How Does Linear Predictive Coding (LPC) Reduce Bandwidth in Speech Coding?

  • Thread starter Thread starter jeejou
  • Start date Start date
  • Tags Tags
    Coding Linear
Click For Summary

Discussion Overview

The discussion centers around the mechanisms by which Linear Predictive Coding (LPC) reduces bandwidth in speech coding, particularly in the context of mobile communications systems. Participants seek to understand the specific processes involved in LPC, including its implementation and algorithms like the Levinson-Durbin algorithm.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant asks for clarification on how LPC reduces bandwidth, expressing confusion over the processes involved and the specific version of LPC used, such as VSELP.
  • Another participant suggests that LPC works by predicting future signal values based on past values, allowing for the storage of differences rather than the full signal, thus reducing the required bits for transmission.
  • There is mention of the Levinson-Durbin algorithm as a potential method related to LPC, though its exact role remains unclear among participants.
  • One participant references a webpage but notes that it does not provide the detailed explanation sought regarding LPC's bandwidth reduction mechanisms.

Areas of Agreement / Disagreement

Participants express confusion and seek clarification on the processes involved in LPC, indicating that there is no consensus on the specific mechanisms or algorithms that effectively reduce bandwidth.

Contextual Notes

Participants have not reached a clear understanding of the assumptions or definitions related to LPC and its implementation, leaving several questions about the technical details unresolved.

Who May Find This Useful

This discussion may be useful for individuals interested in speech coding techniques, mobile communications, and the technical aspects of Linear Predictive Coding.

jeejou
Messages
10
Reaction score
0
Hello everyone,

Question : One version of Linear Predictive Coding (LPC) has been adopted as a standard for speech compression in mobile communications systems. How Linear Predictive Coding (LPC) can reduce the bandwidth in this speech coding ?

Can someone please help me with this question. All I can find in the net is "LPC is the process used for reducing the bandwidth in speech coding". I would like to know how the process is undertaken ? Can someone give me pointers/clue/lectures ?

Thank you in advance.
 
Physics news on Phys.org
Wikipedia is (usually) your friend http://www.engineer.tamuk.edu/SPark/chap7.pdf
 
Last edited by a moderator:
Hi there mgb_phys,

I went through the webpage earlier. Unfortunately it does not say how exactly the LPC reduce the bandwidth. I mean the version of the LPC is VSELP, right ? But, what are the processes involved ? Does the Levinson-Durbin algorithm can be matched to answer the question ? Or there is another technique ? I AM CONFUSED! Anyway, THANKS A LOT FOR THE HELP.
 
I'm not an expert but generally fo rthese sort of things.

suppose you have a signal that is say 16bits, but it isn' random - your voice can't suddenly change 86dB in a 1/20,000 second. You can fit a function of what the sound is going to do in the next smll time interval and then store in say 8bits, the difference between the measured sound and the function. Then to play it back just add the 8bit offset to the function. You need a couple of other codes to say when the function has changed.
Since you only need 8bits instead of 16 you have halved the bandwidth.

The details of the coding scheme I don't know.
 

Similar threads

Coding Bootcamps - Can Anyone be a Six-Figure Coder?
  • · Replies 11 ·
Replies
11
Views
4K
How are pseudo ranges obtained?
  • · Replies 15 ·
Replies
15
Views
4K
Java Javascript reading files: how should I have asked?
  • · Replies 4 ·
Replies
4
Views
1K
Python Applying Accelerated Raymarching to Reduce Rendering Time
  • · Replies 0 ·
Replies
0
Views
2K
KarhunenLoeveDecomposition function in Mathematica
  • · Replies 1 ·
Replies
1
Views
1K
How do you handle algorithms (memorize vs. reference)?
  • · Replies 13 ·
Replies
13
Views
4K
Undergrad How to turn model of Schrödinger's Equation 2D?
  • · Replies 6 ·
Replies
6
Views
3K
Requesting suggestions for languages, libraries, and architectures for parallel (and sometimes non parallel) numerical and scientific computations
  • · Replies 8 ·
Replies
8
Views
5K
Studying How Should I Study Quantum Mechanics and Which Math Should I Know?
  • · Replies 7 ·
Replies
7
Views
3K
Fortran Identify explicit shape spec list in the FORTRAN code
  • · Replies 1 ·
Replies
1
Views
2K