Frequency modulation and variable-slope delta modulation in SCPC satellite transmission

Subjective assessments are presented of the performance expected with FM, companded FM, and variable-slope DM (delta modulation) in SCPC (single-channel-per-carrier) service to small earth stations. Signal loading for SCPC/FM channels, FM channel scaling, improvements via emphasis/de-emphasis, advantages of a syllabic compander, and effects introduced by a compressor are dealt with. SCPC/FM channel performance and SCPC/DM performance are discussed, with attention given to quantizing error, digital transmission, error-rate induced noise, and equivalent DM noise performance. Peaked intermodulation distributions, voice activation, miss, and false alarm are also covered.