# Real-Time Statistical Measurement of Wideband Signals Based on Software Defined Radio Technology
## 2 Advanced Electromagnetic Spectrum Measurement Capabilities  
There is a wide range of signals in the electromagnetic spectrum, with high variability not only in the frequency domain, but also in the other dimensions: time, amplitude, and space. New generation technologies exhibit random variations in the structure of the signals, requiring the development of measurement techniques that address all four dimensions of the electromagnetic spectrum. Considering that new communication systems and technologies are evolving rapidly, the ITU-R Recommendation SM 2039-2013 urges monitoring systems to extend their capabilities to accommodate signals specific to the latest generations of communication technologies [20]. As a result, electromagnetic spectrum monitoring is becoming more complex, especially when real-time monitoring capabilities must be addressed. The main element of an electromagnetic spectrum monitoring system is the spectrum analyzer (SA), which can be a swept SA or a real-time SA [21]. The difference between the two analyzers in terms of monitoring variable signals, not only in amplitude and frequency but also in phase, is worth mentioning. The sweep analyzer acts as a passband filter, given by the resolution bandwidth (RBW), that moves like a window and gradually monitors the frequency domain of interest (SPAN) at a sweep rate that is directly proportional to the ratio of SPAN to sweep time (SWT). Vector signal analyzers can measure both the magnitude and phase of the input signal at a single frequency within the intermediary frequency bandwidth of the instrument. As the significance of speed in frequency analysis increases, the traditional capabilities of swept SAs, which display measurements sequentially, are proving to be insufficient. To overcome this limitation, real-time SAs have been developed to simultaneously display the power of all frequency components within the achievable real-time bandwidth. Real-time SAs offer a significant advantage over swept SAs by providing instantaneous and continuous measurements across the entire frequency range of interest. Rather than sweeping through frequencies sequentially, real-time analyzers capture and process the entire spectrum simultaneously, enabling users to observe all frequency components in real-time. Real-time SAs utilize advanced signal processing techniques and high-speed analog-to-digital converters to capture and analyze wideband signals in real-time. Theseanalyzers can handle complex and dynamic signal environments, making them well-suited for applications involving broadband signals, wideband modulation schemes, and frequency-hopping technologies but these capabilities significantly increase the cost of the measurement system. This very high acquisition cost affects not only the scalability of such systems but also the flexibility in the context of mobility. Many recent studies [22; 23; 24] suggest a low-cost solution to replace such high-cost equipment in the form of Software Defined Radio technology. Software-Defined Radio (SDR) technology is a wireless communication system that uses software-based processing to perform tasks traditionally handled by dedicated hardware components, enabling flexibility and reconfigurability in radio communications. As with SAs, the performance of the SDR platform can affect the ability to measure signals with different bandwidths, resolutions, frequency ranges, etc. In [25], the Adalm PLUTO SDR platform was used to measure LTE signals, with a discussion regarding its ability to detect low amplitude signals. In addition, the Adalm Pluto SDR platform limits the instantaneous acquisition frequency bandwidth to 20 MHz, which restricts the monitoring of newer technologies, such as 5G or WLAN. Continuing in the same direction, [PERSON] et al. [26] tested three SDR platforms with different analog-to-digital converter (ADC) resolutions (HackRF one--8 bit, Adalm PLUTO--12 bit, NI USRP 2930--14 bit) showing performances comparable to a classic SA.