Here is a Crystal based pulse generator that gives 50Hz clock pulses from its output. This circuit can be used as the front end of circuits that require precision 50Hz pulses.
The circuit uses two counter ICs CD4060 and CD 4017 to divide the basic frequency to generate 50 Hz pulses. CD4060 is the ripple free binary counter IC and its basic frequency is controlled by a crystal connected in its pin 10 and 11. A 4.9152 MHz crystal is used in the circuit to generate clock pulses. CD4060 divides the 4.9152 crystal frequency by 16,384 so that from the Q13 (output pin 3) 300 Hz clock pulses available.
These clock pulses are then fed into the clock input pin14 of CD4017. It is the Johnson decade counter that divides the 300Hz pulses into 50 Hz pulses which are available from its Q5 (pin1) output.