What is a digital step attenuator?
All radio or microwave equipment need to control the power level of the transmitted or received RF signal due to one or all of the following reasons:
- Secure compliance with standards and regulations – and to avoid unhealthy radiation
- Avoid hardware damages due to excessive RF power levels
- Optimize performance of networks, receivers, transmitters, and other RF functions
To ensure that the equipment adheres to them, a digital step attenuator is often a necessity. An RF digital attenuator is a device that is used to apply a controlled amount of attenuation to an RF signal via digital control. There is a wide range of applications for a digital RF attenuator solution including:
- Within any device used for wireless communication, there is a need to adequately control the RF signal levels at various points in the design
- For larger systems and solutions, the overall efficiency is dependent on adequate balancing and control of the RF power levels
- Throughout the product life-cycle of any radio or microwave equipment, there is a need for extensive RF testing. This testing typically includes set-ups where the RF power levels can be controlled by means of digital RF attenuators.
Implementation levels for digital attenuators
It is important to distinguish between three different implementation levels of digital attenuators:
- Integrated circuits or IP-blocks, for tight integration into high-volume products. Requires detailed hardware and software integration
- Digital attenuator modules, requiring less engineering effort, and for integration at the system level
- Stand-alone digital step attenuator solutions, typically including multiple, independent channels and covering a wide range of applications
Specifications of digital RF attenuators
Regardless of application or implementation, a digital RF attenuator is characterized by a specific set of parameters including:
- Operating frequency range
- Minimum attenuation
- Maximum attenuation
- Attenuation step-size
- Attenuation accuracy
Different applications and RF equipment require different parameters and selection of control interfaces. Typically, a stand-alone digital RF step attenuator intended for more general use often has the widest frequency and attenuation range and provides the best accuracy.
What digital step attenuator do you need?
To be able to select the right digital step attenuator for your needs, you first need to understand the application and the preferred implementation (integrated, module or stand-alone). For example, a digital RF step attenuator that’s intended for efficient, automated production testing if mobile devices would require a multi-channel stand-alone step attenuator with a wide frequency and dynamic range as well as high attenuation accuracy.
If you’re unsure what the requirements and specifications of your equipment are, we’d recommend contacting suppliers offering the digital step attenuators. They’ll help you find what type of attenuator your equipment needs to function properly and effectively.