This circuit uses a 100 kHz crystal, but nearby frequencies can be obtained with appropriate crystals. Components are still common today.
April 2017 - New Texas Instruments DRV8x brush motor drivers for 1.7 to 8 A currents and voltages...
Found in EEE documentation, this circuit can have the duration and frequency adjusted separately....
January 2017 - Mouser Electronics already has in stock the Epson TCXO TG2016 crystal oscillators for use...