Question

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

• A. $0.1kHz$
• B. $0.5kHz$
• C. $1kHz$
• D. $0.75kHz$
• E. $10kHz$

Answer 1

The correct option is E

$10kHz$

Step 1. Given data:

Resistance is,

$\begin{array}{rcl}R& =& 1k\Omega \\ & =& {10}^3\Omega \end{array}$

Capacitance is,

$\begin{array}{rcl}C& =& 1\mu F\\ & =& {10}^{-6}F\end{array}$

Step 2. Finding the suitable frequency of carrier signal:

For better demodulation, the carrier signal frequency should be,

$\frac{1}{f_c}<<RC$

$\frac{1}{f_c}<<{10}^3\times {10}^{-6}={10}^{-3}$

$f_c>>{10}^{3}Hz=1kHz$

Since $10kHz>1kHz$

The carrier signal with the frequency of $\mathbf{10}\mathit{k}\mathit{H}\mathit{z}\mathbf{}$can be detected by a diode AM detector.

Hence, option E is correct.