It handles all communication with the RF blocks and samples the ADCs. The central element is the Spartan6 FPGA.The ADCs are sampling the final IF with section:.Each receiver consists of two down-convert mixers.It also avoids potential isolation issues that could arise if the receive paths would merge into a single mixer/ADC. This increases BOM cost but allows measuring two parameters at once (S11 and S21 or S22 and S12). Both ports have completely separated receive paths.Instead of directional couplers, resistive return-loss-bridges are used (easier to implement for wide bandwidth).In each signal path, two RF switches are used in series to achieve higher isolation between the ports. The stronger part of the signal can be routed to either port.

After the amplifier(TRF37A73) the signal is split and the weaker part of it fed into the reference receiver.

The stimulus signal power can be adjusted between approximately -42 and -10dbm with a digital attenuator (RFSA3714).

Its output signal is slightly filtered to reduce the amount of harmonics.

The stimulus source for frequencies above 25MHz is a MAX2871.

Its own reference clock is either a 26MHz crystal or an external 10MHz signal. It also serves as the stimulus source for frequencies below 25MHz.

The main clock source is an Si5351C, providing all the required clocks for the different blocks.

You can try out the application without the PCB (obviously no measurements are possible, but you can import provided example measurements and get an idea about what it can and can't do). Everything else is handled in the PC application once the data is transferred via USB. The PCB is really only the RF frontend with some processing power. There are also some initial example measurements. Some specifications are available but this project is still under development and the specifications might change. If you notice bugs or have ideas for improvements, please create an issue for that.įor general questions or discussions, the LibreVNA group is probably the best place.

If you would like to control the LibreVNA with a script, see the SCPI Programming Guide.

An (incomplete) user manual is also available.If you would like to try out the newest features, the compiled versions of each commit can be found here (but keep in mind that some features might be unstable or incomplete).You can find released versions of the GUI application and the device firmware here.

Nanovna 6ghz