What is an RF Spectrum Analyzer?
Although spectrum analysis equipment and technology has been adapted for optical, audio, and other applications, the radio frequency spectrum analyser was developed specifically to characterize RF signal behavior over a given frequency range. The display convention for RF spectrum analysis has remained virtually unchanged, with the radio frequency visible on the x (horizontal) axis and the signal power (amplitude) plotted using a logarithmic scale on the y-axis. Modern RF spectrum analyzers also provide detailed insight into channel utilization, signal phase, and modulation properties.
The wireless revolution has driven higher RF spectrum utilization and channel density, along with more interference sources. Duplexing and multiplexing options squeeze more bandwidth out of airwaves and fiber while mmWave shifts frequency allocation closer to the edges of the RF spectrum poster. Despite these advancements, the RF spectrum analyzer remains the best option for verifying and troubleshooting RF performance from the concept phase to the field.
VIAVI RF Test Solution Features
The real-time spectrum analysis (RTSA) technology developed by VIAVI provides a foundation for a host of new portable RF analysis features. Along with automated workflows, cloud connectivity, and vastly simplified reporting, these advanced features address the evolving needs of RF service providers, field technicians, and contractors.
- Persistence Spectrum Analysis utilizes advanced algorithms to precisely measure the presence of a given frequency within the signal over time. This method allows “hidden signals” that might otherwise go undetected to be displayed and quantified. With time division duplex (TDD) transmission mandatory for 5G carriers above 3GHz, persistence spectrum analysis is an outstanding tool for characterizing 5G signals with precise uplink and downlink time slots over the same frequency.
- Signal Analysis has developed as an offshoot of RF spectrum analysis to provide detailed information on the amplitude and phase relationships between signals and their modulation characteristics. Signal analysis capabilities in a portable RF spectrum analyzer are essential for 5G and LTE modulation analysis, channel mapping, and conformance testing to 3GPP standards.
- Interference Analysis converts spectrum data into meaningful information on the source and type of unwanted signals impacting WiFi or cellular networks. RF spectrum analyzer replay features, interference hunting tools, and advanced heat-mapping software can be used to pinpoint interference sources quickly and easily.
- RF over CPRI (RFoCPRI) capabilities pioneered by VIAVI provide a useful method of RF measurement through the fiber fronthaul, which is the link between the baseband unit (BBU) and the remote radio head (RRH) in a wireless network. RFoCPRI conveniently allows mobile device uplink signals and interference high in the tower to be analyzed seamlessly from the ground.
- Beam Analysis is a useful handheld RF spectrum analyzer feature developed for over-the-air (OTA) performance testing in 5G beamforming applications. A 5G beam analyzer can characterize the transmission profile of each individual beam ID, including beam power and signal to noise ratio (SNR).
- Massive MIMO arrays enabling dynamic user-based coverage and millimeter wave transmission present unique challenges for antenna and coverage validation. 5G spectrum analysis tools designed to accurately interpret signal behavior in the FR2 (mmWave) spectrum and provide coverage mapping in real-time are essential new capabilities for 5G MIMO deployments.
RF Spectrum Analysis Use Cases
RF spectrum analyzers in the field are used to measure frequency utilization and interference within and between telecommunications networks. A portable RF spectrum analyzer can also determine the accuracy of a wireless transmission by comparing the frequencies and bandwidths of an output signal to the received input signal. The spectrum analyzer has become a valuable laboratory and manufacturing tool, as new RF components and topologies are developed and deployed.
- Cell Tower Installations utilize advanced RF spectrum analysis to expand the reach of 5G wireless services and verify performance KPIs at turn-up. Real time spectrum analysis with persistence spectrum is a must-have for analyzing advanced 5G transmission options like time division duplex (TDD) and dynamic spectrum sharing (DSS). With miles of new fiber and scores of new antenna arrays accompanying each new installation, the best all-in-one RF test solutions from VIAVI also include useful fiber and antenna verification capabilities.
- RF Shielding is an ongoing concern for legacy cable networks connecting businesses and homes as well as coaxial RF antenna connections. Damaged or missing RF shielding can lead to induced interference from escaped signals (egress) or leakage into the cable that interferes with wired transmission (ingress). Each scenario benefits from purpose-built RF spectrum monitoring solutions to locate and eliminate leakage sources. A handheld RF spectrum analyzer can verify electronic equipment emissions and conformance to electromagnetic compatibility (EMC) standards.
