Abstract: A communications bus management circuit for a current probe system detects the connection of the current probe system to an instrument and the connection of a current probe to a current probe amplifier of the system. A controller generates a probe enable signal in the presence of the detected connection to the instrument that is coupled to a switching circuit. Switch elements couple the communications bus of the instrument to the communications bus of the current probe amplifier in the presence of the probe enable signal. The controller further generates a current probe present signal in the presence of the detected current probe that is also coupled to the switching element. A further switch element couples the data line of the instrument to ground via a resistive element in the presence of the current probe present signal and floats the data line when the current probe present signal is absent.

Abstract: An electric lighting fixture for mounting relative to a ceiling is disclosed. An enhanced light deflecting louver system is also disclosed in which the louvers provide enhanced light deflection.

Abstract: An apparatus and method for digitizing a repetitive waveform using an analog oscilloscope uses a successive approximation technique. For each sample point on the repetitive waveform a digitizing level is compared with the repetitive waveform at that sample point, and the digitizing level is adjusted until it essentially equals the magnitude of the repetitive waveform at that point. The particular sample point is determined by comparing a delay level with a ramp signal that starts from an initial fixed trigger point on the repetitive waveform. Each point is digitized in this manner in one of three modes. The first mode samples the same point on successive iterations of the waveform until that point is digitized, and then the next point is digitized. The second mode samples each point once per iteration of the waveform by stepping the delay level n times during each iteration, and adjusting the digitizing level individually for each sample point until the digitization is complete.