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Talk:Differential pulse-code modulation

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Latest comment: 8 years ago by 130.75.31.216 in topic Entropy is not reduced

May 2009

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Djpark0115 (talk) 07:00, 21 May 2009 (UTC) Q-1 is necessary in the encoder/ecoder diagram of option2 ??Reply

Yes, good catch; it's needed in the type 2 encoder as well. Maybe you can alert the editor who made the figure... Dicklyon (talk) 17:19, 21 May 2009 (UTC)Reply

Q-1 is horribly wrong! Quantization is not invertible. Option 1 is only possible if no quantization is done and the compression algorithm is lossless. The whole article has a lot of errors. — Preceding unsigned comment added by 188.155.108.64 (talk • contribs)

You were right to remove the bad figure from option 1. I edited the text to make it correct, I think. Dicklyon (talk) 18:07, 8 January 2011 (UTC)Reply

Please make it more 'audible'

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Please explain the roles of Z-1, the circuitry. —Preceding unsigned comment added by Piotroxp (talk • contribs) 06:51, 19 June 2009 (UTC)Reply

I noted in the article that it represents a sample delay; it's obscure conventional DSP notation based on the Z transform. Dicklyon (talk) 18:16, 8 January 2011 (UTC)Reply

Local model

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what does "local model" means in the option 2 section? --190.60.93.218 (talk) 18:53, 29 May 2014 (UTC)Reply

Entropy is not reduced

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Hello,

the statement "because the entropy of the difference signal is much smaller than that of the original discrete signal" is wrong. The idea of a DPCM is to reduce the variance by building a difference signal. The entropy is not reduced (it is not changed at all by calculating the difference signal). Entropy is only reduced in the quantized signal (obviously). — Preceding unsigned comment added by 130.75.31.216 (talk) 09:21, 20 August 2018 (UTC)Reply