Experiment 2 AM Modulation and Demodulation
Experiment 2 AM Modulation and Demodulation
Experiment 2 AM Modulation and Demodulation
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Amplitude (V Pk-Pk )<br />
Frequency (kHz)<br />
4. Connect ch2 to TP4, observe <strong>and</strong> record the carrier signal. What are the<br />
amplitude <strong>and</strong> frequency of the carrier<br />
Amplitude (V Pk-Pk )<br />
Frequency (kHz)<br />
5. Turn the carrier suppress knob fully clockwise ( <strong>AM</strong> setting ).<br />
6. Connect ch2 to TP8 to observe the o/p of the LM1496. Use the message signal<br />
on ch1 (TP2) as the trigger source. Make sure there is no overmodulation.<br />
Record both signals on the same graph.<br />
7. Calculate the modulation index.<br />
8.<br />
<strong>Modulation</strong> Index (m)<br />
Switch the oscilloscope to XY mode. Record the trapezoidal pattern. Find the<br />
modulation index from the trapezoidal pattern, <strong>and</strong> compare it with step 7. Is<br />
there distortion in the modulation process<br />
<strong>Modulation</strong> Index (m)<br />
………………………………………………………………………………………<br />
………………………………………………………………………………………<br />
………………………………………………………………………………………<br />
9. Use the trapezoidal pattern <strong>and</strong> change the modulation level to get 100%<br />
modulation.<br />
10. Remove the oscilloscope XY mode <strong>and</strong> record the resulting <strong>AM</strong> waveform.<br />
6
Change language