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The description and function of the attenuator
来源: | 作者:hk1996c2 | 发布时间: 2017-08-06 | 3655 次浏览 | 分享到:

The attenuator is a circuit for introducing a predetermined attenuationwithin a specified frequency range. It is generally indicated by the number of decibels that are introduced and the number of ohms of its characteristic impedance. The attenuator is widely used in cable television systems to meet the requirements for multi-port pairing. Such as the input of the amplifier, the control of the output level, the control of the branch attenuation.


There are two types of attenuator, passive attenuator and active attenuator. The active attenuator is combined with other thermistors to form a variable attenuator, which is used in the amplifier for automatic gain or slope control circuit. There are two types of passive attenuator, fixed attenuator and adjustable attenuator.


The attenuator is widely used in electronic equipment.The main purpose is:

1, adjust the size of the signal in the circuit

2, in the comparison method measurement circuit, it can be used to read the attenuation of the measured network.

3, To improve the impedance matching. If some of the circuit requires a relatively stable load impedance, you can insertan attenuator between this circuit and the actual load impedance between the insertion of an attenuator. This can buffer the impedance changes.


Commonly used fixed attenuator are L-type, T-type, bridge T-type, π-type. And L-type is asymmetric attenuator, mainly for impedance matching. T-type, bridge T-type, π-type are symmetrical attenuator, mainly used for attenuation. For the classic three-type attenuator, π-type, T-type, bridge T-type, the attenuation effect is better. But for high-frequency small signal, π or T-type network is more suitable for passive attenuation.So the π-type network is chose to do attenuation.