Note: dBm is the absolute power level with 1mw as the reference value, expressed in decibels. Conversion formula:
Level (dBm)= 10lgw
5W → 10lg5000=37dBm
10W→ 10lg 10000 = 40 DBM
20W → 10lg20000=43dBm
It is not difficult to see from the above that every time the power is doubled, the grade value will increase by 3dBm.
2. Gain (dB): that is, magnification, and the unit can be expressed in decibels (dB).
That is: dB= 10lgA(A is the power amplification factor).
3. Insertion loss: When a device or component is connected to the transmission circuit, the increased attenuation is expressed in dB.
4. Selectivity: Measure the gain in the working frequency band and the suppression ability of out-of-band radiation. The bandwidth of -3dB is the bandwidth when the gain drops by 3dB, and so are -40dB and -60dB.
5. Standing wave ratio (return loss): the ratio of antinode voltage to node voltage (VSWR) when standing wave propagates.
6. Third-order intermodulation: If there are two sinusoidal signals Ω1and Ω 2, many intermodulation components will be generated due to nonlinear effects, among which two frequency components Ω1-ω2 and Ω 2-ω 1 are called third-order intermodulation components, and the ratio of its power P3 to the power of signal Ω1or ω2 is called third-order intermodulation coefficient M3.
That is M3 = 10lg P3/P 1 (dBc).
7. Noise figure: generally defined as the ratio of output signal-to-noise ratio to input signal-to-noise ratio, it is actually calculated by converting it into decibels. The unit is decibel.
8. Coupling degree: the power ratio between the coupling port and the input port, in dB.
9. Isolation: the ratio of the power leaked by the local oscillator or signal to other ports to the original power, in dB.
10, antenna gain (dB): refers to the antenna's ability to concentrate the transmission power in the specified direction. Generally, the field strength e in the maximum radiation direction of the antenna is compared with the uniform radiation field strength E0 of the ideal isotropic antenna, and the gain is defined as the multiple of the increase of power density. Ga=E2/ E02
1 1. Antenna pattern: refers to the electromagnetic wave range radiated by the antenna in free space. The width of the pattern generally refers to the width of the main lobe, that is, the angle between two points when it drops by half from the maximum value. Generally speaking, the wider the pattern, the lower the gain; The narrower the pattern, the higher the gain.
12, antenna front-to-back ratio: refers to the ratio of the maximum forward gain to the maximum reverse gain, expressed in decibels.
13. Simplex: Also known as single-frequency simplex system, that is, transmission and reception use the same frequency, so transmission and reception cannot be carried out at the same time, which is called simplex.
14, Duplex: Also known as different frequency duplex system, that is, sending and receiving use two different frequencies, and either party can receive the other party's voice while talking.
Simplex and duplex belong to the working mode of mobile communication.
15. amplifier: a circuit used to amplify signals.
16, filter: (filter) An element or device that suppresses unwanted frequency signals through useful frequency signals.
17. Attenuator: A four-terminal network composed of zero-phase shift and constant attenuation resistance elements, whose characteristic impedance is frequency-independent in a fairly wide frequency band. Its main purpose is to adjust the signal size in the circuit and improve impedance matching.
18. coupler: a device that extracts part of the signal from the main channel. According to the coupling degree, it is divided into 5, 10, 15, 20...db. The high-power coupler (300W) can be used to extract signals from the base station, and its coupling degree can be selected between 30 and 65 dB. The connectors of couplers mostly adopt N-heads.
19. Load: Components/devices, components or devices whose terminals receive electric power at the output port of a circuit (such as an amplifier) or an electrical appliance are collectively called loads. The most basic requirements for the load are impedance matching and the power it can withstand.
20. Circulator: A device that transmits signals in one direction.
2 1. adapter: a device that connects different types of transmission lines together.
22. Feeder: It is a transmission line that transmits high-frequency current.
23. Antenna: (antenna) converts high-frequency current or energy in the form of waveguide into electromagnetic wave and emits it in a specified direction or reduces electromagnetic wave in a certain direction into high-frequency current.