Digital wideband receivers are essential elements used in electronic warfare (EW) applications. Instantaneous Frequency Measurement (IFM) receivers are suitable for use in EW systems due to the ultra-wideband instantaneous radio-frequency (RF) bandwidth, fine-frequency resolution, and moderately high sensitivity and dynamic range. Conventional IFM receivers use analog components such as power dividers, crystal video detectors, and hybrids. This paper presents the architecture and design implementation of a patented “digital IFM receiver” algorithm. The invention is capable of detecting short wave pulse or CW signal of 1.2 GHz bandwidth with 2 MHz error for every 100 nsec. The design was implemented and tested on Delphi's ADC3255 (PMC digitizer with Xilinx Virtex-4 FPGA). The outputs were verified using Xilinx's ChipScope Pro.