Question

$\text{In an Fm system, If both amplitude and frequency of the single-tone message signal are}\text{double, then the bandwidth (according to Carson's rule) of the resultant FM signal will be}$

• A. $\text{Unchanged}$
• B. $\text{Halved}$
• C. $\text{Doubled}$
• D. $\text{Eight-times}$

Answer 1

The correct option is C $\text{Doubled}$

$(BW{)}_{FM}=(1+\beta \left)\right(2f_m)=(1+\frac{A{k}_f}{f_m})(2f_m)\text{Let,}{B}_1=(1+\frac{A_m{k}_f}{f_{m1}})(2f_{m1})\text{Given,}{f}_{m2}=2f_{m1}{A}_{m2}=2A_{m1}\text{Now,}{B}_2=(1+\frac{A_{m2}{k}_f}{f_{m2}})(2f_{m2})=(1+\frac{A_{m1}{k}_f}{f_{m1}})(2\times 2f_{m1})=2B_1$