Improved time-base for waveform parameter estimation

An improved gated oscillator time-base and associated auto-calibration algo rithm for use in a high-accuracy sampling waveform acquisition system are d escribed. The time-base architecture consists of a stable 100 MHz gated osc illator, 24-bit counter chain, and a clock period interpolator. The nominal , uncorrected linearity of the time-base is approximately +/- 30 ps. By usi ng an iterative, sine-fit based algorithm, the linearity has been improved to <5 ps. Details of the performance and major sources of error of the time -base and correction algorithm in an equivalent time sampling system are al so discussed.