Digital Instantaneous Frequency Measurement Receiver Based On FPGA

Frequency measurement is a very important technique in electronic counter measures(ECM).It is widely used in electronic reconnaissance systems.In this paper the frequency measurement technique is discussed,and a design of a digital instantaneous frequency measurement(IFM)receiver is given.An IFM receiver has many attractive features necessary for ECM applications,such as small size,light weight,wide instantaneous bandwidth,and fine frequency resolution.The IFM receiver is highly susceptible to erroneously reporting frequency if two or more signals are overlapped in time.In this paper,an wideband,fast,fine resolution and compact digital instantaneous frequency measurement(DIFM)is proposed.The algorithm is implemented on the platform of Virtex-5 Field Programmable Grid Array(FPGA)from Xilinx.Due to only one high speed comparator with some relative circuits are needed,this DIFM can be blended in other digital system with compact size.The Rocket IO GTP has been successfully introduced in this system for the interface with comparator.Thanks to the advantage of 1.46 GHz wide-band,the large numbers of RF channels required in traditional solutions can be decreased.Comparing to traditional analog and digital method,this design is more flexible to reconfigure,easy to adjust,and with smaller size.The measurement results show that our invention is capable of detecting short wave pulse and continuous wave(CW)signal from DC to 1.46 GHz with a major error within 3 MHz in less than 200 ns throughput time.This digital instantaneous frequency measurement(DIFM)system has been successfully used in radar systems.And demux can be introduced into IFM receiver for the wider bandwidth use due to the speed of the Virtex-5 Rocket IO.