Typical oscilloscopic records gained in an industrial PD test field are shown in Fig. 4.46. The screenshot displayed in Fig. 4.46 a, b reveal that under practical condition the signal-to-noise ratio can substantially be enhanced if the abovedescribed non-conventional concept is adopted. In this context, it should be mentioned that the above-described concept was also beneficial employed for a hand-held, battery-powered PD probe to enhance the signal-to-noise ratio required for PD diagnostics of HV apparatus under on-site condition (Lemke 1985, 1988,1991)