Abstract: A speech recognition system for recognizing the words spoken by identified speakers and unidentified speakers, based upon the use of three dimensional, polar coordinate expressions of formant information, which eliminate the differences in word patterns encountered among various speakers, and the content of a reference pattern memory which stores formant information as a reference pattern in polar coordinates. The input speech is subjected to LPC analysis for each of several analysis degrees and the resulting coefficients are time normalized against the reference pattern using a DP matching process, which may be on the basis of city block distances in order to determine the most appropriate analysis degree that represents the input speech.

Abstract: A voltage limiting circuit with two-terminal network character is described which has a sharp-edged limitation characteristic curve and a short response time. According to the invention, this is achieved by means of two current mirror circuits connected to each other in a ring circuit, with a clamping transistor being at the same time a transistor of one of these current mirror circuits. A biasing current is fed from a current source into the remaining elements of the two current mirror circuits, this biasing current subjecting the semiconductor junctions of these current mirror elements to current and charging the diffusion and depletion layer capacitances thereof already prior to the limitation onset. The consequence thereof is a rapid limitation effect when the limit voltages are being reached.