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  100 MHz to 6 GHz
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PLL Oscillators from 100MHz to 6GHz

This project was started because Oscillators are important components for OMs still building their own equipment like transverters or Tracking Generators.

Next decision was to use a phase locked loop design instead of the usual injection oscillators which produces a lot of unwanted signals.

The princip of the Phase Locked Loop Oscillator. A High Frequency Voltage Controlled Oscillator which operates direct at the wanted frequency and a Low Frequency Crystal Oscillator are divided down and then synchronized to a common (comparison) frequency with a PLL IC. At Frequencies higher 4GHz an additional Doubler,at Frequencies below 400MHz add. Dividers are used. Important to know is that the frequency stability only depends on the Low Frequency "Reference" Oscillators. For example a crystal oscillator 10Mhz with 10ppm drift means 100Hz at 10MHz, but 10KHz at 1GHz Output Frequency.
Therefore the internal Reference Oscillator is either a 10MHz TCXO or VCTCXO
with 4 stability options from -10°C to +70°C, +/-1ppm, +/-0,5ppm +/-0,25ppm or +/-0,1ppm (measured) specified 0,5ppm from -30°C to +85°C.
Also possible is the use of an external Reference Oscillator, like OCXO, Rubidium or GPS Frequency Normal what gives excellent Frequency Stability.

Another important Issue is the Noise Generation especially close to the carrier. This is determined by the PLL IC,the VCO,the Loop Filter in the "Voltage Control Line" and the Noise of the Reference Oscillator. So care has to be taken by use of an external Reference !!!


Last but not least, a little micro-controller is necessary to program the PLL IC. Two Pins of the controller are free and can be used to switch between 4 programmed Frequencies within the Bandwidth of the VCO. Another Option could be to use an external controller board with 8bit switch

With these versions almost all frequencies are possible from 100Mhz up to 6100MHz.


Please note that this is for Radio Amateurs Only for a price which includes only components cost and a little margin for energy, tools and new interesting components or hobby projects.

Nevertheless as there is some money turnover, I founded a Small Buisness.

Click on the Photos to enlarge and close with Back Buttom !