Question

The name minimum phase shift keying implies minimum _________

(a) Frequency separation

(b) Amplitude separation

(c) Phase change

(d) Amplitude deviation

I had been asked this question by my school teacher while I was bunking the class.

This interesting question is from Constant Envelope Modulation topic in division Modulation Techniques for Mobile Radio of Wireless/Mobile

Answer 1

Right answer is (a) Frequency separation

To explain I would say: The name minimum phase shift keying implies minimum frequency separation, i.e. the bandwidth that allows orthogonal detection. A modulation index of 0.5 corresponds to the minimum frequency spacing that allows two FSK signals to be coherently orthogonal.