Abstract: A soft decision analyzer system is operable to interconnect soft decision communication equipment and analyze the operation thereof to detect symbol wise alignment between a test data stream and a reference data stream in a variety of operating conditions.

Abstract: An antenna, which may be a search coil, connected to an active circuit which provides negative impedances, each of which is of the order of magnitude of the positive impedances which characterize this active antenna. In one embodiment, one coil terminal is connected to an amplifier which drives a voltage-controlled current source that, in turn, drives a feedback coil which is coupled to the original search coil. In another embodiment that additionally exhibits an advantageous signal-to-noise characteristic, both terminals of the search coil are connected to a differential amplifier that, in turn, provides the control voltage for a current source, which, as in the first embodiment, drives the feedback winding. The feedback coil is wound to provide positive feedback by additive superposition of both coil fields.The positive feedback provided by the feedback current lowers the antenna impedance which, in turn, increases the effective area of the antenna.