Experiment on Demodulation of an Amplitude Modulated Signal.

 

Experiment Name: Demodulation of an Amplitude Modulated Signal.

 

Required Apparatus:

        I.            Power Supply

      II.            20 MHz Oscilloscope

    III.            Connectors

    IV.            Amplitude Modulation Transmitter KIT (ACL 01)

·         Balanced Modulator -1

Carrier Input: 1-1000 KHz; Modulating Input: 0.1-1500 KHz

·         Function Generator [Frequency: 0.1-100 Hz]

·         Voltage Controlled Oscillator [Frequency: 500-1500 KHz]

      V.            Amplitude Demodulation Receiver KIT (ACL 02)

·         Local oscillator [Frequency: 900-2.1 MHz]

·         Frequency Converter [Output Frequency: 455 KHz]

    VI.            9F Amplifier [Central Frequency: 455 KHz; Gain: 32dB]

  VII.            Envelop Detector

 

Block Diagram:

Figure: AM Demodulation Circuit

Input/Output Waveshape:

 

Figure 01: Waveform of input message signal

 

 

Figure 02: Waveform of modulated signal in output

 

Figure 03: The Comparison between input signal and demodulated signal

 

 

Figure 04: The Comparison between input signal and demodulated signal (phase shifted 90 degree)

Discussion:

From this experiment, we observed the process of demodulation of an amplitude modulated signal. We also know about the function of mixer. We also see that how envelop detector works and how it helps to demodulate a signal.

 

Conclusion:

While doing the experiment, some precautions should be taken. Sometimes we can’t get the accurate wave shape because of the loose connection. So, we have to check the connection properly to get the accurate or proper wave shape.