- Electromagnetic Fields (EMF) are harmful to humans over certain thresholds. Mobile service providers must continuously take radiation measurements to ensure regulatory compliance as well as the personal safety of employees and customers.
- WiFi Applications are challenged by interference, capacity, and channel overlap issues as the number of WiFi networks, users, and devices increase. RF spectrum analysis is a useful tool for diagnosing channel utilization and measuring signal strength. A WiFi RF spectrum analyzer in the field assesses the coverage and channel health, while identifying the least crowded channels to use as access points. This information helps operators optimize and troubleshoot WiFi networks more efficiently.
How Does an RF Analyzer Work?
The RF spectrum analyzer distinguishes itself from the oscilloscope by quantifying signal behavior in the frequency domain as well as the time domain. The heterodyne (swept-tuned) type RF spectrum analyzer was industry standard for decades. The familiar amplitude vs. frequency measurement was completed by down-converting incoming signals and sweeping them through a resolution bandwidth (RBW) filter. An additional detector then calculated the amplitude value for each frequency displayed on the screen.
- Real Time Spectrum Analysis
A conventional swept-tuned RF spectrum analyzer only provides a snapshot of signal amplitude at a given point in time. This method works well for stable or consistent signals, but is less useful for diagnosing unpredictable, intermittent, or transient signal and noise components. To overcome these limitations, RTSA technology uses digital processing power to increase the sampling rate and continuously store the results, providing a more complete analysis.
- 5G Spectrum Analysis
Radio frequency interference (RFI) is a common 5G RAN issue leading to performance problems including reduced data throughput and compromised voice quality. The interference source can often be transient in time as well as frequency. RTSA is an effective tool for 5G spectrum analysis, along with a persistent spectrum display to present thousands of data points simultaneously. Color and brightness are used to graphically represent the probability of a given signal appearing.
RF Spectrum Analyzer Solutions from VIAVI
- OneAdvisor 800
The VIAVI OneAdvisor 800 is multi-purpose portable RF spectrum analyzer ideal for verifying and troubleshooting RAN networks. An impressive list of RF spectrum analysis features is highlighted by real-time persistence spectrum for 5G FR1 (9KHz to 6GHz), RFoCPRI interference analysis, O-RAN fronthaul verification, and advanced interference location capabilities. The OneAdvisor 800 also performs cable and antenna reflection testing, fiber inspection, and OTDR testing using pre-configured test workflows.
- CellAdvisor 5G
The CellAdvisor 5G is the industry’s most comprehensive and easy-to-use portable 5G spectrum analyzer, designed to confidently address the complexity of 5G spectrum analysis. RTSA, interference analysis, and persistence display features support both FR1 and FR2 (mmWave) frequency ranges. 5G carrier scanning measures up to eight carriers’ power simultaneously while 5G beam analysis characterizes individual beam ID, power level, and SNR. Fiber and coax test features compliment advanced fronthaul, interference, and PIM detection capabilities over CPRI.
- CellAdvisor RF Analyzers
The model JD746B and JD786B CellAdvisor RF Analyzers combine RF spectrum analysis, cable and antenna testing, channel power measurement, and interference analysis over CPRI in highly portable cloud-enabled instruments. While the JD746B supports spectrum analysis in the 100 kHz to 4 GHz range, the JD786B covers a full range of frequencies from 9 kHz to 8GHz.
The InterferenceAdvisor is a fully automated RF interference hunting solution designed for seamless integration with a OneAdvisor RF spectrum analyzer. The InterferenceAdvisor software, loaded onto an Android tablet, analyzes RF spectrum and power data while in transit. An intuitive heat-map effectively guides the RF technician to the area identified as the likely interference epicenter.
- WiFi Advisor
Home WiFi and LAN networks have become more complex and dynamic as premium services grow in popularity and channel density increases. At the same time, non-WiFi interference can often hinder performance. The WiFi Advisor utilizes an RF spectrum analyzer for PC to increase WiFi network visibility. The SmartChannel Wizard summarizes the health of each individual channel selected. Throughput, overlapping channel profiles, and noise ratios are graphically illustrated for easy diagnosis.