AM and FM are two fundamental ways to encode information onto a radio wave. Understanding the difference helps engineers choose the right modulation for IoT devices, sensors, and long-range wireless links.
Good news: Texas Instruments' CC1120 transceiver (used in Coral RF modules) supports both AM and FM — giving you flexibility without changing hardware.
How They Work
AM (Amplitude Modulation): Varies the strength (amplitude) of the carrier wave. Frequency stays constant. Simple but susceptible to noise.
FM (Frequency Modulation): Varies the frequency of the carrier wave. Amplitude stays constant. Much better noise immunity.
Note: FM is frequency modulation, not frequency hopping. The CC1120 does not support carrier aggregation (CAR).
Key Differences at a Glance
Digital Versions: OOK vs FSK
For AM: On-Off Keying (OOK) — the carrier is turned on/off to send 1s and 0s. Very simple, low cost, but less robust.
For FM: Frequency Shift Keying (FSK) or GFSK — two different frequencies represent 1 and 0. Reliable and noise-resistant.
The CC1120 supports both OOK and 2/4-FSK, making it suitable for a wide range of applications.
Coral RF CC1120 Module Examples
N516AS-B: +27 dBm, 10+ km range, uses narrowband (FSK and OOK).
N519AS: +37 dBm (5W), 16 km range, ideal for extreme long distance.
N511AS-B: Compact +15 dBm module, supports both FSK and OOK.
All these modules leverage the CC1120's flexibility to deliver robust performance in real-world deployments.
Which One Should You Choose?
Choose AM (OOK) when: You need a very simple, low-cost link in a clean environment, and real-time data transmission or you're replacing a legacy OOK device.
Choose narrowband FM (FSK/GFSK) when: You need long range, noise immunity, and reliable data transfer — this fits >90% of industrial IoT applications.
Summary
AM changes amplitude; FM changes frequency. AM is simpler and longer-range but noise-prone. FM is more robust and cleaner at the cost of some bandwidth. The CC1120 gives you both options in one chip — and Coral RF offers ready-to-use modules for either approach.
Browse Coral RF CC1120 modules →
For datasheets or custom design support, contact Coral RF directly.
