The Use of a High-Speed 12-Bit A/D Converter for Digital Sampling of Communication Signal Carriers

Abstract

A 12-bit A/D converter having an aperture uncertainty of 25 psec and a maximum sampling rate of 5 MHz was used to experimentally determine the magnitude of the spurious-free dynamic range that could be obtained with present off-the-shelf technology. A larger number of quantization bits would have resulted m unacceptably slow speed and an unacceptably low maximum frequency limitation. A smaller number of bits would have yielded a smaller spurious-free dynamic range. Since we did not have a digital processing facility to analyze the A/D directly, a D/A converter, deglitcher (sample-and-hold), and a high quality spectrum analyzer were used to evaluate the A/D performance. Consequently, the results reported are characteristic of the composite A/D-D/A-deglitcher system rather than the A/D alone. These results, however, are directly applicable to a first generation towed communication buoy system which would probably use the' composite A/D-D/A-deglitcher architecture.