| 摘要 |
Apparatus and methods for retrieving bipolar, standardized, digital communication words for test purposes from a source transmitting over a system bus, and displaying these communication words in an understandable format. The apparatus incluldes signal receiving ports coupled to the desired bus, which monitor and retrieve preselected communication words that are transmitted to one or more line replaceable units connected to that bus. Each incoming communication word contains an encoded label which is repetitively compared to a preselected label so that only those communication words having matched labels are retrieved for display. The retrieved word is decoded in either engineering or binary form and then displayed at an LCD window, printed out as hard copy, or made available to an IEEE-488 interface. Since the same label may be used to identify different communication words depending upon the transmitting source and bus, the apparatus includes an internal data base which utilizes the label and a transmitter identification code to generate data defining the selected communication word in proper engineering units and units of measure regardless of the system bus accessed. The apparatus includes signal input conditioning circuitry including two parallel comparators to convert the incoming bipolar signals into unipolar, NRZ data, data clock sync and gap signals used in downstream digital circuitry. |
