Talk:Continuously variable slope delta modulation

I removed the statement that "CVSD" is a 'lossy codec'. It is not really a codec, it's a modulation scheme so the term doesn't apply here. You can't say that an analog to digital step is a 'lossy codec', though it is correct that going from the analog to digital domain does introduce noise.

Call it a coder instead of a codec, then? I called it lossy because if you take uncompressed PCM data, run it through a CVSD coder, and then run that through a CVSD decoder, the PCM output you get does not match the original input. This is in contrast to FLAC, Apple Lossless, or even LZW compression, etc. where the uncompressed output is always bit-for-bit equal to the original input.

CVSD coding introduces more noise than a simple analog to digital conversion, or even some companding schemes like mu-law and A-law. Calling it a "lossy codec" seemed to be the least verbose way to indicate that CVSD will not store an exact representation of the input signal. Pfagerburg (talk) 02:36, 9 September 2008 (UTC)

I added new text to explain that the decoded audio will not match the original signal, without calling CVSD a codec or calling it lossy. I hope that this verbiage will be acceptable. Some people really care about lossless audio coding, and so I think it's important to note when a coder, codec, or companding algorithm does not produce an decoded output that matches the original input to the encoder. Pfagerburg (talk) 03:56, 9 September 2008 (UTC)

ADM and CVSDM

What is the relation between them? --User:Vanished user 8ij3r8jwefi 16:36, 7 February 2008 (UTC)

ADM is the same as CVSD, see [1]: "... Robust ADM coding (e.g. CVSD) ..." Pfagerburg (talk) 03:50, 9 September 2008 (UTC)

CVSD was developed for Secure Voice Communications by the NSA. NSA taught the science and theory to many Top-Secret "Crypto Maintenance Technicians" within the DOD and other agencies during early '80's. The original cryptologic principle is still classified. The equipment was built extremely durable for both fixed station or tactical environments. The secure voice telephony system was also gray in color. This is or was the common color within a SCIF. A SCIF was the only place to use the commonly called-CVSD TELEPHONE SYSTEM.

The CVSD theory "only" was shared with general business telecomm arena after the iron curtain fell and capitalists finally dominated our planet earth. —Preceding unsigned comment added by Tybo61 (talk • contribs) 00:13, 3 April 2009 (UTC)

Quantization noise claim

I removed the claim that CVSD reduces quantization noise by more closely approximately the input signal. Quantization noise is more a function of the ADC stage, not the voice coder itself. The grammar in the claim was poor, and so I may have misunderstood the claim. In that case, please feel free to re-add it in a better form, preferably with a reference to back it up. —Preceding unsigned comment added by Pfagerburg (talk • contribs) 21:35, 31 May 2009 (UTC)