Designing a GFSK Receiver in Arx

This technical note documents the design of a GFSK receiver i n A x. While GFSK is used in many telecommunication standards, the version described h ere uses toy parameters that are not related to any standard. The code is distributed as free I P on the Bibix website. 1 The note starts by a presentation of the theory and then spends so me attention on how Arx can be combined with testbenches in IT++ 2 and VHDL. The intention is not so much to explain GFSK, but to show how Arx can be used in a larger design. One per forms the design and verification using the C++ generated from Arx, taking advant age of the high simulation speeds attainable in C++. When the design is ready, the correspondin g VHDL is directly available and can be used for synthesis. 1 About Bibix, Arx, and This Document Bibix is a University of Twente spin-off company. Next to offering consu ltancy services, Bibix focuses on the development of Arx, a domain-specific language and tools et f r register-transfer level design. The Arx toolset contains code generators for C++ and VH DL, such that models with identical behavior in both languages can be obtained from a single source code. The Bibix website gives free access to the description of several IP blocks, such as FI R filters, CORDICs and FFTs. This technical note provides some background information on one of the lar g r examples on the website consisting of several IP blocks: a GFSK receiver. The design i a multirate system. Given the fact that the current version of Arx only supports a single clo ck, the system needs to be described by means of multiple Arx files. Testbenches in C++ or VHDL con nect the different blocks into a single top level and provide the appropriate clocks. This document does not explain the Arx syntax and semantics for which the r ead r is referred to the on-line manual available at the Bibix website. 2 Introduction to GFSK Gaussian frequency shift keying (GFSK) is a modulation method for digital communication found in many standards such as Bluetooth, DECT and Wavenis. Digital communication am unts to http://www.bibix.nl http://sourceforge.net/apps/wordpress/itpp/