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What Are the Key Parameters of the Attenuator?

Ⅰ. About the attenuator

The attenuator is a circuit used to introduce a predetermined attenuation within a specified frequency range. And it is generally indicated by the decibels of the introduced attenuation and the ohms of its characteristic impedance. Attenuators are widely used in cable television systems to meet multi-port level requirements. Such as amplifier input, output level control, and branch attenuation control. There are two types of attenuators, passive attenuators, and active attenuators. The active attenuator cooperates with other thermal elements to form a variable attenuator, and the device is used in the automatic gain or slope control circuit in the amplifier. Passive attenuators include fixed attenuators and adjustable attenuators.

Ⅱ. The key parameters of the attenuator

1. Attenuation

It is used to describe the amount of signal reduction from one end to the other during transmission. It can be expressed in multiples or decibels of coaxial attenuators.


It is equal to the ratio of the characteristic impedance to the impedance of the load connected to the output of the transmission line.

3. The maximum average power

The maximum power that can be applied to the input of the attenuator for a long time at the specified maximum operating temperature when the output of the attenuator is terminated with a characteristic impedance. When the operating temperature drops to 20ºC and the input power drops to 10mW, the other specifications of the attenuator should not change.

4. The insertion loss power factor

The power factor of insertion loss refers to the change in insertion loss (dB) when the input power is from 10mW to rated power.

5. The maximum peak power

When the output terminal of the rf attenuator is connected to the characteristic impedance, at the specified maximum operating temperature, the maximum peak power of 5ms pulse width is applied to the input terminal of the attenuator within the specified time. When the operating temperature drops to 20ºC and the input power drops to 10mW, the other specifications of the attenuator should not change.

6. The temperature coefficient

It is the maximum change in insertion loss over the maximum operating temperature range, expressed in dB/ºC.

7. The shock and vibration

The RF power attenuator must withstand shock and vibration tests in three directions.

8. The insertion loss frequency response

It refers to Variation in loss value (dB) over a frequency range at 20ºC.

9. The operating temperature upper limit

It is the maximum temperature (ºC) at which the attenuator operates at maximum input power.

10. The deviation from nominal insertion loss

The deviation from the nominal insertion loss refers to the measured insertion loss deviation from nominal Value at 20ºC and input power of 10mW.

11. The connector lifespan

It means the number of normal connections/disconnections; all electrical and mechanical indicators should meet the requirements within the specified life.

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