9360224 Bradley HYPRES has demonstrated a 6-bit A/D capable of about 5 bits of resolution at 4GHz input bandwidth and about 4 bits of resolution at 7GHz input bandwidth. The input bandwidth is about 10GHz (the 3db point). However, the resolution at GHz frequencies has been limited by dynamic distortion in the thresholds proportional to the input signal slew rate. A new comparator design has been simulated in which these distortions are largely cancelled by symmetry. Simulations indicate an order of magnitude improvement in the aperture time of the A/D if the proper architecture is used (about 3 more bits of resolution at high frequencies). In Phase I, HYPRES intends to fabricate and test this design of verify this level of performance at the single comparator level. Phase II would cover design, fabrication and testing of the full 8-bit A/D. ***
