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AD9634 Recommended for New Designs
The AD9634 is a 12-bit, analog-to-digital converter (ADC) with sampling speeds of up to 250 MSPS. The AD9634 is designed to support communications applications...
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AD9634 on Analog.com

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PN9 testing codes for AD9634



		

			

									
					    alxorlov
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Aug 13, 2012 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hello, everyone!
    
 
    I am unable to find seed value for PN9 sequence. ITU-T standard says, that it should be 0x1ff; AN_877 says 0x092. But none of this equals the code that I get from ADC.
    
 
    Maybe someone can post the seed value and 3-5 first output words?
    
 
    Thanks in advance,
    
 
    Alexander Orlov.
    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 ad9634
                
                                                    
                 High Speed A/D Converters >10 MSPS
                
                                                    
                 Standard High Speed A/D Converters
                
                                
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Aug 13, 2012 7:58 PM
            
            
					
      
	
      

		
		
      
					
      Hi Alexander,
      
 
      I do apologize for the issues you are seeing with the PN9 sequence on the AD9634.  I believe this may be rooted in an digitally inverted output.  I have been investigating this.  As soon as I have an update I will post here for you (and the datasheet will get an update as well).
      
 
      Regards,
      
 
      Jon
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Aug 15, 2012 4:47 PM
            
            
					
      
	
      

		
		
      
					
      Hi Alexander,
      
 
      I think I have the solution for you.  The LFSR has the correct equation for the PN9 sequence, but it is actually a 15 bit LFSR with the 15th bit inverted.  Your output for the 12 bits should be taken from the 14th down to the 3rd flop output (since the output of the converter is 12 bits).  I think if you use these characteristics, you should obtain the right sequence at the output.  Let me know if you have additional questions.
      
 
      Regards,
      
 
      Jon
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
						
				
				
		
		
      
			
		
      
	
      

      

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