A TUNABLE COMPLEX BANDPASS FILTER WITH SWITCHABLE CAPACITORS

Разработан метод расчета комплексных фильтров на переключаемых конденсаторах (ПК) по аналоговым про- тотипам. Для этого использован метод преобразования активного комплексного RC-фильтра путем замены резисторов на ПК. Рассмотрен вариант применения идентичных комплексных звеньев на инвертирующих интеграторах, позволяющий осуществлять перестройку параметров комплексного полосового фильтра (КПФ) c помощью синхронного изменения параметров идентичных комплексных звеньев. Представлена принципиальная схема КПФ с НЧ прототипом Баттерворта 2-го порядка на переключаемых конденсаторах. The article is devoted to the development of a method for calculating complex filters on switchable capacitors based on analog prototypes. It is proposed the method of converting an active complex RC filter by replacing resistors with switchable capacitors. It is considered the application of identical complex links with inverting integrators, which allow the tuning of parameters of a complex bandpass filter by the synchronous change of parameters of identical complex links. As an example, a schematic diagram of a complex bandpass filter with 2nd order Butterworth low-frequency prototype with switchable capacitors is developed.

Conception of a Secure Remote Maintenance Procedure Using Dedicated Hardware

Remote control and remote servicing are often very problematic due to restrictive policies in health care and other critical environments. This paper describes our new design of a Secure Remote Service Box, which is a tiny box that offers restricted access and robust security policies for critical environments and institutions. It allows secure remote access (for example, Team Viewer, ...) for remote control and remote servicing and blocks all other Internet traffic and connections. All devices connected to the LAN port are secured by NAT and complex filters that are natively detected and imported by Windows Network Management. The Secure Remote Service Box fulfills Cybersecurity policies for critical environments and institutions and is, of course very reliable and secure by design.

The Inclusion of Socially Irresponsible Companies in Sustainable Stock Indices

Social rating agencies implement complex filters to identify the companies with the best sustainable and social performance and help investors select the companies for their sustainable portfolios. This study analysed whether companies that are defined as ethical, sustainable and socially responsible by those agencies actually deserve this label. More specifically, the inclusion in the prestigious Dow Jones Sustainability Index (DJSI) World of companies that have been involved in controversies according to the Thomson Reuters Eikon database was studied. The results show that the inclusion of irresponsible companies in the DJSI Index is a fact. This outcome is in line with previous studies that criticise the methodologies applied by social rating agencies and those which outline the similarity of sustainable and conventional portfolios. The results may explain the contradictory conclusions regarding the performance of sustainable and conventional mutual funds in numerous studies.