Abstract: An improved analog preprocessor for a jaw tracking device having a plurality of magnetic sensors (44), each of which produces a first analog signal corresponding to the position of a magnet fixed with respect to the patient's mandible. The preprocessor includes analog means (200) for electrically combining the first analog signals to produce at least one analog position signal representing the position of the magnet along one axis, a gain select circuit (302) for providing a gain select signal, a variable slope ramp generator that provides a ramp signal having a slope corresponding to the gain select signal, a comparator for comparing the position and ramp signals and generating an output pulse having a length corresponding to the magnitude of the position signal, and a low pass filter for receiving the output pulse and producing an analog movement signal having a magnitude corresponding to the pulse length.

Abstract: A magnetic field sensor for use in a jaw tracking device. The sensor includes a Hall effect generator (110) and a pair of flux concentrators (112, 114). The Hall effect generator has first (116) and second (118) sensing faces disposed on opposite sides of the generator. Each flux concentrator comprises a strip of concentrator material formed into a U-shape, with a pair of opposed, mutually parallel side members (120, 122, 130, 132) interconnected at one end by a cross member (124, 134). The generator and flux concentrators are positioned such that the cross members are adjacent and parallel to the respective sensing faces, with the side members extending away from one another in a direction normal to the sensing faces. The sensor also preferably includes a metal-filled adhesive (140) having a high thermal conductivity bonding each cross member to its respective sensing face.

Abstract: A system for illuminating respective lamps to indicate the deviation from an optimum position of a kinesiograph sensor array in the anterior/posterior, vertical and lateral directions. The lamps are mounted on a panel in three sets of two corresponding to the three orthogonal axes. The panel is positioned on the chest of a patient during use so that it is in the same field of vision as the sensor array.

Abstract: A system for storing time-varying kinesiograph waveforms and continuously displaying the stored waveforms on the screen of a cathode-ray tube (CRT). In a recording mode, the waveforms are periodically sampled, digitized, and then stored in a block of random access memory reserved for that waveform. In a display mode, the Y axis of the CRT is driven by a digital-to-analog converter which receives digitized samples from the memory block corresponding to the displayed waveform. The X axis of the CRT is driven by a second digital-to-analog converter, which, in an X-Y mode, also receives digitized samples from a selected block of memory. In a sweep mode, the X axis digital-to-analog converter receives the continuously incrementing memory addresses, which read out digitized samples from the memory block for the displayed waveform. The system may also display an expanded portion of a waveform in the sweep mode by incrementing the memory address from one of several predetermined values.

Abstract: A system for measuring and displaying the coordination, duration of and interval between contractions of the masticatory muscles. Several electrodes, each associated with a masticatory muscle, generate signals responsive to muscle contraction. The electrode outputs are amplified, rectified and filtered, and then applied to several circuits, depending upon the operating mode selected. In a first mode, the filtered outputs are integrated during each muscle contraction and displayed by an electronic bar graph. The output is also applied to a threshold circuit which identifies the start and finish of the muscle contraction. The output of the threshold circuit is then processed by a timing circuit which determines and displays in digital form the duration of the muscle contraction and the interval between contractions.