10MHz Frequency Reference OCXO-T
Low cost, 10MHz high stability frequency reference for timing applications. (OCXO)
What is it?
It's a 10 MHz quartz square wave generator with an oven controlled crystal for high stability. It's applications range from a time base in frequency counter, to reference frequency for synthesizers etc. It contains a Japan made OCXO module that has been used in another product before being recycled, put in to this design, tested and trimmed by me. This mean you can have a very high quality frequency reference at a fraction of the price you would have paid if you used a new OCXO.
Why did you make it?
I needed a good, stable frequency source for my synthesizer projects to be small, affordable, and have high stability.
What makes it special?
I designed it to be a low cost and small module that can easily be retrofitted in to a Frequency counter or be used in your projects with out taking up much board space. The PCB measures 50x33mm (1.96x1.29 inch) and needs just 5V in. It takes about 500mA of current for the first minutes when the oven heats up the crystal to its operating temperature. It then stabilizes at about 200mA. The output level is 10dBm square wave in 50ohm. Measured in Volts that is 0 to 5V if not loaded and 0 to 2.5V if loaded at 50ohm.
There is a Voltage control Input that enables adjustment of the device +/-15Hz. The voltage that gives exactly 10MHz differs from device to device bit but is somewhere around 1.2 to 1.3 Volts. This Input is normally connected to a 30-turn trimmer feed by a 3,3V voltage regulator. I have adjusted it using a GPS derived comparison frequency so it is exactly 10,000,000.0 Hz By moving the jumper one can get control over the voltage trim input and the 10MHz out to the IDC connector. This makes it possible to use the oscillator in a PLL project for example to GPS discipline it.