SYNTHESIS AND IMPLEMENTATION OF A POLYNOMIAL NOTCH FILTER ACCORDING TO AN RF PROTOTYPE

Abstract

The use of modern methods of synthesis of electrical circuits makes it possible to create circuits with frequency characteristics of any complexity that do not require restructuring. However, when solving the problem of creating tunable filters, additional requirements arise for the filter and tuning technologies, especially if we are talking about creating systems in the frequency region bordering between frequencies, where implementation in the form of systems with lumped and distributed parameters is inconvenient in both cases. This article is devoted to the synthesis of a stop filter under such conditions. The goal of synthesizing tunable filters is to obtain either a constant absolute or constant relative bandwidth. The first requirement is typical for radio receiving devices, where it is necessary to ensure the minimum permissible bandwidth during tuning, the second – for radio transmitting devices, where minimum losses in the passband and a constant harmonic filtering coefficient are required. A modified method for the synthesis of rejection filters according to operating parameters is described, the synthesis of a specific filter and technological solutions for its implementation, the choice of a method for its electronic restructuring is described.