Question

Signal and its Hilbert transform have  ________

(a) same energy density spectrum

(b) same power

(c) a phase difference of 60°

(d) a phase difference of 120°

I got this question in an internship interview.

The query is from Coherent Detection of DSBSC Waves topic in portion Double Sideband Suppressed Carrier Modulation of Analog Communications

Answer 1

Right option is (a) same energy density spectrum

Best explanation: Properties of Hilbert transform states that the signal and its Hilbert transform :

i) have same energy density spectrum

ii) are mutually orthogonal

iii) have same auto correlation function

iv) have same magnitude

v) have a phase difference of “-90” degree.