A major step forward for audio quality

For decades the audio quality of the PSTN line has relied on an audio bandwidth of 4 KHz. As this is supported by the whole infrastructure, it is not a trivial task to change. The introduction of the VoIP phone has however raised the bar; now all phones using VoIP should be able to support 8 KHz audio bandwidth.

What is “High Quality Audio”?
For decades the audio quality of the PSTN line has relied on an audio bandwidth of 4 KHz. This is supported by the whole infrastructure and as such not a trivial task to change. The introduction of the VoIP phone has however raised the bar; now all phones using VoIP should be able to support 8 KHz audio bandwidth.
In terms of telephony audio quality this is a major step forward. To the common ear there is a notable difference between the standard PSTN audio quality and the improved quality achieved with a VoIP connection.
The question is however whether this really is high quality audio?
For the telecom industry this is definitely high quality audio. For the entertainment and other audio industries relying on “life-like” and perfect audio performance this is however not sufficient and by no means high quality.
For this particular reason RTX has recently invested in a revised and improved protocol for high quality audio. In this context high quality audio means 16 KHz audio bandwidth, or double that of the mandatory wideband audio codec in CAT-iq.
In the chosen architecture it is also possible to bypass the standard chip codec’s and thereby increase the dynamic audio range for the solution. The number of actual bits for user data transported over the air is 128kbit/s and there is a high level of flexibility due to the fact that the user has full control over how these bits are used.
The demonstrator implemented by RTX is made in the 2.4 GHz frequency spectrum. The reason for this is the world-wide application of this frequency band. It is however also possible to make a similar solution in the DECT or DECT6.0 frequency band. New in the 2.4 GHz solution is also a general improved RF performance whereby the solution is much more resilient to noise in the 2.4 GHz frequency band while at the same time being friendlier to other devices in the same spectrum.
More information about the demo can be requested by contacting RTX at technology@rtx.dk.

Embedded Skype

VNU
“By and large, though, this is one of the best examples of internet telephony we've seen."

The Inquirer
“The INQ anticipated that setting up the whole system to work with Skype would be very tedious. The opposite was true.”