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AD9361 Recommended for New Designs
The AD9361 is a high performance, highly integrated radio frequency (RF) Agile Transceiverâ„¢ designed for use in 3G and 4G base station applications....
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AD9361 on Analog.com

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why the received Q signal is always distorted?

		
	
				

			

									
					    xiaoquan
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Mar 12, 2018 
				
			
			
		

		
		                     
				
        		

		    
		    		    
		    			

			    
Hi,

 
when I implement QPSK signal transmit-receive by ad9361, the result is out of my expectation. By ILA IP, the tx_signal and rx_signal are shown as follow,

 

 
it can be viewed that Q signal is distorted totally.

 
then from SDK, I use function ad9361_bist_loopback(ad9361_phy, 1)  to implement the loopback tx to rx in ad9361. the signals  are shown below,

 

 
Q signal is still not right. (ADI provided reference HDL design and no-OS platform are adopted)Can you help me?

 
thanks in advance,

 
xiao quan

			

			
									
		                             
                        

    

                                            
                 iq signal
                
                                                    
                 ad9361
                
                                                    
                 Wideband Transceiver IC
                
                                                    
                 RF Integrated Transceivers
                
                                
            

    
    
		


				
				        
        		

			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		


        
        
        
    
					

			





















	

	

					



			








	
	
	
	



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                on Mar 12, 2018 2:08 PM
            
            
						
			            		
    
		
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    hello Michael,
    
 
    Thank you very much! what you said is truly a possible case for this phenomenon. But I want to know that whether DAC_SEL_DDS can be set to Q channel  independently, and I channel is set to DAC_SEL_DMA  in one tx path?  In SDK, I write a statement dac_datasel(ad9361_phy,0,DATA_SEL_DMA); in main.c after AD9361 is initialized.
    
 
    thanks,
    
 
    xiao quan
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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                on Mar 12, 2018 2:08 PM
            
            
						
			            		
    
		
										0
					
	
    

		
		
    
		
    
                                
                                                            
    
					
    hello Michael,
    
 
    Thank you very much! what you said is truly a possible case for this phenomenon. But I want to know that whether DAC_SEL_DDS can be set to Q channel  independently, and I channel is set to DAC_SEL_DMA  in one tx path?  In SDK, I write a statement dac_datasel(ad9361_phy,0,DATA_SEL_DMA); in main.c after AD9361 is initialized.
    
 
    thanks,
    
 
    xiao quan
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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