tokens: Channel filtering shall be obtained by one of the following two methods : - Square - root raised - cosine ( SRRC ) baseband shaping filter located prior to the modulator , with a channel roll - off factor a of 0,35 ( or 0,5 ) as described in 9.2.6.2 . NOTE This waveform shaping is used in association with a linear modulator and power amplifier . - Post - amplifier shaping using an output filter located at the output of the non - linear power amplifier as described in point 9.2.6.3 . NOTE In this case a NRZ - like shaping is used in conjunction with a non - linear 8-phase modulator .