Abstract: High-speed sampling apparatus includes a first source of sampling pulses exhibiting a first sampling frequency and a first sampling circuit coupled to receive an input signal and responsive to the sampling pulses to produce first signal samples. A second source of sampling pulses exhibiting a second sampling frequency is provided; and a second sampling circuit is coupled to the first sampling circuit to receive predetermined ones of the first signal samples and is responsive to the sampling pulses at the second sampling frequency to sample the predetermined first signal samples so as to produce therefrom second signal samples.

Abstract: Current switching apparatus including at least one current switching tree comprised of cascaded sets of switching circuits, with an input set operable with sampling clock pulses supplied at a fixed frequency and the remaining cascaded sets operable at different frequencies, and further including a sample skipping circuit interconnected between successive sets for reducing the effective sampling frequency of the switching tree while maintaining the fixed frequency at which the input set operates. The sample skipping circuit includes a dump circuit selectively energized to dump selected samples produced by the input set. When the apparatus is formed of plural switching trees of different phases, a sampling clock generator having an adjustable delay circuit is used to delay sampling clock pulses by adjustable amounts so as to establish predetermined phases of sampling clock pulses of the same frequency and different phases for use in each switching tree.

Abstract: A test probe having only two substantially rigid electrically conducting members which are insulated from each other, these members terminating in respective contact portions. When the probe is in use, these two contact portions simultaneously contact spaced apart areas of a current conducting segment then being tested. An insulated handle is formed by a protecting layer of insulation coupled to the two conducting members; and a pair of conducting leads pass through the handle and are electrically connected to the respective conducting members. In a preferred embodiment, the two conducting members are constituted by a cylindrical shaft which is longitudinally bisected into separate longitudinal portions that are bonded to each other by a layer of insulating adhesive. The cylindrical shaft terminates in a conical contact tip which also is longitudinally bisected, the two bisected portions of this tip constituting the contact portions of the probe.