Communication Systems Substitution-rearrangement network (SP-network) encryption model Comparison of DSB AM and DSBSC AM modulation in a channel with limited white noise OFDM oversampled signal model 4-FSK modulator and demodulator Transmitter model Translating text into Morse code Evaluation of the characterisation of the ultrashort wave radio channel model Digital communication channel XOR encryption model Gamification DMR protocol physical layer system model Slow motion television BER calculation for QPSK Engee checksum calculation Influence of single BER pulses Declaring model parameters Scrambler BER calculation for 8-PSK Modulation of the main frequency band The permutation cipher model Tone generator QPSK based OFDM communication model Substitution cipher model Modulation analysis BER calculation for BPSK FIR filter generation using command control