In many modern military systems it is necessary to digitize wideband data of bandwidth up to 10 GHz or more at say 8-bit accuracy for subsequent processing by computer. This is currently beyond the capability of any single current electronic A/D converter, and a variety of alternative techniques have been investigated to alleviate this problem. In the laboratory a digital sampling oscilloscope can digitize signals of bandwidth up to at least 50 GHz, but only through the use of a repetitive input waveform. Our technique involves amplitude-modulating a single radar return on to the output of a laser diode, and using of an assembly of single-mode optical fiber delay lines and couplers to replicate this optical waveform in time, effectively converting it into a repetitive (optical) waveform. This repetitive waveform is converted back to the electrical domain through a photodiode, and sampled with a conventional (relatively) low-speed ADC. The latter operates in a Vernier mode, taking successive samples at different elapsed times in the replicated electrical waveforms, so as to build up a complete record of the waveform. The paper discusses the design of the system and various practical issues, and presents preliminary results on its operation.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.