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AD1937 Production
The AD1937 is a high performance, single-chip codec that provides four analog-to-digital converters (ADCs) with differential input and eight digital-to...
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AD1937 on Analog.com

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RMS value to analog output pin

		
	
				

			

									
					    Ferdi_For
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Dec 19, 2018 
				
			
			
		
    
		
		                     
				
        		
    
		    
		    		    
		    			
    
			    
    Hi everyone,
    I'm using the EVAL-ADAU1467Z board and my project concerns the use of the function "Level Detectors". Specifically, I am using the "RTA to Output" which outputs the RMS value. This RMS value is Analog, but it is not an Audio signal.
    

    I learned that the RMS value can be read by "DSP Readback" block.
    

    My question is whether it is possible to connect,inside SigmaStudio Schematic, the RMS (red pin) to an analogue output (of the AD1937, I suppose) in order to read the RMS value as a voltage on a multipurpose (hardware) pin.
    

    Thank you!
    
			
    
			
									
		                             
                        

    
    
                                            
                 Integrated/Special Purpose A/D Converters
                
                                                    
                 Audio CODECs
                
                                                    
                 ad1937
                
                                
            
    
    
    
		
    

				
				        
        		
    
			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		
    

        
        
        
    
					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Super User  
      
            
						
                            
            
            				
            
                on Dec 20, 2018 11:22 AM
            
            
						
			            		
      
		
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           Absolutely you can!  I just tried it on my ADAU1466 eval board.  Connecting a DC Source to the I2S output to the on-board AD1938 codec, I got these measurements:
      

      DC Src  Output:
      

      -1            0.28
      

      -0.5         0.90
      

      0             1.53
      

      0.5          2.15
      

      1             2.77
      

      

           If your micro runs on 3.3V these values are ideal for its ADC.  The codec is designed for audio, not for instrumentation -- so I suggest you have your micro run a sort of auto-cal scheme at power-up -- where it puts known input(s) through the DAC and notes the results.  On a mixer we produced, we found that a simple one-point cal at the bottom end of the level scale (where accuracy is important in dB terms) was sufficient.
      

      

           Best regards,
      

           Bob
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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