Introduction

With each day, technology keeps on developing in various regions around the world. This is mostly with respect to electronic and radio frequency equipment, which finds a lot of applications in almost all the work sectors. A type of device that is commonly utilized in association with RF equipment is the band reject filter. These filters mainly comprise a low-pass and a high-pass filters that are set along a parallel connection.

 

As the name suggests, this device enables passage of various frequencies, but rejects particular ones. It is also called band elimination filter or notch filter (Circuits Today, Band Stop Filter, 2011). In some technologies, there is a need for passing certain signal frequencies that are denoted with particular upper and lower limits. This depends on the type of components used in the circuit design.

 

Those businesses who want to buy these devices need to know some important details such as applications, cost, types etc. The following points explain few applications of the reject filters.

 

Band Reject Filter Applications

 

  1. The filter is used mainly in public address systems and speaker systems for ensuring good quality audio.
  2. The devices are a crucial part of telephone technology, as they are used as line noise reducers in case of signal transmission.
  3. In DSL and other internet services, it is important to reduce unnecessary interference as much as possible. The band stop filters are utilized for this purpose.
  4. Radio signals are used for a variety of purposes, and are a common communication device. The filters are needed decrease the static on the radio devices, for enabling clear communications.
  5. Guitar amplifiers are devices similar to PA speaker systems. They are used as an output sound source from musical instruments. The band reject filters are used in such amplifiers to reduce a specific humming sound that may occur after the instruments are plugged.
  6. Other than radios, PA’s and amplifiers, the filters are incorporated in many other electronic communication devices to decrease a specific interference range called ‘noise’ in the form of harmonics. In this manner, there are lesser chances for errors to occur in the output. Unwanted harmonics need to be weeded out for clear communications.
  7. In the medical field, machines like the electrocardiogram (ECG) machine incorporates the use of reject filters for hassle free operations.
  8. The reject filters are an important part of image and signal processing units.
  9. Optical communication technologies use optic fibres in order to process light transmissions. In such technologies, distortions in the light pathway may occur. To avoid this, band stop filters are excellent ways of achieving clear light transmission.

 

(Electronics Hub, BAND STOP FILTER, 2015)

 

Apart from band reject filters, a tunable filter is a similar device which allows the user to switch between different frequencies for a variety of electronic processes. Before businesses invest in such devices, they should consider factors such as cost, availability, material quality, company brand, etc.

 

Author Name: Mark Johannson

 

Disclaimer – “The above opinions are purely a reflection of the author’s point of view. They do not reflect the position of Ranatec.”