Analysers

Buying guide

The specification that settles an analyser purchase is the measurement band, because it decides whether the instrument can see what you need to see at all. A spectrum analyser rated to a few gigahertz will not help someone characterising a millimetre-wave link, and a network analyser calibrated for audio frequencies is the wrong tool for an RF filter. Read the frequency range first, then the resolution bandwidth or the dynamic range, depending on whether you are hunting small signals near large ones or measuring absolute levels. Everything downstream, the connector type, the port count, the available options, follows from getting that band right.

With that fixed, the second question is what you are buying into when the unit is used, and here it matters a great deal, because 97 percent of the listings are used. Calibration is the thing to verify. An analyser that has drifted out of spec still powers on and still draws a trace, so a clean display tells you nothing about whether the numbers under it are trustworthy. Ask when the instrument was last calibrated and against what standard, check that the options you are paying for are actually unlocked in the firmware, and confirm that any required probes or cables are included rather than assumed. On an older unit, the display and the fan are the parts that age first.

Price sits across a broad band. Units cost anywhere from EUR 1 to EUR 25.278, with an average around EUR 806. The low end of that range is accessories and simpler modulators; the instruments that carry the category, the signal and spectrum analysers, sit well up the scale. Buyers working to a budget will find that the used share is what makes the category reachable, since used and refurbished analysers listed for sale are more affordable than new equipment of the same class. Brand presence shapes the choice too: names such as APC, Lenovo, Powervar, Various, Cirrus Logic turn up repeatedly, and a model from a common line is easier to cross-check against a datasheet and easier to find spares for than an orphan from a maker who has left the market.

Types of Analysers

Networking analysers

Among the listings that specify a type, networking analysers are the largest group. These are instruments that sit on a data link and read what passes through it, measuring throughput, latency, packet loss and protocol behaviour on a wired or wireless network. A technician commissioning a site, or an engineer chasing an intermittent fault, reaches for one of these to see traffic the endpoints themselves cannot report. They differ from the signal and spectrum instruments further down this list in that they work at the level of the data stream rather than the raw waveform, so the output is counts and timings rather than a trace against frequency.

Audio modulators

Audio modulators generate and shape audio-band signals, impressing information onto a carrier or producing defined test tones for measurement. Where an analyser reads a signal, a modulator is on the other side of the bench producing one, which is why these appear in a test setup as the stimulus that an analyser then characterises. Broadcast engineers, audio-equipment developers and anyone validating a transmission chain use them to feed a known input and check what comes out. The audio emphasis sets them apart from the RF-oriented instruments here: the frequencies are those a person can hear, and the concern is fidelity and distortion rather than gigahertz-scale spectral content.

Communication analysers

Communication analysers test the links that carry voice and data, exercising a radio or a transceiver against a standard and reporting how well it conforms. One of these can emulate a base station, drive a device under test through its paces, and measure the quality of what comes back, which makes it the instrument of choice for servicing two-way radios, mobile equipment and other transmission gear. They overlap with signal analysers in that both deal in modulated signals, but the communication analyser is built around a protocol or an air interface and does the two-way work of testing a link end to end, not just observing a waveform.

Signal analysers

Signal analysers take an incoming signal and resolve it into amplitude, frequency and phase, letting an engineer see the structure of a modulated or complex waveform rather than just its level. They are the general-purpose characterisation tool of an RF or communications bench, used where someone needs to measure modulation quality, spurious content or the detail of a signal that a simpler meter would miss. The distinction from a spectrum analyser is one of emphasis: a signal analyser is built to decode and quantify what a signal is carrying, not only to show where energy sits across a band, though the two capabilities increasingly live in the same box.

Spectrum analysers

Spectrum analysers display signal power against frequency, so the operator sees at a glance what is present across a band and at what level. This is the classic instrument for finding interference, checking that a transmitter stays inside its allocation, or confirming that a circuit is not radiating where it should be silent. It differs from a signal analyser in intent: the spectrum analyser answers "what is on the air, and how strong", where the signal analyser goes on to ask "and what is it saying". Only a small number are listed in this category, which tends to place them toward the upper end of the price range when they do appear.