METHOD AND APPARATUS FOR CHANGING THE TYPE OF MODULATION

摘要

A block edge detector (310) determines whether a wireless communication transmission with a first modulation having excess spectral emissions will be transmitted at a frequency on a block edge. In response, a modulator selector (320) changes the wireless communication transmission to a second modulation with lessened spectral emissions. Preferably, the second modulator (340) is operably coupled to an alternative lookup table (360) wherein phase trajectory entries likely to cause excess spectral emissions such as spurious emissions are smoothed. The entries may be smoothed by filtering, non-linear extrapolation, and/or linear extrapolation. Alternatively, the second modulator (340) uses an alternative lookup table (360) that is a GMSK modulator with BT less than 0.3.