Digital Communication System – Comparison
DIGITAL COMMUNICATION SYSTEM – COMPARISON (ASK- FSK- PSK- QAM):
| S.No | Parameter | PSK | DPSK | QPSK | QAM | FSK | ASK |
| 1 | Modulation of | Phase | Phase | Phase | Amplitude and Phase | Frequency | Amplitude |
| 2 | Equation of transmitted signal | s(t)=b(t) √2Ps (cos 2∏f0t) | s(t)=b(t) √2Ps (cos 2∏f0t) | s(t)=b(t) √2Ps (cos 2∏f0t+(2m+1) ∏ / 4 m=0,1,2,3 | s(t)= k1√0.2Ps (cos 2∏f0t) + k2√0.2Ps (sin 2∏f0t) | s(t)= √2Ps [cos 2 (∏f0+d(t)Ω)t f-frequency shift | s(t)= √2Ps (cos 2∏f0t) for symbol ’1’=0 for symbol ‘0’ |
| 3 | Bits per symbol | One | One | Two | N | One | One |
| 4 | Number of possible symbols M= 2N | Two | Two | Four | M= 2N | Two | Two |
| 5 | Detection method | Coherent | Non-Coherent | Coherent | Coherent | Non-Coherent | Coherent |
| 6 | Minimum Euclidean distance | 2√Eb | 2√Eb | √0.4Es for M=16 | √2Eb | √Eb | |
| 7 | Minimum Bandwidth(BW) | 2fb | fb | fb | 2fb/N | 4fb | 2fb |
| 8 | Symbol duration(Ts) | Tb | 2Tb | 2Tb | NTb | Tb | Tb |
