| 摘要 |
A waveform sampler, for cooperation with a conventional sampling oscilloscope, has, as part of a bridge circuit, two Gallium Arsenide photoconductors mounted on a 50 ohm stripline. One GaAs photoconductor, the sampling photoconductor, is illuminated. The other GaAs photoconductor remains dark and functions as a common mode compensating photoconductor. To sample an unknown electrical waveform traversing the stripline the electrical wave is optically strobed by illuminating the sampling GaAs photoconductor with pulses of light from a laser. To sample an unknown optical waveform the optical wave is focused on the sampling GaAs photoconductor and an electrical strobe signal is sent through the stripline. Outputs from each of the photoconductors are amplified in high input impedance FET amplifiers and after electrical compensation they are passed to a conventional difference amplifier. The difference output is further amplified and fed to a conventional sampling oscilloscope. The sampling oscilloscope provides a conventional DC feedback control voltage to stabilize the bridge circuit and a strobe synchronization pulse for controlling either the electrical or optical strobe. A trigger pulse that is in advance of the signal being sampled is derived from the unknown signal and supplied to the sampling oscilloscope.
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