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.
This article shows how to modify an inexpensive LNB to accept an external LO-reference signal in order to be used as a K-band downconverter for QO-100 (Qatar Es’hail 2) amateur radio sattelite reception, radio astronomy or similar K-band experiments.
The uBlox GPS-modules are capable of providing various reference clock signals through the TIMEPULSE pin. By default, this pin outputs a 1 pulse-per-second (PPS) signal. For an upcoming project, a GPS disciplined oscillator (GPSDO), this output had to be adjusted to 100 kHz. Instead of using the manufactuer’s software, u-center, this task is supposed to be accomplished using an Arduino. This article shows how to (dynamically) adjust the TIMEPULSE reference signal using an Arduino.
The so-called “infinite impedance detector” is a circuit that was commonly used in the old days of vacuum tubes. Since vacuum tubes can be somewhat considered to be heated JFETs, it is evident that such a circuit can also be built using a more modern, silicon-based approach. This article covers my first experiments with a BF256B based infinite impedance detector.
This article supplements to my article titled THD Measurement with an Oscilloscope and FFT, which appeared in Elektormagazine. Here I will explain how the formula to calculate THD-F from relative power values (in dBc) was derrived from the standard voltage-ratio formula. A more in-depth explanation of the entire subject can be found in my research paper titled Total Harmonic Distortion (THD) analysis utilizing the FFT capabilities of modern digital storage oscilloscopes.
Generating more complex arbitrary waveform files for modern test equipment doesn’t have to be difficult. For a recent project, I needed a stereo-FM multiplex (MPX) signal containing two different tones in the left and right stereo audio channels. This article is going to show how to generate such a MPX signal for Siglent SGD-series arbitrary waveform generators with Python and PyVISA.
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.
The NXP MRF101 series high ruggedness N-channel Enhancement-mode lateral MOSFETs promise over 100 Watt CW output power and slightly over 20 dB gain from 1.8 MHz all the way up to 250 MHz. Their mismatch insensitivity for a VSWR of greater than 65:1 without significant device degradation makes these devices extremely interesting for amateur radio operators. While there a plenty of designs for the HF + 6m Bands on the internet, I wanted to see what it takes to use them on the 2m VHF band.