OWON XSA1000P Series

Resolution bandwidth (RBW) is the width of the analyser’s internal filter as it steps across the span. It decides how close together two signals can be and still appear as two peaks rather than one hump.

A narrow RBW separates crowded signals and lowers the noise floor, because less noise power falls inside the filter — roughly 10 dB for every factor of ten. The cost is sweep time: halving the RBW makes the sweep about four times longer, so you choose the widest filter that still resolves what you need.

In practice: Looking for a spurious emission 15 kHz away from a strong carrier: at 10 kHz RBW it hides inside the carrier’s skirt. Drop to 1 kHz and it separates cleanly, and the noise floor falls about 10 dB with it.

EMI pre-compliance mode swaps the normal measurement bandwidths for the CISPR-defined ones — 200 Hz, 9 kHz, 120 kHz and 1 MHz at −6 dB — and adds stored limit lines to test against.

A formal EMC test house charges by the day and books weeks ahead. Finding a failing harmonic on your own bench first, with the same bandwidths and the same limit lines the lab will use, turns a failed booking into an afternoon of filtering.

In practice: A switch-mode supply radiating at 150 MHz shows 6 dB over the EN 55032 Class B line. You add a common-mode choke and re-scan against the stored template until it passes, before booking the chamber.

A spectrogram (waterfall) plots frequency horizontally and time vertically, with colour showing amplitude — so you watch a band change over seconds or minutes instead of seeing only the instant the sweep passed.

A single sweep shows what was there at that moment. Signals that hop, burst or appear intermittently are invisible to it far more often than not. The waterfall turns "it happens sometimes" into a pattern you can point at and time.

In practice: An intermittent 2.4 GHz dropout: the waterfall shows a wideband burst repeating every few seconds, its timing matching a nearby machine’s duty cycle — which a single sweep would only catch by luck.

LAN, USB and the SCPI command set let the instrument be driven from a PC, and its screen and data pulled off it, without anyone standing at the front panel.

Anything you do twice you will do a hundred times. SCPI over LXI, USBTMC or a raw socket means a test sequence runs unattended and logs to file, and LabVIEW or IVI drivers drop it into a rig you already have.

In practice: A production check that sweeps five bands, compares each against a limit line and writes pass/fail to CSV — the operator presses one key instead of setting the analyser up five times per unit.