| 摘要 |
A system and method for demodulating digital information from a modulated signal that can be represented in a signal space diagram as an odd constellation of sample points. The system comprises filtering means for receiving the modulated signal that includes means for rotating the received sample points 45 DEG clockwise on the signal space diagram such that decision or neighborhood regions can be drawn having borders that are either parallel or perpendicular to the axes of the signal space diagram. As a result, a slicer can easily extract the symbol information from the rotated sample points with a minimum of computational complexity. Moreover, and perhaps most importantly, the rotation is accomplished through a one time modification of the tap coefficients used by the filtering means thus eliminating any additional processor real time required to perform the rotation. Indeed, through this modification of the filtering means, the present invention can be used to effectively and efficiently demodulate odd constellations without any dependence on the baud rate.
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