Abstract: A hand-held tuning device for stringed musical instruments consisting of two stroboscopic light sources of different colors (such as LEDs or semiconductor lasers) mounted on a guitar pick-shaped board complete with a miniature battery and the circuitry necessary to drive the light sources at standard frequencies of strings. A single pushbutton activates the device causing the two colored light sources to flash one at a time at the desired frequency while simultaneously engaging a miniature piezo buzzer that emits a tone of the same frequency. The device operates while the button is pressed; each subsequent press advances the frequency to that of the next string to be tuned. The instrument is tuned by plucking a string with the pick tip while directly observing the string for moving reflections of the two colored light sources, and subsequently adjusting the tuning until the two colored reflections are stationary relative to each other.

Abstract: A method and apparatus is disclosed for digitally compressing video signals. The method and apparatus provides a system which generates values related to the differences between respective pixel locations in an x, y pixel display. The differences generated between proximate pixel locations are used to generate various delta values which are encoded in an asymmetric fashion. The asymmetric coding eliminates artifacts in the displayed image, and the delta encoding is performed in both a horizontal and vertical direction. Errors due to the compression process are distributed randomly in both horizontal and vertical directions, approximating the effect of analog media such as video and especially film.