Continue to Site

# about nature of equation(PM or FM)

Status
Not open for further replies.

#### electronics_kumar

##### Advanced Member level 2
how to differenciate pm and fm

here i have uploaded an equation ...i want know whether it belongs to FM or PM

This as such is a angle modulated signal, by seeing this we cant differentiate FM and PM, but in more general case we can write angle modulated signal as
s(t)=Acos(ωt +m(t)*h(t))

for FM, h(t) = u(t)
PM, h(t) = δ(t)

this belongs to PM, as the phase is varied with cos(200*Pi) with 2 the phase sensitivity.

it is mentioned as a problem in Schuam's sries meant for analog and digital communications..there it is mentioned as "it neither belongs to FM or PM"
i am perplexed...

for more deatailed eloboration see B.P.Lathi modern analog and communication systems.

it says that once the modulated signal is given we cannot differentiate whether it is FM or PM.

thnx

purna!

It seems to be like PM because the term 10^6t is added with a low frequency sinusoid. It seems that the phase is varrying.

Hi electronics_kumar,

What is the modulating signal?
The signal
x(t)=A*cos(wt + phi(t))
can be either PM with a modulating phi(t), or FM with modulating d(phi)/dt (the derivative of phi(t)).
Regards

Z

hirs a lab questions......FMand PM equation are stated there..and how it would be generate...

Status
Not open for further replies.