A chirp signal generator without multiplier based on improved CORDIC algorithm

Aiming at the problem of generating chirp signals in harmonic radar design, an improved method based on coordinate rotation digital computer (CORDIC) algorithm is proposed to generate linear frequency modulation signals in field-programmable gate arrays (FPGA). In this method, we propose three optimization options, which are listed a below:(1) Achieve spectrum shifting by splitting the chirp signal into two signal superpositions. (2) reduce the number of iterations of the CORDIC algorithm according to the particularity of the signal. and (3) Use two-stage accumulators to replace the original multipliers. According to the simulation results achieved by Modelsim, the waveform captured by ChipScope and the spectrum information collected by the spectrum analyzer through the antenna in the actual hardware circuit tests, this method can generate better chirp signals with fewer FPGA basic logic units.