UK-based Psytechnics, a provider of voice-quality measurement systems for telecomm designers, announces an add-on E-Model measurement capability to its family of voice quality products.
This is significant because obtaining voice-quality measurements during the design phase of a product can yield margin by avoiding customer-related issues in the field.
Also, when creating any kind of handsets, whether they be VoIP (voice over Internet Protocol) phones, cellphones, or good ol' PSTN (public switched telephone network) telephones, testing can reveal acoustic and electronic issues that can affect the ability of an instrument to perform satisfactorily.
The same preventative actions can be applied to telecom infrastructure during design. During development phases, an analysis of voice quality of a telecom device can be helpful, whether under actual load conditions or while using different CODECs and/or compression schemes.
That's where the E-model comes in. It's essentially a planning tool for estimating the overall quality in a phone network.
During design, you can the E-model to estimate the likely quality that an end-user will experience. You can gather input information from reference tables, enter it into the E-model, and calculate the estimated Transmission Quality Rating, or R Factor.
However, note that the ITU doesn't recommend that the E-model be used as a valid measurement tool for live networks. Despite this, some companies ignore
ITU guidelines and promote the E-model as a live voice quality measurement product.
"While we would never advocate the E-model to be used for accurate live voice quality measurement," notes Psytechnics CTO Mike Hollier, "there is widespread interest among engineers to compare estimated voice quality with actual values on the same scale. The mean opinion scores (MOSs) from our algorithms are ITU-standard, and therefore are accurate inputs to the E-model."
MOS is a numerical measure of the quality of human speech. It can be thought of as a "customer experience" metric.
Significantly, the E-model source code is freely available to the public from the ITU for academic, business, or personal use, and Psytechnics publishes a white paper on the E-model. It can be downloaded on the company's Web site.
Finally, Psytechnics is making its E-model application available free in January 2004.
For details, contact Iain Wood at Psytechnics ltd., Fraser House, 23 Museum St., Ipswich IP1 1HN, England. E-mail: firstname.lastname@example.org. Phone: +44 (0) 1473 261 838. Visit Psytechnics's Web site for further details, and to download the white paper.