How Digital Signal Processing Works @ Digital Grabber News

Lincoln Russell 4 Apr, 2006 at 2:08am ET Article published in Tech

Comments

1. 
   4 Apr 2006 ~ 12:37pm shwaip

   Considering the name, Digital Signal Processing, people are lead towards thinking that this procedure deals with digital signals. No; Digital Signal Processing is a method of improving the quality of the analog signals, only.

   ...not. You can only do DSP on digital signals. Signals have to be quantized at some point before DSP hardware can perform any operations on the signal.
2. 
   4 Apr 2006 ~ 11:20pm Tech Geek That's splitting hairs, the gist of what's said is that the signal was analog, of course you can't perform DSP directly to the analog signal. The quantizing (applying values to a range of input voltages done by an Analog to Digital device)is just one step in performing DSP. One of the easiest methods of DSP to understand is audio effects like echo and reverb.
3. 
   4 Apr 2006 ~ 11:43pm shwaip It's not splitting hairs. It's the difference in the definition of Analog (continuous valued) and Digital (discrete valued) signals, and it seems to me that they have it wrong.
   
   The line "In the digital signals case, we can only compress, encrypt, and translate them to other digital formats" is strictly untrue. All of the processing is done on the digital signals, and none (other than ADC) is done on the analog signal. And if you're starting with an audio file (wav, cd, or otherwise), you never get the analog signal (until you play it), but you can sure as heck throw a filter on the signal.
4. 
   5 Apr 2006 ~ 1:22am Thrax I can sure as hell do DSP transforms on any of my audio files; they're 100% digital until it comes out my speakers.
5. 
   7 Apr 2006 ~ 6:22pm Tech Geek You are technically correct, but you would only perform DSP on data that originated as an analog signal or is a measure of the physical world (such as video which is coded digital from the beginning) to begin with. I didn't say it had to arrive to you being analog, just that it was analog in nature. I have quite a bit of experience with digital filtering. I have worked with FIR and IIR filters, as well as modelling S transforms in the Z domain. I have also designed PI and PID models for controlling analog systems. All my experience lies in the area of digital control systems, and audio, I have no experience with Video DSP.
6. 
   7 Apr 2006 ~ 6:27pm Tech Geek Also shwaip, as to

   but you can sure as heck throw a filter on the signal

   , technically you are not throwing a filter on a "signal". You are running data (timed data samples) through an algorithm, where the output is your filtered data. Whether this data is altered and saved as such, or altered for the purpose of playback in real-time.
7. 
   8 Apr 2006 ~ 1:31pm shwaip ...nothing like arguing from authority...
   
   But we're both arguing semantics, with opinions that differ only slightly, most likely due to having different teachers.
   
   Why can't you consider a timed data sequence to be a signal?