Introduction OFDM Orthogonal Frequency Division Multiplexing is a digital transmission scheme designed to give optimal data performance and selective fading protection over a band limited channel. Data is shared over a series of individually modulated carriers. OFDM is now pervasive over many different transmission systems. Typical applications include: Digital Television, DRM Digital Shortwave Broadcasting, DSL… Continue reading OFDM for SSB_USB
64QAM for LTE_5G
Introduction 64QAM or 64 Level Quadrature Amplitude Modulation is a digital modulation technique used as a basic building block within the OFDM Orthogonal Frequency Division Multiplexing waveform used in Cellular Telephony LTE & 5G networks (Ref.1). QAM modulation encodes information into the different amplitude and phase levels of a carrier wave. Construction One way to… Continue reading 64QAM for LTE_5G
WSJT-X FT8 Modulator – Scicos Simulation
Introduction In the previous posts I looked at MSK144 and FSK441 which are WSJT-X/WSJT digital communications protocols or so called “fast modes” used for Meteor Scatter. In this post I will look at FT8 (Ref.1 & Ref.2) which is part of the WSJT-X series of protocols used for weak signal communication over all the HF/VHF… Continue reading WSJT-X FT8 Modulator – Scicos Simulation
AIS GMSK Modulator – Scicos Simulation
Introduction AIS Automatic Identification System for Ships is a traffic system that uses VHF transponders on vessels to periodically send out location information. It was developed by Swedish inventor Hakan Lans and is similar in concept to the ADS-B transponder system used on aircraft for position reporting. AIS uses two VHF marine channels 87B (161.975 MHz)… Continue reading AIS GMSK Modulator – Scicos Simulation
AM Modulator – Arbitrary Waveform Generator
In the previous post I showed how we can create an AM Modulator with ScicosLab/Scicos. In this post we can use this file to create a .CSV file that can be used to drive an Arbitrary Waveform Generator so it can test equipment in our lab as required. Traditionally Function Generators only produced Sine, Square… Continue reading AM Modulator – Arbitrary Waveform Generator