The practical limits of data transmission rates on AM (amplitude modulating) and FM (frequency modulating) radio frequencies are primarily determined by several factors, including bandwidth, signal-to-noise ratio, and modulation techniques.
AM Radio: In AM radio, information is encoded by varying the amplitude of the carrier wave. The maximum practical data transmission rate on an AM radio frequency is limited by the available bandwidth. In the case of standard AM radio broadcasting, the audio bandwidth is typically limited to around 5 kHz. This bandwidth limitation restricts the maximum achievable data rate. Additionally, the signal-to-noise ratio also plays a crucial role in determining the achievable data rate. As noise increases, the ability to distinguish between different signal levels decreases, thus limiting the data transmission rate. In practice, AM radio is not designed for high-speed data transmission but rather for broadcasting voice or music content.
FM Radio: FM radio encodes information by varying the frequency of the carrier wave. The maximum data transmission rate on an FM radio frequency is primarily limited by the available bandwidth. FM radio typically uses a wider bandwidth compared to AM, allowing for better audio quality. The maximum audio bandwidth for FM radio is around 15 kHz, which can support higher data rates compared to AM. However, FM radio is primarily designed for audio transmission, and its data transmission capabilities are limited. Practical FM radio transmissions typically have lower data rates compared to modern digital communication systems.
It's worth noting that digital communication systems, such as cellular networks and the internet, have far higher data transmission rates compared to traditional analog radio systems like AM and FM. These digital systems employ advanced modulation techniques, error correction coding, and wider bandwidth allocations to achieve higher data rates, enabling the transmission of voice, video, and data content.