When the modulating frequency is doubled, the | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) In $Frequency 	ext{ } Modulation$ $(FM)$, the modulation index $\beta$ is defined as $\beta = \frac{\Delta f}{f_m}$, where $\Delta f$ is the freq

Vedclass · Accepted Answer

Frequency modulation

Vedclass · Answer

(C) In $Frequency 	ext{ } Modulation$ $(FM)$, the modulation index $\beta$ is defined as $\beta = \frac{\Delta f}{f_m}$, where $\Delta f$ is the frequency deviation and $f_m$ is the modulating frequency.Also, the frequency deviation $\Delta f$ is directly proportional to the modulating voltage $V_m$, i.e., $\Delta f = k_f V_m$.Thus, $\beta = \frac{k_f V_m}{f_m}$.Given that the modulating voltage $V_m$ remains constant, we have $\beta \propto \frac{1}{f_m}$.If the modulating frequency $f_m$ is doubled $(f_m' = 2f_m)$, the new modulation index $\beta'$ becomes $\beta' = \frac{k_f V_m}{2f_m} = \frac{\beta}{2}$.This matches the condition given in the question, where the modulation index is halved when the frequency is doubled. Therefore, the system is $Frequency 	ext{ } Modulation$.

When the modulating frequency is doubled, the modulation index is halved and the modulating voltage remains constant, the modulation system is

Similar Questions

The characteristic impedance of a coaxial cable is typically in the range of ..........

$A$ signal $A \cos \omega t$ is transmitted using $v_0 \sin \omega_0 t$ as a carrier wave. The correct amplitude modulated $(AM)$ signal is:

The process of retrieval of information from the carrier wave is known as:

For $100\%$ modulation $(AM)$,the useful part of the total power radiated is

$A$ modulated signal $C_m(t)$ has the form $C_m(t) = 30 \sin(300\pi t) + 10 \cos(200\pi t) - 10 \cos(400\pi t)$. The carrier frequency $f_c$,the modulating frequency $f_m$,and the modulation index $\mu$ are respectively given by:

Vedclass Test Series

Exam Paper Generator

Online Exam Module