Question

A diode $AM$ detector with the output circuit consisting of $R = 1 M\Omega$ and $C = 1 \muF$ would be more suitable for detecting a carrier signal of

• A. 0.1 MHz
• B. 0.5 MHz
• C. 1 MHz
• D. 10 MHz

Answer 1

Answer: (D)

Here, $R=1\,M\Omega=10^{6}\,\Omega$
$C=1\,pF=10^{12}\,F$
$\therefore RC=\left(10^{6}\right)\left(10^{-12}\right)=10^{-6}\,s$
For demodulation, $\frac{1}{\upsilon_{c}} < < RC$ or $\upsilon_{c} > > \frac{1}{RC}$
where $υ_{c}$ is the frequency of the carrier signal.
$\therefore \upsilon_{c} > > \frac{1}{10^{6}}=10^{6}\,Hz=1\,MHz$
Thus, it would be more suitable for detecting a carrier signal of $10\, MHz.$