Modulation

What you will learn

• Software: fairly simple constructs
• Domain: Modulation, FSK, tradeoffs

Amplitude Modulation

• Construct a carrier (high frequency) and a signal, represented as a list of values
• Simply add the two
• Visualize all the three signals
• Take the modulated signal and subtract out the carrier to
  recover the original signal

Frequency Modulation – 1

• Let’s start with a binary data signal.
• Based on the frequency of your carrier, determine
  an appropriate $ Delta_f $
• Modify the carrier frequency for a range of cycles based on
  the input signal
• Plot all three signals
• Recover the input signal

Frequency Modulation – 2

• Rather than a $f_c pm Delta_f$ for a $1$ and $0$, use a return-to-zero scheme. So the frequency changes only if there is a change
  from zero to one or vice-versa.
• Plot all three signals
• Recover the input signal

Frequency Modulation – 3

• You could group your input data by two bits (so four levels) and use correspondingly more $Delta_f$
• Plot all three signals
• Recover the input signal