Correlation of two-tone 3rd-order Intermodulation Distortion Ratio and EDGE Adjacent Channel Power Ratio at 900MHz

The performance and architecture of the GSM (Global System for Mobile Communications) cellular radio network relies largely upon adjacent channel interference. A given quality of voice and data link can be achieved by keeping the channel interference to minimum. The 3rd Generation Partnership Project (3GPP) recommends the use of the EDGE (Enhanced Data Rate for GSM Evolution) adjacent channel power ratio (ACPR) test parameter to qualify the interference generated by one radio transmit channel into a neighboring radio channel. This paper presents a linear relationship between the EDGE ACPR and the classical two-tone 3
^rd
-order intermodulation distortion (IMD3) test parameters - achieved through the Pearson product-moment correlation coefficient test, using a commercial 900MHz EDGE power amplifier (PA) module as DUT (device-under-test). Both ACPR and IMD3 measurements relate the distortion power outside the useful band (the adjacent channel) to the RF (radio frequency) power inside the useful band (the main channel). Outstanding results permit the use of IMD3 measurement in place of EDGE ACPR testing - with discretion.