In this Volume of Electronics Journal we are presenting four papers. First paper in this volume titled “Mobile Digital Storage Oscilloscope” explains advantages of mobile DSO over CRT based CROs along with the block diagram, circuit and system details. It also discusses use of smart mobile phone application which converts it into a Mobile DSO.
Our second paper titled “Operational Amplifiers Part – III Active Filters Part – I” and is continuation of series on OP-AMPs and use and application of OP-AMPs as active filters. It also deals with the advantages of active filters over passive filters mainly the amplification along with the sharper frequency response. Some of the different types of active filters is also included in this paper.
Third paper titled Operational Amplifiers Part – IV Active Filters Part – II. This paper is in continuation of earlier paper and again deals with different types of Active filters, classifying them as Butterworth filter first, second order with different types of frequency responses namely band pass ( wide band pass narrow band pass filters).
Our final paper of this volume is titled Looking Over the Horizon with the “Artificial Ionospheric Mirror” This paper deals with new idea to overcome the limitation of distance of communication in existing Radar systems. As we know that Due to the Earth’s curvature, there are limitations to the distances we can observe standing on the ground. Similarly, the Radar systems for defense also face this limitation. So if we had a mirror high up in the sky that was tilted such that when we look up we might be able to see what is across the horizon? This idea is made possible with a complex system of phased array antennas that radiated high power RF (Radio frequency) high up in the sky and painted the ionosphere with lot of ions. We hope all the papers/articles presented in this volume will be useful to the readers in the field of
Electronics and also to a common person.