Electrical characteristics of a cryoelectric memory system

A detailed examination of the characteristic impedance, propagation velocity, dispersion, and losses in a large hybrid-organization cryoelectric memory system is presented. A frequency-domain analysis of the lines in such a system reveals that they behave as band-limited transmission lines having essentially real characteristic impedance and propagation velocity, and therefore negligible dispersion. For the pulse waveforms of interest, the periodic capacitive and inductive loading effects in the multiconductor configuration reduce to effective distributed inductances and capacitances equal to the low-frequency equivalent values. The periodic loading structure dictates only the small-scale details of pulse rise time on the lines. Calculated and experimental results of time-domain analysis support these findings. The only limit to the number of bits driven or sensed along a single line is the desired cycle time; the transmission line network will impose no further electronic limitations on system performance for capacities up to about 10⁸bits.