pulse density modulation in delta sigma ADC

Hello everyone!
Can anybody suggest me a good paper or book to understand the analog to digital conversion using pulse density modulation in multi-bit ADCs ?
I wanna know how the local average tracks the input...

Pankaj,

The attached file is nice and short Motorola Aplication Note one. I don't know if it will be useful for you. Let me know. Regards. Daniel

Digital Signal Processors Principles of Sigma-Delta Modulation for Analog-to-Digital Converters

by
Sangil Park, Ph. D.
Strategic Applications
Digital Signal Processor Operation