A Spectrum Analyzer Based on a Low-Cost Hardware-Software Integration

Instruments are a very important tool for the good comprehension of any science. In the engineering electrical field, most of the practice laboratories are equipped with a large set of devices. One of the major challenges to get a complete laboratory is the economic cost. Professional electronic devices as multi-meters, oscilloscopes or spectrum analyzers are quite expensive on the market. Fortunately, with the aid of software-defined radio (SDR), low-cost equipment can be built. A fundamental device in these projects is the RTL-SDR dongle. This electronic accessory captures wireless signals and puts them on a USB port. Therefore, with digital signal processing it is possible to get access to low-cost instruments like spectrum analyzers. In this work, an integration of hardware and software is presented. An application is developed with Python and implemented on a Raspberry Pi3 B+. This proposal captures, demodulates, and displays AM and FM signals. The signals obtained can be observed on frequency or time or can be recorded as well.