frekvenssihypyllä

Frekvenssihypyllä, often translated as frequency hopping, is a method of transmitting radio signals by rapidly switching a carrier frequency among many distinct frequencies over a short, determined sequence. This sequence is known to both the transmitter and the receiver. The purpose of frequency hopping is to improve the security of communication and to reduce interference.

By rapidly changing frequencies, a frequency-hopping signal is difficult to intercept or jam. An eavesdropper would need to know the exact hopping sequence to follow the transmission, and a jammer would have to disrupt a wide range of frequencies simultaneously to be effective. This makes it a robust technique for military and secure communication applications.

Frequency hopping is also used to mitigate interference in crowded radio spectrums. If a particular frequency is experiencing interference, the signal quickly moves to another frequency, minimizing the impact of the disruption. This allows multiple users to share the same spectrum more efficiently.

The hopping sequence is typically generated by a pseudo-random number generator, making it appear random to anyone without knowledge of the algorithm and the starting seed. The rate at which the frequency changes is called the hop rate. There are various types of frequency hopping, including slow frequency hopping and fast frequency hopping, distinguished by their hop rate relative to the data rate. The technology is a key component in spread spectrum communication systems.