Strategy for Designing Digital Filters for Embedded Platforms

Abstract

This research focuses on the use of a methodological strategy for the implementation of digital filters on embedded systems. The purpose of the document is to perform a results analysis for the implementation of a FIR filter on a PSOC 5LP, comparing the proposed strategy with the actual response of the architecture used by the selected platform. In the document it will be shown the block diagram of the proposed solution, configuration parameters, algorithmic structures used, computational tools used to calculate operating parameters and the development of validation tests for the proposed strategy. Keyword-Digital filters, PSOC, FIR, embedded systems. I. INTRODUCTION The growing development of electronic components of small size, has allowed to build high quality electronic prototypes at low cost. In particular, prototypes that incorporate a digital processing system, have the ability to execute tasks recorded in their memory. This characteristic makes them a central controller of certain embedded systems, which gives them a functional advantage over conventional digital circuits, since they adapt to different types of applications with a single processing system [1-3]. The versatility of this type of controller has allowed its manufacture by several manufacturers, among which stand out the family of programmable controllers (PSOC: Programmable System on Chip) developed by Cypress in 2002. The PSOC are integrated circuits of programmable matrix, that is, the peripherals are defined by sets of functions and assigned to any terminal of the integrated circuit [2-3]. The manufacture of PSOC and other digital systems allows the processing of large volumes of information and signals in hardware digitally, although the speed of response in these applications is reduced to the function of the scheduled tasks and the architecture of the controller. The applications in the areas associated to the digital processing of the signals have had great advances, some representative examples are: facial or voice recognition [4-5], the development of intelligent sensors [6], the manufacture of wireless audio transmitters [7], the design of biometric systems [8], among others. One limitation that can occur during the implementation of this type of applications, is the increase in the margin of error between the measured value and the real value, since the signals that reach a controller can change its magnitude with a case of an external client, for example: the environmental conditions. This limitation has been partly solved thanks to the development of filters, which have the function of eliminating the effect caused by the factors [9-10]. In electronics, two types of filters are found, analog and digital. Analog filters are usually built as passive components such as resistors, capacitors and coils. Digital filters are constructed from algorithms that adapt to different processing systems, to improve the result obtained when interpreting a digital signal, for example, to eliminate the noise present in an audio signal reproduced by...