UHF SATCOM linear-phase constant-amplitude waveform shaping

With the existing UHF satellite frequency plan requiring narrowband channels to have 5-kHz separation and wideband channels to be spaced on 100 kHz centers, narrowband channels require the more stringent adjacent channel interference control. MIL-STD-188-181 and the Joint Chiefs of Staff Memorandum MJCS-33-87 require linear-phase rotation over 50% of the bit period with a constant-amplitude envelope of the carrier for BPSK (binary phase shift keying), to achieve spectral containment for 5 kHz channelization. BPSK and OQPSK spectral emissions are examined in the light of uplink adjacent channel emissions at the satellite receiver, with considerations for platform Doppler, satellite inclination, and reference frequency inaccuracies, to clearly show the need for waveform shaping. The terrestrial receiver penalty for waveform shaping to control adjacent channel emissions has been calculated and measured to be ⩽1 dB and is partially offset by the improvement in packing the signal power within the assigned channel