All current commercial test systems are limited to data and clock rates of less than 200 MHz. However, many devices being built today operate at data rates greater than 1 GHz (1000 MHz).The inability to make high -speed tests stems from the many problems of measuring a device's high -speed input and output waveforms electrically.The electrical measurement methods used in the current test systems can no longer meet time accuracy and waveform fidelity requirements and are unlikely to do so in the foreseeable future. The problems associated with high -speed measurement include high pin capacitance, long device pin to receiver distances, limited receiver bandwidths, and situating numerous complex electronic assemblies within a small radius of the device.Many of these difficulties can be substantially reduced or eliminated using an electro -optic means of sensing the high -speed test waveforms.The advantages of extracting high -speed device voltage information using electro -optic techniques include non -invasiveness (low capacitance) and very high bandwidth (greater than 10 GHz). Current work in this field is reviewed showing that although electro -optic test techniques have been demonstrated to work well into the hundreds of gigahertz, the techniques are not as yet suitable for the production testing of high -speed integrated circuits.

We present a comprehensive description of an inexpensive bridge circuit suitable for use with low temperature resistance thermometers. The bridge is energized by a pulse source with a duty cycle of 8.33X10-o. Average power dissipation of 10-8 W in the resistance thermometer is achieved by means pf the pulsed operation. An oscilloscope is used as a detector. The "range gate" effect of the oscilloscope serves as an effective noise filter. A precision of four significant figures is obtained with this system.

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