Posts tagged ‘Timebase’

Keithley 775A Programmable Counter TCXO Repair

In my last post, I did a teardown of the Keithley 775A programmable counter/timer. And while feeding a 10 MHz signal from my Rubidium frequency standard, I noticed that the measured frequency was significantly lower (9.9981 MHz) than the nominal 10 MHz reading and could not be compensated by adjusting the TCXO fine adjustment screw alone. My suspicion quickly turned to the temperature controlled crystal oscillator (TCXO). Continue reading ‘Keithley 775A Programmable Counter TCXO Repair’ »

Wavetek 395 Timebase Upgrade

I got a Wavetek 395 arbitrary waveform generator (AWG) last year. Unlike my other equipment (such as HP 8566B, HP 5350B, HP 8642B and Racal Dana 1992) which all came with high stability ovenized crystal oscillators, the Wavetek 395 only comes with a 100ppm crystal. While the stock timebase is perfectly fine for all but the most serious measurements, I decided to upgrade it to an oven controlled crystal oscillator (OCXO) as I happen to have a Vectron CO-717B58N lying around. Continue reading ‘Wavetek 395 Timebase Upgrade’ »