What are Narrowband FM and Wideband FM?
A narrow band FM is the FM wave with a small bandwidth. The modulation index β of narrow band FM is small as compared to one radian. Hence, the spectrum of narrowband FM consists of the carrier and upper side band and lower side band.
The narrow band FM can be defined as
For large values of modulation index β, the FM wave ideally contains the carrier and an infinite number of side bands located symmetrically around the carrier. Such as FM wave has infinite bandwidth and hence called as wide band FM. The modulation index of wide band FM is higher than 1. The maximum frequency deviation is 75 KHz and it is used in the broadcasting application such as FM radio and TV. The mathematical expression of wide band FM is represented by
S(t) = AcJ0(β)cos2πfct - AcJ1(β){cos2π(fc - fm)t - cos2π(fc + fm)t} + AcJ2(β){cos2π(fc - 2fm)t - cos2π(fc + 2fm)t} -AcJ3(β){cos2π(fc - 3fm)t - cos2π(fc + 3fm)t} +...
Establish the equivalence between Thevenin’s and Norton’s theorems.
State and explain Biot – Savart law.
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