Frequency Modulation
Vary frequency of the signal
- High frequency means 1 (or the opposite)
- Low frequency means 0 (or the opposite)
- In a bit period, keep frequency high to send a 1
- In a bit period, keep frequency low to send a 0
- To send 1101, send High-High-low-High
Radios that use Frequency Modulation: SINCGARS, Civil-Police/Fire