# Oversampling & Dithering



## Megalomaniac (Feb 12, 2007)

I am not understanding the difference between oversampling and dither, the instructor here at school is still not clear enough for me to understand. 

From my understanding as of right now, oversampling makes educated guesses in the D/A process to correct/predict dropped bits fro a broad point of view.

And dithering corrects dropped bits during the oversampling process in a much smaller aspect, small enough to where the Oversampling can not register it as a sample at all, so it requires dithering.


 Please clarify, thanks.


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## ViperVin (Mar 15, 2008)

I have no clue. But I am good with google. 

Oversampling - Wikipedia, the free encyclopedia
Dither - Wikipedia, the free encyclopedia


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## Megalomaniac (Feb 12, 2007)

I got a good reply on a different forum here is what i responded:



solacedagony said:


> DFW Sound pro audio glossary - Sound Systems, Stage, and Lighting...Quality sound systems, lighting, staging and production needs in the Dallas, Fort Worth, Texas, TX, metroplex area.
> 
> *Over-sampling* - In a digital device, the input analog signal is sampled at a much higher rate than the normal sampling rate. Using the high sample rate, the digital data may be processed with a very steep slope digital filter. As the filter is in the digital domain, unpleasant side-effects, such as phase effects are eliminated.
> 
> *Dither* - In digital recording and signal processing, dithering is a mathematical process where a random noise is added to the least significant bit of a digital word. With very low level signals, the quantization error becomes correlated to the signal level. This creates a measurable amount of distortion. By adding dither, the correlation between the signal level and the quantization error is canceled, allowing the digital system to encode amplitudes smaller than the least significant bit. If you change the word size as a signal passes from one digital system to another, being able to add dither allows you to maintain a high quality signal.





Megalomaniac said:


> Wow that definition is better than the book I am using for the class.
> 
> I overlooked that part. So the sample rate is 44.1k and with a slope after 22k(or the point of Nyquist) so it can degrade naturally since if it were a 22k sample bits would drop before that; a brickwall does not exist to filter this out.
> 
> and for Dithering it just adds noise floor so the voltage can register as a signal for the analog since its too low?


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## ItalynStylion (May 3, 2008)

Over sampling sounds like what an upscaling DVD player does to regular DVDs for a 1080p screen.


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## Megalomaniac (Feb 12, 2007)

ItalynStylion said:


> Over sampling sounds like what an upscaling DVD player does to regular DVDs for a 1080p screen.


wouldnt that jump into multiplexing? or is that just compression


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## ItalynStylion (May 3, 2008)

Megalomaniac said:


> wouldnt that jump into multiplexing? or is that just compression


<-----marketing major hasn't a clue. 


The idea that you presented reminded me of upscaling only for audio.


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