• State Verified Answer
  • Replies 3 replies
  • Subscribers 40 subscribers
  • Views 217 views
  • Users 0 members are here
Options 

        

            Post
             Go back to editing
        

    

    


    

    









		


















	
	
			
	
			
		
	
	
		

		
Different Tx power in consecutive repeatTransmit executions, with the same exact settings (Adalm Pluto)



		

			

									
					    arquelaus
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Nov 12, 2024 
				
			
			
		
    

				
		
    
		    		    
		    
		    		      		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  adalm pluto 
    
    		        		    		    	
			
    I am seeing that, each time I do a repeatTransmit (under the same configuration), I observe different output levels, apparently in a random way. Both output levels are influenced by the Attenuation selected. For example, the plots below are two consecutive executions of the same Matlab code:
    

    Example with "low" output power:
    

     
    

    Example with "high" output power
    

     
    

    What is the origin of this? Is this indicating a HW problem? 
    

    I would be very grateful for any guidance understanding what is happening here.
    

    Best regards,
    
									
			                
    Thread Notes   
    
        
    
        
            
		
    

				
						
        

    
    Tags: 
                                            
                 distortion
                
                                                    
                 hardware
                
                                                    
                 tx
                
                                                    
                 adalm
                
                                                    
                 pluto
                
                                        
                                            
                
                
                                
                    Show More
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			








	
	
	
	



Parents
	
      
	

    • 
	
      



	
		
	
	



      
	
      
		
      
							
					
      
		
      
			
													0
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Nov 12, 2024 6:11 PM
            
            
					
      
	
      

		
		
      
					
      Can you try setting the Frequency in band on your dsp.SineWave object? You are generating a baseband signal for the radio so it needs to be < fs/2.
      

      -Travis
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

      • 

	

    • 
	
      



	
		
	
	



      
	
      
		
      
							
					
      
		
      
			
													0
							
			
				
									
							        
			
			
			
        
            
						
                            
            
            				
            
                on Nov 12, 2024 6:53 PM
            
            
												
						in reply to travisfcollins
					
									
        
	
        

		
		
        
					
        Hi Travis, thank you for your suggestion & prompt response. Selecting an in-band frequency provides the same inconsistent output power between runs. I am using the following code:
        

        txGain = -50;
        

        

        Fs = 3e6;
        

        fc = 1.290e9;
        

        

        

        tx = sdrtx(deviceNameSDR);
        

        tx.RadioID = 'ip:192.168.2.1';
        

        

        tx.CenterFrequency = 1.290e9;
        

        tx.BasebandSampleRate = Fs;
        

        tx.Gain = txGain;
        

        

        

        sw = dsp.SineWave;
        

        sw.Amplitude = 10;
        

        sw.Frequency = Fs/4;
        

        sw.ComplexOutput = true;
        

        sw.SampleRate = Fs;
        

        sw.SamplesPerFrame = 20000; 
        

        txWaveform = sw();
        

        

        

        

        

        transmitRepeat(tx,txWaveform);
        

        

        

        

        release(tx);
        

        

        
Any further idea? I also tried DDS with the same result.
        

        

        Thanks again for your help.
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

        • 

	
      



Reply

        


      • 
	
        



	
		
	
	



        
	
        
		
        
							
					
        
		
        
			
													0
							
			
				
									
							        
			
			
			
          
            
						
                            
            
            				
            
                on Nov 12, 2024 6:53 PM
            
            
												
						in reply to travisfcollins
					
									
          
	
          

		
		
          
					
          Hi Travis, thank you for your suggestion & prompt response. Selecting an in-band frequency provides the same inconsistent output power between runs. I am using the following code:
          

          txGain = -50;
          

          

          Fs = 3e6;
          

          fc = 1.290e9;
          

          

          

          tx = sdrtx(deviceNameSDR);
          

          tx.RadioID = 'ip:192.168.2.1';
          

          

          tx.CenterFrequency = 1.290e9;
          

          tx.BasebandSampleRate = Fs;
          

          tx.Gain = txGain;
          

          

          

          sw = dsp.SineWave;
          

          sw.Amplitude = 10;
          

          sw.Frequency = Fs/4;
          

          sw.ComplexOutput = true;
          

          sw.SampleRate = Fs;
          

          sw.SamplesPerFrame = 20000; 
          

          txWaveform = sw();
          

          

          

          

          

          transmitRepeat(tx,txWaveform);
          

          

          

          

          release(tx);
          

          

          
Any further idea? I also tried DDS with the same result.
          

          

          Thanks again for your help.
          
			
          

		
			
	      

		
		
	
          
	
          
		
          
			
		
          
	
          
	
          
		
						
						
				
						
				
				
		
		
          
			
		
          
	
          

          

          • 


        


Children
	
        No Data