AM Modulation

Create an AM modulation system with GNU Radio as shown in the following diagram:

Note that all signals here use float, and the parameters adjusted for each module are as follows:

• Sample Rate: 200e3
• GUI Range (Signal Freq):
  • ID: fm
  • Label: Signal Freq
  • Default: 2e3
  • Start: 500
  • Stop: 10e3
  • Step: 100
• GUI Range (Index):
  • ID: ka
  • Label: Index
  • Default: 0.5
  • Start: 0
  • Stop: 1.5
  • Step: 0.1
• Signal: Frequency = fm
• Carrier: Frequency = 50e3
• Multiply Const: Constant = ka
• Add Const: Constant = 1

The simulation result is shown in the following diagram:

To facilitate later testing of signal demodulation, we store the modulated signal in a file. Add a File Sink as shown in the following diagram:

The file parameter in the File Sink can be set freely, it is recommended not to include Chinese characters or spaces in the path.

Exercise 3

1. Complete the above simulation.
2. Briefly analyze whether the sampling rate of this simulation system is sufficient.
3. Try to produce three types of AM modulation results with modulation indices of 0.5, 1.0, and 1.5 respectively.