For multiplying frequencies in the 1-to 150-Hz range, this circuit uses a 4046B and a 100 prescaler. The VCO output
is phaselocked to the low-frequency input. This simplifies use of a frequency counter to measure LF signal frequencies. By using a 4017B and a 1-kHz. the circuit can be used as a 1-to 9-kHz frequency synthesizer or as a x10 frequency multiplier.