Experiments with decoupling capacitors
Capacitors are placed into a test bed in parallel to a 25 Ohm system impedance.
Transmission attenuation is an indication of the capacitors qualities as a decoupler.

expermiments with decoupling_capacitors (pdf, 6.8 MB)

The following two articles have appeared in DUBUS magazine and in DUBUS Technik book VI, pages 139 to 179: "Low noise VHF crystal oscillators"

Simulation of  quartz crystals and oscillators with SuperCompact / Serenade / ARRL  Radio Designer.
The resonator itself, removal of parasitics, maximizing Q on the working frequency, frequency pulling,
Text in German & English.

VHF Crystal Oscillators part 1 (pdf, 320 KB)

Simulation of crystal oscillators with Ansoft Serenade / Harmonica.
Sustaining amplifier, crystal dissipation, wild oscillations, 1/f noise, 1/f noise up conversion,
balancing noise close to the carrier vs. wideband noise,
negative impedance oscillators, Butler oscillator, things that can go wrong.
Text in German & English. pdf needs some editing work. This is the last WinWord version.
The printed version was done with PageMaker.

VHF Crystal oscillators part 2 (pdf, 305 KB)

13 dBm 5 to 100 MHz reference frequency distribution Amplifier (pdf,  1.6 MB)

A 220 pV/sqrt(Hz) low noise preamplifier  (pdf, 4 MB)

             V2 zip file with updated circuits, bom, gerbers  (1.1 MB)

Noise Measurements On Chemical Batteries (pdf, 3.4 MB)

Noise Measurements On Some Laboratory Power supplies (pdf, 3.4 MB)

Noise Measurements On Some Zener Diodes and Voltage References

Noise Measurements On Some Voltage Regulators

Frequency Doubler and Distribution Amplifier for Lucent KS-24361  (pdf, 6.7 MB)

Tuning Properties of some commercial VCXOs  (pdf, 50 KB)

Getting Logarithmic Sweeps Over 7 Decades With An Agilent 89441A Vector Signal Analyzer Under Network Remote Control

VHDL modules: Sine /Cosine function for direct digital signal synthesis, programmable pipeline delays for most standard types, signed/unsigned/fractional/real/integer conversions:

Sine / cosine package in VHDL   (external link to

Power Up/Down sequencers in VHDL   (external link to