Fig. 1. Diagram of 4PAM-FTN atmospheric optical communication system

Fig. 2. Comparison of theoretical BER and simulation BER

Fig. 3. Relationship of BER and SNR

Fig. 4. Relationship of BER and propagation distance

Fig. 5. Relationship of BER and parameter τ(SNR at 35 dB)

Fig. 6. Transmission rate of different τ

Fig. 7. BER performance of different τ