Digital Communication .  Consider a BPSK system with equally likely waveforms s1(t) = cos(ω0t) and s2(t) = − cos(ω0t). Assume that the received Eb/N0=9.6 dB, giving rise to a bit error probability of 10-5 , when the synchronization is perfect. Consider that carrier recovery with the PLL suffers some fixed error φ associated with the phase estimate, so that the reference signals are expressed as cos(ω0t + φ) and − cos(ω0t + φ). 1. How badly does the bit-error probability degrade when φ = 25 degrees? 2. How large a phase error would cause the bit-error probability to degrade to 10-3?