SDR receivers, or software-defined radio receivers, are devices that allow users to tune into and receive a wide range of radio frequencies using software instead of traditional hardware components. They have gained popularity in recent years due to their flexibility and versatility. Unlike traditional radio receivers, which are designed to receive specific frequencies and require specialized hardware, SDR receivers can be easily reconfigured to receive different frequencies by simply updating the software. This makes them highly adaptable and suitable for a variety of applications.