Fig. 4

Test results for pulse sequences with time-varying intensity and with time-varying frequency. a Comparison between the theoretical intensity and measured intensity for a pulse sequence with time-varying intensity 0.3–3.0 V, pulse frequency 400 Hz and duration 5 s. b Comparison between the theoretical frequency and measured frequency for a pulse sequence with time-varying frequency 400–100 Hz, intensity 3 V and duration 5 s