Abstract: Test device (DUT) current flow is mirrored through a capacitor. If the mirrored current is switched to bypass the capacitor, the capacitor discharges. Otherwise, the mirrored current charges the capacitor. The charging capacitor's voltage rise time is proportional to the DUT's IDDQ current. Several IDDQ reference values can be derived, each representing quiescent state operation of a defect-free copy of the DUT. An IDDQ test value is derived for each IDDQ reference value. Each test value represents quiescent state operation of the DUT after application of the test vector which produced the corresponding reference value. The reference values are compared to their corresponding test values and a plurality of scaling factors derived. Each scaling factor represents a proportionality between corresponding reference and test values. The DUT is “non-defective” if the scaling factors are equal within a predefined error range . Otherwise, the DUT is “defective”.

Abstract: According to the invention there is provided a method of signal coding that permits high speed data transmission over multiple pairs of UTP-5 cable from a transmission end to a receiving end which includes, at the transmission end, separating an incoming frame of data into a plurality of byte streams with a predefined sequence of bytes assigned to each of the streams, encoding every 2 bits of data in each stream into one of 4 logical voltage levels forming a symbol or quat thereby reducing the symbol or baud rate by 50% and inserting an escape sequence into one or more of the streams consisting of a sequence of zero's followed by a control code to indicate a transition from one state to another. At a receiving end, the method further includes reading the escape sequence and decoding the signals in accordance with the code contained in the escape sequence.