IN3LBQ on the Hühnerspiel (Amthorspitze) - photo by IN3OTD

Electronic projects

Here you can find some of the circuits I have built in the past, in particular a 12-bit and 18-bit parallel port analog-to-digital converters with complete schematics and C source code for Linux

12 b ADC with PC parallel port interface

A simple analog-to-digital converter that interfaces to a PC parallel port and providing 12 bit of resolution, with four differential input channels. Actual conversion throughput is about 2.5 ksamples/s

High resolution ADC with PC parallel port interface

A high-resolution ADC : it can provide up to 18 bits plus sign, at 16 samples/s, with four differential or eight single-ended input channels.

A simple DDS controlled by the USB port

Characterization of the QRP2000 USB-controlled synthesizer.

Six-port vector network analyzer

How to build a vector network analyzer without explicitly measuring phase, but only voltages.

A wideband bias tee

How to design a bias-tee with nice performances, starting from an existing design by WB9JPS.

HP Disk on SD card

An HP GPIB disk drive on SD card emulator for old equipment.

(pseudo-)PIN diodes measurements

Measurements on several diode types to find out if they can work well as PIN diode on the HF band.

Diode power detectors

Measurement of a few diode power detectors configurations on the HF band.

Stuff modeling

Varactor capacitance modeling

Brief overview on how to extract a model for the capacitance-vs-voltage curve of a varactor diode, starting with the graphs on the component datasheet.

LDMOS modeling

How to extract a (small-signal) LDMOS model, starting from the device S-parameters, with some examples for common high-frequency LDMOS.

Homemade network analyzer calibration kit

Characterization and modeling of a homemade "calibration kit" (reference impedances) to be used to calibrate a network analyzer.

Magnetic cores measurements

Characterization of ferrite toroids and (big) beads foound in the junkbox.

Impedance fitting

Procedure to fit a predefined model to a measured impedance profile.