Patent ID: 7269229

Claim:
A filtering apparatus in an 8 Phase Shift Keying (8PSK) system, the 8PSK system being utilized for encoding a series of digital bits to output a plurality of corresponding modulation signals, the 8PSK system comprising: a Gray mapping module for mapping a set cf every 3 digital bits into a corresponding first vector by a predetermined mapping process; a 3Π/8 phase shift module for shifting the phase of the first vector from the Gray mapping module to generate a corresponding second vector by a predetermined phase shift process; and a filtering apparatus for filtering the second vector from the 3Π/8 phase shift module to generate one corresponding modulation signal out of the plurality of modulation signals; the filtering apparatus further comprising: a Π/16 phase shift module for further shifting the second vector from the 3Π/8 phase shift module with Π/16 radians to generate a corresponding third vector; a weight distribution module for distributing a plurality of selected weights to a predetermined distribution waveform and for storing a plurality of corresponding weighted distribution waveforms; and a combination module, according to the third vector, for determining which weight distribution waveforms to be selected from the weight distribution module and combining the selected weighted distribution waveforms to generate the modulation signal.