Analogue-to-digital converter and analogue-to-digital conversion system embodying said converter

Analogue-to-digital converter outputting a value V of an electric signal coded on a number of bits N, comprising:

• electro-optic means of phase modulation on a predetermined interaction length L, receiving an optical input signal and the electric signal to be converted, and outputting a first and second optical signal having with respect with each other a differential phase that varies linearly function of said electric signal to be converted;
• an opto-electric device into which the first and second optical signals are input and that outputs at least a first and second electric signal, which are functions of the sine and cosine respectively of said differential phase;
• coding means to extract absolute values of the first and second electric signals in digital form coded on [N-3] bits, said coding means having maximum coding dynamics adjusted to code absolute values with reference to a differential phase included in a home sector which will be one of the four possible consecutive sectors partitioning the trigonometric circle into 2 .pi. radians;
• transcoding means outputting said value V, by coding said differential phase on N bits, starting from absolute values coded on [N-3] bits and the given home sector.