Software Defined Radios

- Overview

Software Defined Radios (SDRs) are affordable, flexible platforms that use software to control radio functions (modulation, frequency, etc.), allowing users to analyze, monitor, and even transmit across vast parts of the electromagnetic spectrum (EMS) for diverse applications like security, communication analysis, and learning, significantly cutting hardware costs compared to traditional radios. 

They replace dedicated hardware with programmable chips (FPGAs, DSPs) on a computer or embedded system, making them highly adaptable for everything from cellular signals to satellite comms. 

1. Key Aspects:

• Software-Controlled: Functions like filtering, modulation, and encoding are handled in software, not fixed circuits, enabling rapid updates and new protocols.
• Cost-Effective: Using commercial-off-the-shelf (COTS) hardware, they offer high functionality at a lower price point than specialized RF gear.
• Versatile Platforms: Can be reconfigured for different tasks (e.g., FM radio, Wi-Fi, 5G, radar) through software updates.
• Core Components: Typically feature an RF front-end (antenna, tuner) connected to a computer with an ADC/DAC and powerful processing (CPU, FPGA, GPU) for digital signal processing.

2. Common Uses:

• Spectrum Analysis: Monitoring and visualizing the RF environment, identifying interference, and planning frequency use.
• Wireless Security: Detecting and analyzing mobile devices, Wi-Fi, and other signals for security applications.
• Communications: Testing and optimizing cellular networks, developing new waveforms, and supporting tactical communications.
• Education & Hobby: Platforms like ADALM-Pluto provide accessible labs for learning RF.

- How Software-defined Radios Enhance Spectrum Monitoring and Recording

With the increasing prevalence of wireless devices, the Internet of Things (IoT), and 5G networks, the radio frequency (RF) environment is becoming increasingly congested, noisier, and more difficult to manage, with many services vying for the same resource: RF frequency bands. 

Against this backdrop, measuring and analyzing the RF spectrum at specific locations is extremely useful in many scenarios, providing mobile telecom operators with the means to optimize RF usage, prevent channel saturation, and make more informed wireless communication decisions. 

Furthermore, spectrum analysis is increasingly used in military operations and defense-related missions such as electronic warfare (EW) and signal intelligence (SIGINT) because it can detect and locate malicious or hostile signal sources. 

Therefore, spectrum monitoring and recording are fundamental functions of the modern RF industry, both civilian and military. 

To meet the pressing needs of modern civilian and military applications for RF spectrum monitoring and recording, numerous companies offer a range of solutions, from portable field devices to high-performance benchtop analyzers and advanced software platforms. 

The major vendors mentioned in the initial tips, such as Keysight Technologies, Rohde & Schwarz, Anritsu, and Viavi Solutions, are all industry leaders, and other well-known companies also provide specialized solutions.