Abstract: A device for measuring a physical quantity by time-division coding includes a source (1) capable of generating light pulses; a coder (2), the position of which depends on the value of the physical quantity, a sensor (4) including apparatus (5) for sending the light pulses to the coder (2) and a receiver (6) for receiving the coded light pulses, and an analyzer (7) for analyzing the coded light pulses connected to the sensor. The source (1) is capable of generating light pulses simultaneously at two different wavelengths (.lambda.1, .lambda.2), and the sensor (4) is provided with apparatus (9a) for separating the light pulses on the basis of their wavelength, the light pulses at a first wavelength (.lambda.1) passing through the sensor (4) and being coded, while the light pulses at a second wavelength (.lambda.2) are returned to the analyzer (7) to constitute pulses for triggering the sensor.