Spectrum inversion in NCDMA to Ensure Compliance with 3GPP2

December 02, 2013 // By Graham Prophet
Maxim Integrated has published a tutorial application note dealing with signal handling in the narrow-band code-division multiple-access (NCDMA) standard.

Unlike many other cellular standards, NCDMA is required by the 3GPP2 standard to perform spectrum inversion in the physical layer before transmission and after reception. With today’s vast selection of radio frequency (RF) transceivers and baseband processors, it is easy to imagine how one could come across a set of RF transceiver and baseband processor that have mismatched spectrum in the transmit and receive paths. This simple oversight will result in noncompliance to the 3GPP2 standard and failure to demodulate. However, there are a few simple techniques that can help determine if spectrum inversion has been performed on a signal. This tutorial presents three techniques that perform spectrum inversion on RF transceivers that do not have built-in spectrum inversion.

Download a pdf of the application note from Maxim Integrated here.