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In the field of wireless communication, there are some specialized terms for the functions and parameters of the wireless module, such as radio frequency power, wireless power gain, standing wave ratio, and receiver sensitivity. Here is a brief introduction:
Radio frequency power generally refers to the arithmetic mean of the power output of a signal in a specific radio frequency cycle to the load in a researched frequency in a radio station, instrument radio frequency stage, and antenna system, referred to as power. It is divided into peak power, average power, carrier power, etc. and is usually represented by P. The linear units of power usually have W, mW, and μW, and the corresponding voltage units are dBW, dBmW (referred to as dBm), and dBμW.
Conversion relationship between radio frequency power voltage units dBW, dBm, dBmV, and dBμV:
When it is necessary to represent a power (or voltage) in the system, the level can be used. The level at a certain point in the system refers to the decibel ratio of the power (or voltage) at that point to a certain reference power (or voltage): 10 lg( P / P0 ) = 20 lg( U / U0 ).
If 1mW is taken as the reference power, the level corresponding to the power P is 10lg(P/1mW), and the unit is expressed as dBmW (decibel milliwatt). For example, when the power is 1W, the level is 30dBm; when the power is 1mW, the level is 0dBm;
The power gain of the antenna in a certain direction (the power radiated by the antenna per unit solid angle) divided by the net power obtained by the antenna from its signal source is called the antenna power gain in that direction, abbreviated as antenna gain.
The maximum value of antenna gain is called the peak power gain of the antenna. Usually, the antenna gain referred to means the peak power gain of the antenna, and the non-peak power gain is often specified as the gain in a certain direction.
The standing wave ratio reflects the matching of the feeder system. It is measured by the ratio of the energy emitted and reflected back when the antenna is used as a transmitting antenna. The standing wave ratio is determined by the impedance of the feeder system. When the impedance of the antenna and feeder are consistent with the impedance of the receiver, the standing wave ratio is low. The feeder system with high standing wave ratio has large signal loss in the feeder.
Receiver sensitivity refers to the minimum received power measured at the user terminal antenna port, ensuring that the bit error rate (BER) does not exceed a certain specific value. The unit of receiver sensitivity is similar to the radio frequency transmitting power and has two representation methods. The commonly used one is to express it in dBm voltage unit.
