Cable length and the delay of signal onset. A: detected onset time increases with increase in cable length between detector and oscilloscope. Onset time was recorded 20 times each for 6 lengths of cable. Mean traces of 20 trials shown for each length. Adding cables elsewhere in the system produces this same effect. B: onset time as a function of cable length in system (shading as in A). Means are 0.76 (SD 0.03), 1.1 (SD 0.06), 1.5 (SD 0.09), 1.9 (SD 0.1), 2.4 (SD 0.18), 2.8 (SD 0.21) μs [mean (SD), n = 20]. Overall, mean onset time is 1.8 (SD 0.76) μs.