Are FNIRSI oscilloscope specs real?
FNIRSI floods the marketplace with tablet and handheld scopes at prices that make a Rigol look extravagant — and headline specs that make it look overpriced. The specs are the catch. This isn't "avoid FNIRSI"; it's "buy one knowing what the number means."
What the measurements say
The 1013D advertises 100 MHz and 1 GSa/s. Elektor's lab review of the near-identical 1014D called the specs "a bit stretched" and found it "barely meets the classical -3 dB criterion"; the EEVblog megathread — thousands of posts — puts the "100 MHz" in scare quotes and lands around a real usable bandwidth of ~25–30 MHz. That's not a defect; it's the gap between a marketing number and a measured one. A signal near the claimed bandwidth shows up heavily attenuated and distorted.
Why the headline is misleading
Real oscilloscope bandwidth is the frequency at which a sine wave is attenuated to -3 dB (about 70% of amplitude), measured under standard conditions. Budget tablet scopes often quote the sample rate, or a best-case figure, as the headline — so a "100 MHz" that's really a 1 GSa/s sampler with a ~25 MHz front end. Same number on the box, entirely different instrument. Established brands (Rigol, Siglent, Keysight) quote the honest -3 dB figure, which is why their "70 MHz" outperforms a FNIRSI "100 MHz."
When a FNIRSI is the right buy
- Pocket waveform-checker: the DSO152 (~$25) is honestly good at "is there a signal here, roughly what shape" — servo/PWM checks, audio, teaching.
- Field multitool: the 2C53T bundles a scope, DMM and signal generator in a handheld — a genuinely handy glovebox instrument.
- Not for: protocol debugging, anything above audio frequencies where the real bandwidth matters, or as your only scope if you're serious about electronics.
The every-new-model warning
FNIRSI ships several new SKUs a year (2C53T, 2D15P, DPOX180H…), and each one earns its own "what are the real specs?" forum thread. The pattern repeats: impressive box, optimistic number. Before buying any specific FNIRSI, search its exact model plus "EEVblog" — the community measures them fast. And if $300 is reachable, a real 12-bit bench scope ends the question permanently.