Signal waveforms sometimes have unwanted lower-level noise voltages. The noise can be removed by a series noise clipping circuit, which simply consists of two inverse-parallel connected diodes, as shown in Fig. When the noise amplitude is much smaller than the diode forward voltage drop (VF), and the signal amplitude is larger than VF, the signals are passed and the noise is blocked. The signal peak output voltage is ( V -VF ). A dead zone of ±VF exists around ground level in the output waveform, indicating that inputs must exceed ±VF to pass to the output. For noise voltage amplitudes that approach ±VF, two diodes may be connected in series to give a larger dead zone.
