High voltage power supplies can open interesting doors to research topics such as laser, x-ray, spark gap transmitters. And many other specialized niches. Unfortunately, laboratory grade high voltage power supplies are rather costly. Luckily, there is a much less expensive way to put high voltage experiments into the hobbyists reach. This article shows how to […]
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Diplexer with integrated Bias-T (Triplexer) for QO-100 and X-band microwave reception using LNBs
This article shows how to build a simple Triplexer (Diplexer plus integrated DC Bias-T) for use with commercial TV LNBs for QO-100 or X-band microwave experiments. Introduction When using modified, commercial LNBs for reception of the QO-100 amateur radio satellite or X-band microwave experiments, it is necessary to pass a clock-reference signal, a DC supply […]
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Tremolo DSP Effect for Arduino
This article continues my newly acquired interest in implementing digital signal processing algorithms on the Arduino GIGA R1 by showing how to implement a tremolo effect algorithm in software. After showing how to implement an Audio Loopback Device and a DSP Diode Clipping Algorithm for Overdrive and Distortion Effects on the Arduino GIGA R1 WiFi, […]
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DSP Diode Clipping Algorithm for Overdrive and Distortion Effects
This article shows how to approximate the behaviour of a regular diode in a mathematical equation and how to subsequently implement the behaviour in software. The DSP algorithm can be modified to implement different topologies, such as single diode clipping, dual diode symmetrical soft clipping or asymmetrical clipping. The easiest way to implement distortion through […]
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Arduino GIGA R1 WiFi | Audio Loopback Example
This article shows a basic sketch outline to use the Arduino GIGA R1 WiFi for audio DSP experiments. The sketch presented makes use of the Advanced Analog Library to implement a simple audio loopback device. UPDATE: There also is a German version of this article available on my German blog: Arduino GIGA R1 WiFi | […]
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SITOR-B / NAVTEX Test Signal Generation
This article shows how to generate valid NAVTEX message bitstream using an Arduino. The Arduino implements proper CCIR476 character encoding, SITOR-B forward error correction, synchronization and phasing signals. An entry-level function generator is then used as a FSK modulator on 518 kHz where it can be received by a NAVTEX receiver. UPDATE: There also is […]
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Tiger / Rat Tail for Handheld Radios
Handheld radios are getting more and more sophisticated and versatile. The bottleneck for modern handheld radios is often the stock antenna. There is an extremely simple yet very effective add-on called a “Tiger Tail” or “Rat Tail” to remedy this situation. This article is going to explain how to make your own. For less than […]
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850 MHz Scanner Preamplifier / Filter Project
This article shows how to use off-the-shelf parts to improve the performance of a radio scanner in the 800 – 900 MHz band. Furthermore, it shows how to expand radio coverage by using two different receive antennas at the same time. For some reason, my new BCD996XT scanner wasn’t working as expected on the statewide […]
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Circuit and PCB Design
I am excited to offer my skills on a freelance / 1099 basis. With the three modules Circuit Design, PCB Design and Prototyping / Testing I offer the whole production range from an idea to the final turn-key solution. Circuit Design Service Support through all critical phases of circuit design can be provided by me. […]
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DSSS / BPSK Clock Recovery with the Abracon ABFT
Clock recovery in Spread Spectrum applications and BPSK modulated signals can be somewhat tricky. There are no commercial solutions available solely for this task either. Or are there? This article shows a great off-label use of the Abracon ABFT. Clock recovery in a Direct Sequence Spread Spectrum (DSSS) receiver can be quite a challenge. Because […]
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