Rubidium_Standard.php 8691 Bytes 12-02-2018 11:23:31
Rubidium Frequency Standard ... from the Bay
Too seductive were those Efratom LPRO-101 on the bay, waving a flag "buy me".
Efratom LPRO-101, inside view
✈ Motivation
Not only the bargain offers in the bay, but also as a backup system for the hp58503B (GPS disciplined OCXO) made it necessary to have such a
nice thing.
As there is almost everything done, we may use the space and time (saved) to build an interface with some additional features.
An Atmega 8 reads some analog voltages like supply or lamp voltage and feeds an lcd with the data. The words "locked", printed
on a screen or display are more informative than just a led, which when not lit mayst be defective. Beyond that, it is the occasion to learn this ADC stuff, sleeping
(up to now) in the Atmega :-)
✈ The Circuit
The circuit is straightforward. The power supply has been designed out of the case. This allows for battery powering, when necessary. As the
power consumption of the Atmega 8 and the lcd is low, a linear regulator generates the +5V out of the +24V. Regarding the output of the LPRO-101, it has series resistors
of two times 10kΩ inside, so we added a shunt of 4kΩ. This guarantees, that the analogue inputs of the Atmega stay below 2.5V. None of those
measurements are time critical, so running at 1 MHz is absolutely sufficient. The circuit was realised on a double sided pcb. In case the serial
comunication is used, the crystal may be adapted, depending on the datarate.
✈ The Result
✈ Appendix : Service Manuals
✈ Notes / Hints
If you use the CodeVisionAVR don't forget to change the settings for the float to string conversion.
Thank you Mario for pointing me to this important setting !
✈ Share your thoughts
The webmaster does not read these comments regularely. Urgent questions should be send via email.
Ads or links to completely uncorrelated things will be removed.
Your Browser says that you allow tracking. Mayst we suggest that you check that DNT thing ?