REPUBLIC OF SERBIA

MINISTRY OF DEFENCE

www.mod.gov.rs

MINISTRY OF DEFENCE

Material Resources Sector

Defensive Technologies Department

Military Technical Institute

www.vti.mod.gov.rs

practical Implementation of DIGITAl down conversion FOR wideband direction finder ON FPGA

vuk obradović

UNO-LUX NS d.o.o, vuk.obrad.91@gmail.com

Predrag okiljević

Military Technical Institute, Belgrade, predrag.okiljevic@mod.gov.rs

nadica Kozić

Military Technical Institute, Belgrade, nadica.kozic@gmail.com

DEJAN ivković

Military Technical Institute, Belgrade, dejan.ivkovic@vti.vs.rs

Abstract: Modern direction finders are designed as sensors for interception of radio signals in wider instantaneous bandwidth. Software radio technology offers ability to develop wideband direction finder architectures with programmable intermediate frequency, instantaneous bandwidth and frequency resolution. In this paper implementation of synchronous digital down conversions (DDCs) for wideband direction finder on FPGA is presented. DDCs are used to downconvert signal from intermediate frequency (IF) to baseband. For wider bandwidth DDCs need to be implemented on FPGA which combines the flexibility of a general-purpose DSP plus the speed, density, and low cost of an application-specific integrated circuit (ASIC) implementation. Measurements and computation of input signals from five channels in parallel on two FPGA devices is presented. Benefits of high speed parallel computing have been observed and discussed in this work. System performance and measured results are briefly presented in paper.

Keywords: FPGA, DDC, direction finder, RF, parallel computing