Koherenttilähetys

Koherenttilähetys, also known as coherent transmission, is a method of transmitting information using coherent waves. In this technique, the phase of the transmitted signal is synchronized with a reference signal, typically generated by a local oscillator. This synchronization allows the receiver to demodulate the signal more accurately, as it can compare the phase of the received signal with the phase of the reference signal.

Koherenttilähetys is commonly used in various communication systems, including radar, satellite communications, and optical communications. In radar systems, for example, coherent transmission allows for the detection of small objects and the measurement of their distance and velocity. In satellite communications, coherent transmission enables the use of more complex modulation schemes, which can increase the data transmission rate.

The main advantage of koherenttilähetys is its high sensitivity and accuracy. However, it also has some drawbacks. The synchronization of the transmitted and reference signals requires precise control of the phase, which can be challenging in some applications. Additionally, coherent transmission systems are generally more complex and expensive than non-coherent systems.

In optical communications, koherenttilähetys is used to transmit data over long distances with minimal signal degradation. The coherent detection of the received signal allows for the compensation of the phase and amplitude distortions introduced by the optical fiber, which can improve the overall performance of the communication system.