Introduction In previous posts I looked at programming the Si5351A clock generator with the Arduino and also examining the I2C bus (Ref.1/2/3). In this post I examine the generation of quadrature IQ signals required in modern amateur radio SDR receivers. Quadrature IQ Signals Quadrature signals are 90deg out of phase. The I oscillator is cos(wct)… Continue reading Si5351 Clock Generator IQ Programming
Marine GMDSS/DSC VHF Decoder_b
Introduction In previous posts I looked at various aspects of GMDSS/DSC using Scicos (Ref.2/7). In the last post I built a BFSK Random Data Generator on GNU Radio and in this post I use the random data produced to test a BFSK BPF decoder on GNU Radio. BFSK BPF Decoder Schematic Figure 1 shows the… Continue reading Marine GMDSS/DSC VHF Decoder_b
BFSK Generator on GNURadio
Introduction In previous posts I have looked at various aspects of GMDSS/DSC using Scicos. In this post I look at a BFSK generator for DSC VHF using GNURadio. The advantage of GNURadio is that it can be directly interfaced with the RTL-SDR and can decode in real time. GNURC Schematic Parameter DSC VHF BFSK Fc… Continue reading BFSK Generator on GNURadio
Marine GMDSS/DSC VHF Decoder_a
Introduction In previous posts I looked at receiving GMDSS/DSC HF & VHF signals using a Windows 10 laptop with SDRangel & Multipsk as well as a RaspberryPi4B with Gqrx & GNURadio (Ref.1/5). I also simulated the VHF DSC signal using Scicos (Ref.2). In this post I will make an initial pass at decoding the VHF… Continue reading Marine GMDSS/DSC VHF Decoder_a
Marine HF Weather Fax on SDR-IQ
Introduction Several years ago I looked at receiving Marine HF Weather Fax broadcasts using the RTL-SDR & HF Up-Converter (Ref.1/2). In this post I will use the SDR-IQ HF receiver. The SDR-IQ was one of the first SDRs on the market and covers the HF band exclusively. I like it because it has excellent performance,… Continue reading Marine HF Weather Fax on SDR-IQ