Non-contact test probe.

摘要

The invention is a capacitively coupled probe (102) which can be used for non-contact acquisition of both analog and digital signals. The probe (102) includes a shielded probe tip (104), a probe body (108) which is mechanically coupled to the probe tip (104), and an amplifier circuit (106) disposed within the probe body (108). The amplifier circuit (106) receives a capacitively sensed signal from the probe tip (104) and produces an amplified signal in response thereto. The amplifier (106) has a large bandwidth to accommodate high-frequency digital signals. Further, the amplifier (106) has a very low input capacitance and a high input resistance to reduce signal attenuation and loading of the circuit being probed. The amplifier circuit (106) is disposed in the probe body (108) closely adjacent to the probe tip (104) in order to reduce stray and distributed capacitances. A reconstruction circuit (110) reconstructs digital signals from the amplified capacitively sensed signal. <IMAGE>