basic question on sigma-delta AD converter

[Robertt]

I know the structure of ∑Δ modulator, but why call it sigma and delta? what sigma means and what delta means?

Is that just because plus the reference voltage sometimes and substract reference sometimes?

 

[ocarnu]

I think is becuase you substract the error (-) and integrate the result (+).

 

[pseudockb]

Actually it was called delta-sigma when it first appeared because substration comes before summation. However, many people seem to remember the name wrongly and so it becomes sigma-delta.

 

[Robertt]

does delta mean input analog signal substract the reference voltage and then sigma means the sumation in integrator?

 

[sunking]

you can reference the book:
Delta-Sigma Data Converters: Theory, Design, and Simulation

 

[ocarnu]

There is no reference there, that is in pipeline. It is input signal minus quantized voltage.

 

[tatakt]

Hi,
The "delta" refers to the negative feedback (subtraction) and "sigma" refers to the summation (accumulation) in integrator.
Good Luck,
Tata

 

[carlyou]

upstair is right

 

[eezou]

Sigma :+
Delta: -

 

[xerxer]

THis is a book refer to ad sigma-delta converter
Design-of-low-voltage-low-power-sigma-delta-modulators

 

[beckchm]

minus and integrate

 

[bappi48]

Actually it was called delta-sigma when it first appeared because substration comes before summation. However, many people seem to remember the name wrongly and so it becomes sigma-delta.

Please check this: bappi.yolasite.com/blog/sigma-delta-or-delta-sigma-editor-s-notes-from-analog-dialogue-vol-24-2-1990-by-dan-sheingold