Determine the instantaneous frequency in hertz of each of th

Determine the instantaneous frequency in hertz of each of the following signals: (a) 10 cos (200 pi t + pi/3) (b) 10 cos (20 pi t + pi t^2) (c) cos 200 pi t cos (5 sin 2 pi t) + sin 200 pi t sin (5 sin 2 pi t)

Solution

general equation is Acos(2pie*f*t + phase)

where f is instantaneous frequency .and A is amplitude

a) here 10 is amplitude

200pie*t=2pie*f*t

on solving

f=100 hz

b) here amplitude =10

phase =pie*t^2

20pie*f*t=2pie*f*t

on solving

f=10 hz

c)it is combination of two sinusoidal signal but having same fundamnetal frequency

i.e. 200pie*t=2pie*f*t

on solving

f=100 hz