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Get in RX the same values of TX

		
	
				

			

									
					    Daniel_Camara
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Apr 22, 2015 
				
			
			
		

		
		                     
				
        		

		    
		    		    
		    			

			    
Hi people,

 
There is a way to send a data in the TX and receive the same in the RX?  I mean if I put a cable between TX A and RX A and send a value in I and another in Q, there is a way to get them back on the RX A I/Q?  I am developing a IEEE 802.15.4 transceiver, and for testing, at least in the begging would be nice to be able to do that, send something and get the same the other side. 

 
 I tried to change the ad9361-iiostream.c to send always the same data, RX and TX in the same frequency, and on the RX compare the received I/Q to see if was the same... but I didn't manage to do it.  Well it makes sense not being able to, the process is too fast, so the time you say send this and you start reading it is possible that you will not read the same thing you just sent, even more because, as far as I understood the buffers in the middle would make this  synchronization a nightmare, even with different threads for the send and receive. 

 
 Nevertheless, I would know if I can do it, somehow to be able to test my transceiver. 

 
   Best regards...

 
          Daniel

			

			
									
		                             
                        
		


				
				        
        		

			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		


        
        
        
    
					

			





















	

	

					



			








	
	
	
	



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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Apr 24, 2015 1:21 AM
            
            
						
			            		
    
		
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    Daniel,
    
 
    Don't confuse things - Loopback has nothing todo with buffers.
    
 
    Loopback happens on the interface level internal to the AD9361. No single bit will be lost.
    
 
    What you are seeing can be related to libiio buffers. There are cyclic buffers that repeat over and over again.
    
 
    Non-Cyclic streaming buffers, if you can't push fast enough you will also see that the last sample(s) will be repeated, until new data is pushed.
    
 
    So make your buffers big enough to reduce management overhead. If necessary you may need to reduce the sample rate.
    
 
    -Michael
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Apr 24, 2015 1:21 AM
            
            
						
			            		
    
		
										0
					
	
    

		
		
    
		
    
                                
                                                            
    
					
    Daniel,
    
 
    Don't confuse things - Loopback has nothing todo with buffers.
    
 
    Loopback happens on the interface level internal to the AD9361. No single bit will be lost.
    
 
    What you are seeing can be related to libiio buffers. There are cyclic buffers that repeat over and over again.
    
 
    Non-Cyclic streaming buffers, if you can't push fast enough you will also see that the last sample(s) will be repeated, until new data is pushed.
    
 
    So make your buffers big enough to reduce management overhead. If necessary you may need to reduce the sample rate.
    
 
    -Michael
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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