Noise measurements. (a) Input-referred baseline current noise spectrum for CF = 0.15 pF, fs = 4 MS s−1. Also shown is the measured open-headstage of an Axopatch 200B in whole-cell mode. (b) Baseline RMS current noise as a function of bandwidth. (c) Baseline current noise traces corresponding to points in b. (d) Measured noise floor of the new amplifier with pore A. A polynomial fit is also shown to Sn(f) = Af −1 + B + Cf + Df 2, where A–D are fitting parameters. (e,f) RMS current noise and traces with a pore present, corresponding to data in d. (g,h) SNR as a function of bandwidth for two nanopores measured with the CNP. For pore A, CM = 6 pF and ΔI = 882 pA (400-bp DNA, 400 mV, n = 430 events). For pore B, CM = 25 pF and ΔI = 840 pA (50-bp DNA, 400 mV, n = 2,974 events). As event durations varied, the SNR is shown for a range of 1 μs < τ < ∞. (i) Maximum achievable bandwidth for SNR > 5 as a function of signal amplitude (ΔI) for Pore A, Pore B, and the CNP baseline (CM = 0).