Wide-band discriminators utilizing internal feedback

1,046,806. Frequency discriminators. CSFCOMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. Aug. 7, 1963 [Aug. 7, 19621, No. 31245/63. Heading H3A. An F.M. wave is applied in push-pull through two paths to a phase detector 3, one path ineluding a fixed value delay line 5 and the other a phase shifter 4 phase shifting its input by p.#/2, where p is an integer 1, 2, 3 or 4, depending on the output of the phase detector 3. This output as it increases or decreases below voltage levels determined by a limiter 6, actuates through a relay to switch in one or more of four delay line sections each delaying by #/2 the input to phase shifter 4. Thereby a wide-band frequency discriminator is obtained unresponsive to mean frequency slow variations and suitable for magnetometer optical pumping measurements.