Underwater Acoustic Micromodem for Underwater Internet of Things

Figure 20

Received signals at (a, c) 150 m and (b, d) 300 m. (a) Received FH–8FSK signal, 150 m. (b) Received FH–8FSK signal, 300 m. (c) Received FH–4FSK signal, 150 m. (d) Received FH–4FSK signal, 300 m.

(a)

(b)

(c)

(d)