band IF signal when selected by the selecting means and a second local oscillator signal for mixing with the high-band IF signal when selected by the selecting means, the first local oscillator signal having a frequency higher than the frequency of the second local oscillator signal and the low-band IF signal having a higher intermediate frequency than the high-band IF signal.    
   
   
       8 . The architecture as recited in  claim 7  wherein the local oscillator comprises: 
 an oscillator having as an output the first local oscillator signal; and    means for deriving the second local oscillator signal from the first local oscillator signal.    
   
   
       9 . The architecture as recited in  claim 8  wherein the deriving means comprises a divider having as an input the first local oscillator signal and having as an output the second local oscillator signal.  
   
   
       10 . The architecture as recited in  claim 1  wherein the low-band IF channel comprises: 
 a low-band bank of preselection filters having as an input the RF signal and providing as an output a selected frequency band of the RF signal; and    a low-band converter stage having as an input a selected one of the RF signal and the selected frequency band and having as an output the low-band IF signal for input to the selecting means, the low-band converter stage operating as an up-converting stage when the input is the RF signal to produce an up-converted low-band IF signal as the low-band IF signal and operating as a low-band down-converting stage when the input is the selected frequency band to produce a down-converted low-band IF signal as the low-band IF signal.    
   
   
       11 . The architecture as recited in  claim 10  wherein the high-band IF channel comprises a down-converting stage having as an input the selected frequency band and providing as an output the high-band IF signal for input to the selecting means.  
   
   
       12 . The architecture as recited in  claim 11  wherein the selecting means comprises: 
 a first means for selecting as an output one of the high-band IF signal and the down-converted low-band IF signal; and    a second means for selecting as an output one of the high-band IF signal and the up-converted low-band IF signal.    
   
   
       13 . The architecture as recited in  claim 12  further comprising an output down-converting stage for converting the output from the first and second selecting means to a common IF signal for further processing.  
   
   
       14 . The architecture as recited in  claim 13  wherein the output down-converting stage comprises: 
 a mixer having as an input the output from the first and second selecting means and providing as an output the common IF signal;    a local oscillator providing as outputs a first local oscillator signal for mixing with the up-converted low-band IF signal when selected by the first and second selecting means to produce the common IF signal and a second local oscillator signal for mixing with the selected one of the high-band IF signal and the down-converted low-band IF signal when selected by the first and second selecting means to produce the common IF signal, the first local oscillator signal having a frequency higher than the frequency of the second local oscillator signal and the up-converted low-band IF signal having a higher intermediate frequency than the down-converted low-band and high-band IF signals.    
   
   
       15 . The architecture as recited in  claim 14  wherein the local oscillator comprises: 
 an oscillator having as an output the first local oscillator signal; and    means for deriving the second local oscillator signal from the first local oscillator signal.    
   
   
       16 . The architecture as recited in  claim 15  wherein the deriving means comprises a divider as an input having the first local oscillator signal and having as an output the second local oscillator signal.  
   
   
       17 . The architecture as recited in any of claims  1 - 16  further comprising a tunable local oscillator having as outputs a first oscillator frequency signal for input to the low-band IF channel to produce the low-band IF signal and a second oscillator frequency signal for input to the high-band IF channel to produce the high-band IF signal, the second local oscillator frequency signal having a frequency that is higher than the frequency of the first local oscillator frequency signal.  
   
   
       18 . The architecture as recited in  claim 17  wherein the tunable local oscillator comprises: 
 a YIG tunable oscillator having as an output the second oscillator frequency signal; and    means for deriving the first oscillator frequency signal from the second oscillator frequency signal.    
   
   
       19 . The architecture as recited in  claim 18  wherein the deriving means comprises a divider having as an input the second oscillator frequency signal and having as an output the first oscillator frequency signal.