Elliptical function based differential band pass filter for IF signal processing and EMI applications

This paper presents a design approach for 70MHz elliptical band pass filter for IF signal processing and EMI applications. High roll off and low insertion loss with miniaturized foot print makes the filter suitable for EMI application in harmonic suppression. Extending the concepts of transforming the elliptical function based low pass filter into band pass filter. Parametric analysis is carried out to create a generalized approach for the design of specific band pass filter and fine tuning the response by using PSpice simulator. Low pass zeroes are achieved by optimizing the parallel resonance circuit components of the filter and at the same time pass band transmission is achieved by optimizing the series resonance components. Differential band pass filter conversion from single ended version is presented which is required for performance improvement in IF signal processing requirements for communication links like CDMA & OFDM based systems and direct conversion receivers.