Signal analyzer
Measures magnitude and phase of signals using digital techniques.
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A signal analyzer uses digital methods to pull useful information from an electrical signal, measuring both the magnitude and phase of the input at a single frequency within its IF bandwidth. The term commonly covers both spectrum analyzers and vector signal analyzers. While a spectrum analyzer only shows signal amplitude, a signal analyzer—when equipped with the right software—can examine any signal characteristic, such as modulation. Modern high-frequency models achieve strong performance by refining both the analog front end and the digital back end.
Quick Facts
- Type
- Measurement instrument
- Related terms
- Spectrum analyzer, vector signal analyzer
- Key technology
- Superheterodyne receiver, I/Q sampling
Facts from the source article.
Lore & Background
Modern signal analyzers use a superheterodyne receiver to downconvert a portion of the signal spectrum for analysis. The signal is first converted to an intermediate frequency and then filtered in order to band-limit the signal and prevent aliasing. The downconversion can operate in a swept-tuned mode similar to a traditional spectrum analyzer, or in a fixed-tuned mode.
In the fixed-tuned mode the range of frequencies downconverted does not change and the downconverter output is then digitized for further analysis. The digitizing process typically involves in-phase/quadrature (I/Q) or complex sampling so that all characteristics of the signal are preserved, as opposed to the magnitude-only processing of a spectrum analyzer. The sampling rate of the digitizing process may be varied in relation to the frequency span under consideration or the signal may be digitally resampled.
Reader's Guide
Signal analyzers can perform the operations of both spectrum analyzers and vector signal analyzers. A signal analyzer can be viewed as a measurement platform, with operations such as spectrum analysis (including phase noise, power, and distortion) and vector signal analysis (including demodulation or modulation quality analysis) performed as measurement applications.
These measurement applications can be built into the analyzer platform as measurement firmware or installed as changeable application software. The instrument's significance lies in its ability to measure any aspect of a signal, not just amplitude, through digital techniques and flexible software. By optimizing both the analog front end and the digital back end, high-frequency signal analyzers achieve good performance for a wide range of measurement tasks.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Signal analyzer (CC BY-SA 4.0).
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