When you're choosing between an oscilloscope, signal generator, and spectrum analyzer for your bench, you're really comparing two philosophies: a multi-tool that does a bit of everything, versus a specialized instrument that focuses on one job. That's exactly the choice between the FNIRSI DPOS350P and the Agilent N9320B. One costs $225 and bundles several test functions into a single open-box unit; the other costs $1,200 and is a used, dedicated RF spectrum analyzer from Agilent. The right pick depends on whether you need wide RF frequency coverage or a more versatile signal workhorse. Both are legitimate options, but they serve different workflows.
Quick verdict
Choose the FNIRSI DPOS350P if you want a single instrument that combines a two-channel oscilloscope, signal generator, and spectrum analyzer at a far lower price than the Agilent. Choose the Agilent N9320B if your work is devoted to RF spectral analysis and you're prepared to deal with a used, as-is unit.
Comparison table
| FNIRSI DPOS350P | Agilent N9320B | |
|---|---|---|
| Price | USD 225.00 | USD 1,200.00 |
| Price bar | ||
| Condition | New - Open box | Used |
| Tool type | 4-in-1: oscilloscope, signal generator, spectrum analyzer | Dedicated RF spectrum analyzer |
| Spec highlights | 350MHz two-channel scope, 1GSa/s sampling | 9kHz-3GHz RF range, -130 dBm noise floor |
Where each product wins
The FNIRSI DPOS350P wins on versatility. It packs a two-channel oscilloscope, a signal generator, and a spectrum analyzer into one unit, with a 7-inch 1024x600 display and a waveform capture rate of up to 50,000 frames per second. You get a full bench setup in a single purchase for far less than the Agilent. The Agilent N9320B wins on focus. It is a dedicated RF spectrum analyzer, not a general-purpose tool, so its design and specifications center entirely on RF signal analysis. For anyone whose work revolves around radio-frequency measurements, that specialization is worth the added cost.
Product notes
FNIRSI DPOS350P 4-in-1 Digital Oscilloscope
The DPOS350P is a 4-in-1 instrument: a two-channel oscilloscope with 350MHz bandwidth, a signal generator, and a spectrum analyzer. Its 1GSa/s real-time sampling rate and 50,000 waveform captures per second make it well suited for examining high-speed digital and analog signals. The 7-inch screen with 1024x600 resolution gives you a clear view of the waveforms and measurements. With 12 types of parameter measurements and ±400V overvoltage protection, it covers a wide range of general electronics diagnostics. The main trade-off is that it's an open-box item, and as a multi-tool it doesn't offer the dedicated RF specifications an advanced RF engineer may want. If you need a complete bench set in one unit, this is the convenient path.
Agilent N9320B RF Spectrum Analyzer
The N9320B is a professional-grade RF spectrum analyzer covering 9kHz to 3GHz, with a displayed average noise level of -130 dBm. Its resolution bandwidth and video bandwidth both span 10Hz to 1MHz, giving you very fine spectral detail for radio-frequency troubleshooting and lab work. This is a dedicated instrument, not a multi-tool, so you get specifications tailored specifically to RF analysis. The catch is the condition: it's a used unit, out of calibration, and sold as-is with no accessories or power cable. If you already have a power cable and can work with uncalibrated measurements, the N9320B offers serious RF frequency coverage for the price. For RF work, that level of detail is essential.
Final choice by use case
For a general electronics workbench where you need to see waveforms, generate test signals, and do occasional spectral checks, the FNIRSI DPOS350P gives you the most capability for a single purchase. If you need one tool that handles many jobs, it's the natural fit. For an RF-focused workshop or laboratory that requires a dedicated RF spectrum analyzer, the Agilent N9320B is the more appropriate choice if you can work with an out-of-calibration instrument. That specialization explains the higher price.
