Speech Codecs

0.5 Days / 1 Live Online Sessions (0900-1230) / Technical Level: Level 3

Course Code: IP1403

Course Summary

This course looks at different types of voice coder used in GSM and UMTS networks and then investigates its basic operation looking at CELP and VSELP.

The course progresses to look at the functionality of the AMR voice codec and suggest its benefits and looks at Source Controlled Rate (SCR) operation finishes by looking at lost frame substitution.

Who would benefit

Attendees of this course should require an understanding of the key voice coders used in modern telecommunication networks, as well as their development and operation. This course will be of particular relevance to those interested in the performance of different speech codecs for optimising voice through the network.


Delegates should have experience or an interest in mobile networks otherwise there are no prerequisites for this course.

Topic Areas Include

  • Voice Coding

  • Linear Predictive Coders (LPCs)

  • The GSM Vocoder

  • Vocoder Action

  • RPE

  • Vocoder Output

  • GSM Coder and Decoder

  • Subjective Division of Codec Parameters

  • Categorization

  • The GSM Half-Rate Speech Coder

  • Code Excited Linear Predictor (CELP)

  • GSM Enhanced Full Rate Speech Coder

  • Adaptive Multi-Rate (AMR) Voice Codec

  • General Description

  • Source Controlled Rate (SCR) Operation

  • Lost Frame Substitution