#### Question 5.3 Question 5.4

## BER performance of ASK

We saw in Chapter 3 that the performance of a digital communications system is at the simplest level presented as a probability of bit error, or a probability of symbol error, as a function of the received Eb/N0 ratio. For a binary modulation system, symbol and bit error probability are the same. Binary ASK effectively uses a unipolar baseband modulation source and the performance for matched filter detection has already been derived in Chapter 3. The BER performance for coherent and non-coherent ASK is shown here for an additive white Gaussian noise limited channel. The Eb/N0 value is for the average symbol power, which is 3 dB less than the peak symbol power for ASK (the carrier is off for approximately half of the transmitted symbols). If performance is to be gauged in terms of peak power, then ASK suffers a penalty of 3 dB over the performance shown here. |