Extended Data Fig. 2: Output response analysis of the RNPU circuit to input pulses.
From: Analogue speech recognition based on physical computing
a, The RNPU circuit shown in Fig. 2 and Fig. 3 of the manuscript is fed with input pulses staircase-like input signal (orange) and the output (blue) is measured. The measurement sampling rate is set to 25 kS s–1. b, The output response to the first input pulse is shown in blue and the fit to the curve in orange. Based on the fitted curve, the time constant τ is calculated to be 22.3 ms. c, The output response to the second input pulse is shown in blue and the fit to the curve in orange. The time constant is calculated to be 36.7 ms. The change in the time constant, i.e., the RNPU resistance and its internal capacitance, indicates that the charge stored on the capacitance influences the device behaviour in a recurrent form.
