Abstract: An improved sampling network analyzer is described, in which a stored memory, for example, a programmable read-only memory (PROM), is utilized to store the discrepancies between various predetermined mid-band voltage gains and their desired, exact values, and to supply this correction information to the sampling network analyzer in order to produce a more accurate amplitude measure of the amplitude of voltages applied to the inputs of the sampling network analyzer. In addition, low- and high-frequency characteristic frequencies can be stored, and correction made for the gain-vs-frequency characteristic of an amplifier or amplifier chain. The correction factors are typically measured in final test of the sampling network analyzer, and programmed into a PROM that is incorporated into the particular sampling network analyzer.

Abstract: An improved Sampling Network Analyzer is disclosed, in which synchronization of the sampling of one or more input signals, either voltages or currents, is effected by means of a phase-locked loop (PLL). A reference signal serves to synchronize a phase-locked loop, which in turn synchronizes sample-and-hold circuits utilized for measurement. A C preset counter permits the operator to set a desired number of samples per measurement. A Y preset counter maintains the voltage-controlled oscillator within a predetermined (relatively narrow) range of frequencies. Operation of the sample-and-hold circuits is at a frequency that is related to the reference frequency by the ratio of two integers. A D preset counter is provided in the reference signal path to allow the Sampling Network Analyzer to be synchronized to a subharmonic of the reference frequency where the reference frequency is too high to permit the desired number of samples per measurement within a single period.

Abstract: A circuit for indicating the approximate energy content of the most significant transient appearing on an electrical power line within a predetermined interval is disclosed. An input to a first threshold comparator (326) may be set by the user to mark the nominal minimum amplitude (V.sub.2 ) of voltage transient whose energy content (volt-second area) is to be recorded. The transient impulse voltage integrator (401) is turned on when the impulse amplitude exceeds a preliminary threshhold (V.sub.1) lower than the nominal amplitude (V.sub.2) under control of a second comparator (325) and flip-flop (423). When the transient impulse amplitude equals the nominal amplitude (V.sub.2), a latch (431) reading a digital converter (430) at the output of the integrator (401) is clocked to permit display of the accruing integrator. While the integration proceeds the threshold of the second comparator (325) is increased from V.sub.1 to V.sub.

Abstract: A circuit for ascertaining the direction of origin of the most significant transient appearing on a electrical power line within a predetermined interval is disclosed. Threshhold comparator circuit (325, 326) are provided to insure that transient polarities needed for the directivity determination are ascertained while the transient impulse is still rising towards its peak value. For any nominal, user-set threshhold (V.sub.2), a lower preliminary threshold (V.sub.1) is automatically set and when the transient exceeds the preliminary threshhold, the transient polarities are determined and correlated to effect a tentative directivity determination which is stored in an input latch (205). When the transient exceeds the nominal threshhold, the directivity determination is transferred to an output latch (211) to be read by an output printing device.