<< 回到测试与测量  
     
  Audio Test and Measurement Applications  
     
  Education  
     

A picture is worth 1000 words. Discuss.
If you want to see and understand audio concepts, a visual display of what is happening is the way to go. There's nothing quite like being able to see a waveform, its frequency spectrum, readings, bar-graphs, filters and more, all at once, and to hear the signal you are working on, all with real-time interaction.

 
     
   
  Comparison of FFT windows and their resulting spectra with a sine wave  
     
  Worked Example
Question: Explain the difference between THD+N and THD. Use words if necessary.

Answer:

 
   
   
     
  Heading into the unknown: user defined soft instruments
And what if you're doing a research project in audio? You may want to make a measurement that no-one has ever done before. dScope Series III may well be the way to do it. From its automation interface you can get at the sample buffers and the FFT magnitude and phase buffers, pre and post weighting filters. From there you can do what you like with the data - transform it, process it, extract data. The user defined FFT detector can be programmed to return a result that can then be used as any other FFT detector result: it can be swept, limit checked, used in regulation routines, etc. etc.
 
     
   
  dScope Series III user programmed FFT detector showing the ratio of odd to even harmonics