This is an oscillator circuit that can be used for calibrating frequency counters, amateur receivers and frequency meters. This circuit is called 2MHz standard with dividers circuit. This circuit uses two crystals, 100kHz and 2 MHz. Here is the schematic diagram of the oscillator part of the circuit:
This circuit is then can be combined with two 7490 decade counter , that is fed by the crystals through isolation amplifier. This circuit also divide the frequencies by 100, 20, 10, 4, and 2 for each oscillator. All frequencies is usable and rich in harmonics through 144MHz. For all mode of operation, the ground at pin 1 must be tied to common terminal. The counter reset gates at pins 7, 6, 3, and 2.