The circuit is made up, in addition to the input amplifier (MAV 11), of a chain of dividers: the first divides x 4 (UP582), the second x 64 (U664), the third x 125 (SN74167), the fourth x 125 (SN74167) the fifth x 250 (SN74167) to therefore obtain a total division of the input frequency of 1000. The transistor adapts the output of the U664 to the TTL level required by the 74167. The input circuit is SMD. The trimmer must be adjusted for maximum input sensitivity.