Automatic gain control (AGC) for multichannel/wideband communications system

Abstract

Automatic Gain Control (AGC) system for multi-channel signals attenuates an incoming multi-channel signal by providing a gain. The system further adjusts each individual channel, of the multi-channel signal, by supplying a second gain if needed. The AGC system is designed to ensure a received signal power is at an optimal level for analog to digital conversion or any other form of signal processing. The system also enables elimination of mid-packet gain adjustments.

1 . A multi-channel receiver comprising: 
 an outer programmable gain controller controlling gain of a multi-channel signal; and    a plurality of inner programmable gain controllers, each inner gain controller controlling gain of an individual channel.    
     
     
         2 . The multi-channel receiver of  claim 1 , further comprising an analog to digital converter to digitize the gain controlled multi-channel signal and wherein each channel further comprises a digital filter.  
     
     
         3 . The multi-channel receiver of  claim 1 , wherein the outer gain controller receives feedback from each channel to adjust gain values.  
     
     
         4 . The multi-channel receiver of  claim 3 , wherein the feedback is provided by a modem.  
     
     
         5 . The multi-channel receiver of  claim 3 , wherein the feedback is provided by an analyzer.  
     
     
         6 . The multi-channel receiver of  claim 1 , wherein the outer gain controller supplies a fixed nominal gain while an acquisition threshold power level is not exceeded.  
     
     
         7 . The multi-channel receiver of  claim 6 , wherein once the acquisition threshold power level or a high threshold power level is exceeded, the outer gain controller adjusts the fixed nominal gain such that a total power is brought below the acquisition threshold.  
     
     
         8 . The multi-channel receiver of  claim 1 , wherein the inner gain controller adjusts a gain when an input signal to said inner gain controller differs from a predetermined reference level.  
     
     
         9 . The multi-channel receiver of  claim 1 , wherein the outer programmable gain controller is an analog gain controller.  
     
     
         10 . The multi-channel receiver of  claim 1 , wherein the inner programmable gain controller is a digital gain controller.  
     
     
         11 . A method of automatic gain control for multi-channel communications comprising: 
 automatically controlling gain of a multi-channel signal with an outer programmable gain controller; and    automatically controlling gain of individual channels with a plurality of inner programmable gain controllers.    
     
     
         12 . The method of  claim 11  further comprising: 
 digitizing the gain controlled multi-channel signal with an analog to digital converter, wherein each channel further comprises a digital filter.    
     
     
         13 . The method of  claim 11 , wherein providing an outer gain controller further comprising: 
 receiving feedback from each channel to adjust gain values.    
     
     
         14 . The method of  claim 11  further comprising: 
 supplying a fixed nominal gain, with the use of the outer gain controller, to the multi-channel signal while an acquisition threshold power level is not exceeded; and    adjusting the fixed nominal gain, if the acquisition threshold power level or a high threshold power level is exceeded, such that a total power is brought below the acquisition threshold.    
     
     
         15 . The method of  claim 11  further comprising: 
 adjusting a gain, with the plurality of inner gain controllers, when an input signal to said inner gain controller differs from a predetermined reference level.    
     
     
         16 . The method of  claim 11 , wherein the automatically controlling gain of a multi-channel signal further comprises: 
 controlling an analog gain with the outer programmable gain controller.    
     
     
         17 . The method of  claim 11 , wherein the automatically controlling gain of a individual channels further comprises: 
 controlling a digital gain with the inner programmable gain controller.    
     
     
         18 . A multi-channel receiver comprising: 
 an attenuation gain control means for adjusting gain for a multi-channel signal; and    a plurality of gain control means for adjusting gain of individual channels of the multi-channel signal.    
     
     
         19 . A multi-channel receiver comprising: 
 an outer variable gain amplifier that receives a multi-channel input signal;    an outer analog gain controller that controls the gain applied to the multi-channel input signal;    an analog to digital converter that digitizes the multi-channel input signal after gain adjustment;    a plurality of band pass filters, said filters receiving the multi-channel signal and each filter outputting an individual channel;    a plurality of inner variable gain amplifiers, each receiving a respective individual channel;    a plurality of inner digital gain controllers, each controlling the gain applied to a respective individual channel; and    a plurality of feedback mechanisms providing feedback from respective channels to the outer analog gain controller to adjust gain values.    
     
     
         20 . The multi-channel receiver of  claim 19 , wherein the plurality of feedback mechanisms are modems.  
     
     
         21 . The multi-channel receiver of  claim 19 , wherein the plurality of feedback mechanisms are end point analyzers.  
     
     
         22 . The multi-channel receiver of  claim 19 , wherein the outer gain controller supplies a fixed nominal analog gain while an acquisition threshold power level is not exceeded.  
     
     
         23 . The multi-channel receiver of  claim 22 , wherein once the acquisition threshold power level or a high threshold power level is exceeded, the outer gain controller adjusts the analog gain such that a total power is brought below the acquisition threshold.  
     
     
         24 . The multi-channel receiver of  claim 19 , wherein the inner gain controller adjusts a digital gain when an input signal to said inner gain controller differs from a predetermined reference level.