ZDO Corporation

Software Consulting since 1998

Thursday, January 1. 2004

Telephony Posted by Onur Cinar in Telephony

Comments (0)
Trackbacks (0)

E-Model

E-Model is a planing tool for estimating the overall quality in a telephone network. It is an ITU-T strandard.

R Factor = Ro - Is - Id - Ie - A

  • Ro: Signal to noise ratio.
  • Is: Impairments simultaneous to voice signal transmission.
  • Id: Impairments delayed after voice signal transmission.
  • Ie: Effects of Equipment (e.g. codecs).
  • A: Advantage factor (account for caller expect).
    • 0 - Wireline
    • 5 - DECT
    • 10 - GSM
    • 20 - Locations only reached by double sattelite hops.

User SatisfactionR-Factor Value RangeMOS*
Very Satisfied

90-100

5

Satisfied

80-89

4

Some Users Dissatisfied

70-79

3

Many Users Dissatisfied

60-69

2

Nearly All Users Dissatisfied

50-59

1

*MOS: Mean Opinion Score ITU-T P.800.

Perceptual Evaluation of Speech Quality (PESQ) is a tool which compares the original and product speech and calculates a MOS score ITU-T P.862.


Trackbacks
Trackback specific URI for this entry

No Trackbacks

Comments
Display comments as (Linear | Threaded)

No comments

Add Comment


To prevent automated Bots from commentspamming, please enter the string you see in the image below in the appropriate input box. Your comment will only be submitted if the strings match. Please ensure that your browser supports and accepts cookies, or your comment cannot be verified correctly.
CAPTCHA
 
 

Frontpage - Top level