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(This workshop was given @ UNSW on 1 Sept. 2017. If you find any errors in this text, feel free to file an issue here )
What You'll Need
- A computer (Windows/Mac/Linux)
- A 3-button mouse (Useful, but not necessary)
- Motivation to build the best darn PCB in existance
Prelude - Installing KiCAD
Grab it here: http://kicad-pcb.org/download/
There are binaries available for all major operating systems.
Special note - Linux users
If you are using Linux, you may additionally want to install
kicad-library-3d as these aren't included by default.
Creating a Project
- Fire up
Needed an excuse to (finally!) learn KiCAD, so I decided to build a voltage controlled oscillator (sawtooth core). It's inspired by the early Elektor Formant synths, and designed to integrate with existing Eurorack synthesizer systems.
In the video I'll also talk about how I breadboarded up a MIDI to 1V/octave converter to go with it for keyboard/computer control.
See YouTube description for timecodes.
KiCAD design files: https://github.com/schnommus/formant_vco_prototype
Code I wrote for the PADI IoT stamp in the video for MIDI/CV conversion: https://github.com/schnommus/padi-midi-cv
Hadn't originally planned on publishingRead the rest...
In this video I demonstrate my progress so far on building an intelligent LCD display upgrade for the HP 141T.
I use an STM32F746G discovery board with a 4" touchscreen, and demonstrate a few neat features:
- Real-time spectrum display with graticules etc, that works on the slowest up to the fastest timebase
- A waterfall display mode
- A normalization function that makes insertion loss measurements much easier.
I also take a brief look at the codebase (which is very hacky at the moment!)
GITHUB REPO: https://github.com/schnommus/stm32_hp141_lcdRead the rest...
Was lucky enough to get this featured on Hackaday! See: Rapidly Prototyping RF Filters
A guide to simulating microstrip filters in QUCS and prototyping them with copper tape on blank FR4 sheets. These super-cheap materials are good up to a couple gigahertz, as you'll see in the video.
Following a quick real-time demonstration, I simulate and build 2 microstrip filters, a 1GHz stepped-impedance LPF, and a 10GHz end-coupled BPF.
(Checkout the youtube description section for active timecode links)
2:05 - 1/4 wavelength stub build & tests
3:46 - Radial stub build & tests
4:18 - Stepped
Building a mixer based on the LTC5548 14GHz MMIC by LT, and a TCM1-83X+ by Mini-Circuits [plus bonus bodge wires ;)]
After measuring LO leakage, conversion loss and IIP3 at different frequencies, I build a poor-man's tracking generator with it.
I also talk (perhaps a bit too much) about HP's old signal identifier feature on my 8555A.
Thanks to LT and Mini-Circuits for providing samples of the components used in the video, I've definitely got bigger plans for these parts!
Design files are available at my other web page on this: http://sebholzapfel.com/2-14ghz-mixer-pcb-open-hardware/
An article I did on theRead the rest...
Taking apart an old NDK 48MHz ovenized crystal oscillator from the 80s, making some measurements; and taking macro shots of the quartz.
I make some initial frequency measurements before taking it apart, and then after ripping out the crystal I run it through a tracking generator to look for resonance peaks.
Interestingly the crystal seems to operate at a slightly different frequency to what's written on the OCXO packaging, and the 'big' crystal package actually has a small one buried inside!
I repair an old APLAB ZD3203 DC Lab Power Supply that I rescued from the dumpster.
It had 2 big issues, one with extremely dodgy pots and another with output transients when turning it off.