Answer 5.6

The BER for non-coherent ASK is given by:

BER = 0.5 exp(-Eb/N0),

Thus for Eb/N0 = 10 dB or a ratio of 10,

BER = 0.5 exp(-5) = 3.37 x 10-3.

From the BER plot for FSK, an Eb/N0 value of approximately 8 dB is required for this BER performance. From the BER plot for ASK in Section 5.2, we see that the performance of coherent ASK is identical to that for coherent FSK requiring approximately 8 dB Eb/N0 also.