METHOD FOR MEASURING INTERFERENCE ORDER AND DEVICE IMPLEMENTING SAID METHOD Russian patent published in 1994 - IPC

FIELD: measuring devices. SUBSTANCE: measured movement is converted to n interference signals, which are shifted in Π/n phase, from two interference signals which are shifted in Π/2 phase. This task is performed by electrooptic interference transducer. Four counting pulses for each order of interference are generated. These signals control counter during movement of object. Result of counting is stored in high indication bits of counting unit. Parallel code that is stable to noise is generated by logical processing of n interference signals. Low indication bits are stored in this code. Device implementing said method has laser, light-splitting cube, reference and measuring reflectors, modulator, optical prism, photodetector, stable frequency oscillator having n synchronous outputs which are connected to n balanced mixers. Second outputs of stable frequency oscillator are connected to photodetector output. Outputs of balanced mixers are connected to logical unit generating Gray parallel code through Schmidt flip-flops. Two high bits of parallel Gray code enter generator of counting pulses which output is connected to input of reverse counter. Weight of each pulse is Π/8, output of reverse counter is connected to high bits of indicator. Other bits of parallel Gray code are transferred from output of logical unit to low bits of indicator. EFFECT: increased speed and increased stability to noise. 2 cl, 2 dwg