• Small step for a man, even smaller for the rest

    MS-BOSS12/09/2021 at 00:04 0 comments

    I have fixed all of the symbols / footprints which weren't finished earlier or got broken during data migration. The only part remaining is the TCXO. Slow progress, I know, but at least something, I guess.

    What needs to be yet checked schematic-wise:

    • footprints of electrolytics (check that the ones I desolder from boards at my work share footprint)
    • RS485 connector footprints
    • TCXO footprint

    All progress is stored on GitHub.

  • Awakening from the long sleep

    MS-BOSS11/21/2021 at 00:13 0 comments

    Why there was no progression for the last year

    Hi, after a long hiatus, I am returning with the aim to get back to electronics. Reasons of my long absence from this place included living in college dorms and not doing anything most of the time, drinking a lot (and not just that) and preferring photography instead of electronics and also general lack of interest. However, I am (once again) back - I moved to a flat, bought a new and fast computer, large monitor and it's also too dark outside for photography.

    So, what can you expect?

    Well, my aim is to build a self-contained microwave generator module which will serve as a basis for other projects to come. It will work up to 6.4, 9.8, 15 or 20 GHz depending on PLL used as they are pin compatible. Basically, there will be 5V power supply and some other device which will talk to the board using RS-485 (RS-232 mode may be added) and command the module. Then, there will be 4 output ports in 2 pairs - these are 2 differential 100 Ohm outputs (or 50 Ohm single ended outputs). The output waveform is unfiltered so it contains a large amount of harmonics - the use-case specific filters or a switched filter bank will be realised on another board.

    The device will also contain internal trimmable VCTCXO, external clock input (either balanced digital input or single-ended sine/clipped sine/square wave like a standard 10 MHz reference) and reference output which can output either the internal TCXO or the external reference. There will also be a DC / duty factor corrector to maintain 50% output duty so that the PLL is happy.

    The software should include support for (not necessarily for all the possible PLLs): monofrequency output, FSK and GFSK (2FSK, 4FSK, 8FSK or arbitrary level), setting output power in step of 0.25 dB (around 16 dB range), frequency ramp generation, phase adjustment, independent 2^N divider on the 2 output ports, AM, FM and PM modulated output (stepped). There will also be an expansion port for connecting a daughterboard using SPI. It will probably either be unused or just support LEDs and buttons for some basic input panel.

    It should be possible to get these possible PLLs work on this PCB:

    LMX2572 up to 6.4 GHz

    LMX2592 up to 9.8 GHz

    LMX2594 up to 15 GHz

    LMX2595 up to 20 GHz

    What is the state of the project?

    Currently, the schematics are nearly finished. There are still some remaining touches required, but it is nearly finished.

    Most of the unusual components already have their footprints. There are several remaining like the crystals to be checked and corrected.

    The PCB has the most important part already drawn. The PLL part is fully drawn and fit nice under a metal shielding. The rest shouldn't be as demanding as this part.

    All materials for this project are stored at https://github.com/MR-DOS/MWGEN-G1