Dynamic converter characterization for radar

New surveillance radars require analog-to-digital (A/D) converters that are linear over a large dynamic range for wide instantaneous bandwidth signals. Nonlinearities of the converter cause mainbeam clutter to spread into the clear Doppler region, because of cross modulation and intermodulation between the large clutter and jamming signal components. The present test methods for converters, which are based on sine waves are not adequate because it is difficult to correlate the test results with real-world performance. This paper presents a new test method that employs simulated radar signals to clearly quantify the impact of the A/D converter upon the radar performance under typical operating conditions. This paper describes the new method and the test facility. It also presents results for a 12-bit A/D converter based on the simulated radar signals and compares it with dynamic tests based on sinusoidal testing. The results clearly show that compared to sine wave testing, this method provides more realistic system performance.<
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