Abstract: A narrow-band digital frequency-modulation (FM) limiter-discriminator (LD) receiver with two independent detectors that combine to remove most of the bit errors caused by FM-clicks in an encoded channel. The output of the LD circuit is presented to a sample-and-hold (S&H) detector and to an integrate and dump (I&D) detector. Because the S&H and I&D detector outputs are offset in time by one-half bit and they are not entirely correlated, an error in one does not necessarily imply an error in the other. Using convolutional coding and Viterbi decoding, with threshold-compensation of the I&D detector output and threshold- or envelope-compensation of the S&H detector output, averaging the two compensated detector signals improves the receiver bit error rate (BER) performance by more than 3 dB over the soft-decision thresholded I&D detector alone, which until now was believed to be optimum in the art.

Abstract: A curved visor mechanism for helmets with laterally moveable visors that move on guides that define a track attached to the helmet. The visors are curved in the shape of a sector of an annulus of a circle. Using such a shape allows the track defined by the visors to maintain a nonzero rake angle at the front of the face area of the helmet, while preventing retracted visors from extending too close to the bottom of the back of the helmet. Removal of the visors from the helmet is accomplished by removing sections of the guides in which the visors move, preferably at the front of the helmet. This creates notches in the guides through which a visor can easily be inserted into and out of the helmet.

Abstract: Computerized chart apparatus for selecting a shim to simultaneously adjust the toe-in and camber of the wheel assembly of a vehicle.

Abstract: Computerized chart apparatus for selecting a shim to simultaneously adjust the toe-in and camber of the wheel assembly of a vehicle.

Abstract: A gas pressure gauge tester utilizes the pressure equalization perforations in the face of a gas pressure gauge to introduce pressurized gas into the gauge to counterbalance the gas pressure exerted on the gauge from the gas within a storage cylinder associated therewith. The gas pressure gauge to be tested is captured within a bracket which has integrated thereto a conduit connector cooperatively positioned to seal the pressure equalization perforations such that gases may be introduced thereto from a regulated supply of pressurized gas in order to counterbalance the internal pressure of the cylinder associated with the gauge. The amount of pressurization necessary to counterbalance the gas pressure is indicative of both the operability of the gauge and the state of charge of the associated cylinder.

Abstract: An improved vehicle frame alignment gauge. The gauge can be readily installed and operated by a single mechanic. The gauge does not have to be attached to and suspended from a vehicle frame and does not have to be readjusted while the frame is being stressed to alter the shape of the frame.