# Can the mobile phone signal amplifier be used to amplify the signal in both directions?

Everyone already knows what a mobile phone signal amplifier is, but about the principle of the signal amplifier, some netizens recently said to me: "I really don't understand, how does the signal amplifier achieve two-way amplification"? In response to this question, I will give you popular science today, and remember it in a small book!

## 1. What does two-way mean?

Two-way literally means that both parties in communication can send messages to each other. In terms of communication, two-way communication is also called half-duplex communication, that is, both parties in communication can send information, but not both parties can send messages at the same time (of course, they cannot receive at the same time) . This communication method is that one party sends and the other receives, and then vice versa after a period of time.

Two-way simultaneous communication, also known as full-duplex communication, means that both parties in communication can send and receive information at the same time. One-way communication only needs one channel, so only one party can send and receive a message before the other party can start sending information. However, two-way alternate communication or two-way simultaneous communication requires two channels, one in each direction, and two-way communication has the highest efficiency.

## 2. How does the signal amplifier realize two-way amplification?

1. The mobile phone signal amplifier (professional name: repeater) consists of an antenna, radio frequency duplexer, low-noise amplifier, mixer, ESC attenuator, filter, power amplifier and other components or modules to form an upstream and downstream amplification chain road;

2. The working principle of the mobile phone signal amplifier is: use the forward antenna (donor antenna) to receive the downlink signal of the base station into the repeater, and amplify the useful signal through the low-noise amplifier, suppress the noise signal in the signal, and improve the signal-to-noise ratio ( S/N); then down-converted to an intermediate frequency signal, filtered by a filter, and amplified by the intermediate frequency;

3. The frequency is shifted and upconverted to radio frequency, amplified by the power amplifier, and transmitted from the backward antenna (retransmission antenna) to the mobile station; at the same time, the backward antenna is used to receive the mobile station's uplink signal, and the reverse path is processed by the uplink amplification link : It is transmitted to the base station after the low noise amplifier, down converter, filter, intermediate amplifier, up converter, and power amplifier, so as to achieve the two-way communication between the base station and the mobile station.

When installing a signal amplifier, you need to pay attention: the signal from the indoor antenna cannot be received by the outdoor antenna, otherwise it will cause self-excitation. Generally, the two antennas are separated by more than 8 meters to avoid self-excitation. Now you know how the signal amplifier achieves two-way Have you communicated yet? Come and comment and let me know.