Mixed Signal Oscilloscope Buying Guide
Specs, Models, and Used vs New

Match the instrument to the job, not the brochure.  Start with the fastest signal and the buses you actually need to probe, then focus on the specs that the job requires.

In automotive and EV work, CAN FD bus debug needs the 16 digital channels and CAN FD decode,  while LIN and SENT sensor work may require additional decode options. Automotive Ethernet and EV inverter gate-drive analysis can push you toward higher bandwidth and 4 analog channels for phase-current correlation. For worked examples, see the guide to automotive oscilloscopes and Keysight automotive oscilloscope models. For a deeper application walk-through, see the planned automotive diagnostic oscilloscope guide once it is available.

In aerospace and defense, MIL-STD-1553 and ARINC 429 monitoring may require the matching decode options, plus deep memory for longer captures such as DO-160 power-rail pre-checks. Redundant-bus failover and multi-rail sequencing checks often rely on the digital channels to capture multiple discrete lines at once.  Two related guides are planned: a DO-160 pre-compliance guide and a MIL-STD-1553 bus debug guide.

In embedded and power electronics, DDR command timing, multi-rail sequencing, and GaN or SiC switching-node analysis can require digital channels, high vertical resolution, and a high sample rate. Deep memory matters here because intermittent faults and long serial frames  may need longer capture time at a high sample rate.

Used inventory rotates, so a close configuration can often be upgraded to meet the requirement. Availability changes as instruments are purchased and new units are listed. If the exact model is unavailable, check whether a nearby configuration supports the capability you need:

• Some DSOX models can be upgraded with MSO capability after purchase through a software license plus the matching digital-channel probe kit.
• Bandwidth on many MSOX and DSOX models can be upgraded after purchase, within the limits of the specific platform.
• An MSOX model generally includes the analog capabilities of the corresponding DSOX model and adds digital channels, so it can be a practical alternative when the DSOX configuration you wanted is unavailable.

These paths can help you meet the measurement requirement without waiting for the same configuration to return. Supported options vary by model, current configuration, bandwidth, and platform, and the required software license or probe kit may be separate from the listed instrument. Check model-specific details, including the installed options and supported upgrade ceiling, rather than relying on a series name alone.

Confirm the upgrade path on the product page before you order, create an account for price alerts, or tell us your application and we will match an available MSO when you request a quote.

A few common buying mistakes can cost engineers time and budget.  Avoid these, and the rest of the buying process gets easier.

• Under-buying bandwidth: a scope sized to your current clock leaves no margin for the next project, so size bandwidth to about 5x the fastest clock you expect to see.
• Ignoring memory depth: a high sample rate can drop quickly  on a long capture if the memory is shallow, which hides intermittent faults.
• Forgetting decode licenses: serial decode for CAN, I2C, SPI, and USB is often a separate option, so confirm it is enabled on the exact unit.
• Mismatched probes: a probe with less bandwidth than the scope limits the bandwidth you paid for, so match probes to the instrument.
• Buying an MDO when an MSO fits: the RF domain adds cost you may not use, so choose it only when you need spectrum analysis.
   

It is reasonable to question a used instrument purchase, so let’s answer the concern directly. The concern is usually about reliability, calibration, and support, not price. The price case is strong: certified used instruments can save 40 to 90% versus new. The risk side is what you should weigh next.

Consider the cost of getting it wrong. A Keysight-commissioned survey of 305 test engineers, found that more than 90% of companies reported revenue loss because of preventable equipment-related delays and 53% reported $100,000 or more of waste per day while waiting to resolve critical issues. Electronic Specifier's independent industry coverage also reported the survey findings. That reframes the decision: paying less up front can quickly cost much more if the instrument fails on a deadline or lacks support. Used equipment also has a sustainability case. The UN's 2024 Global E-waste Monitor reports a record 62 million tonnes of e-waste in 2022, with only 22.3% formally recycled, so OEM-recertified used gear extends equipment life and cuts waste. Before you compare on price alone, read why a low-priced scope can cost more.

Not all "used" equipment is equal, and the source matters. Keysight certified used instruments are inspected and tested by the OEM before sale. Calibration is as listed on each unit, with a fresh Keysight calibration option where offered. Up to 5 years warranty options and KeysightCare technical support are available as options, and software and hardware customization is available on request.

Keysight Premium Used is the higher tier. Each instrument is OEM-refurbished (at the same site where new Keysight equipment is manufactured), passes a final 101-point quality inspection covering function, performance, and condition, and ships with the same firmware, software, accessories, customization options, and warranty as new. The difference from broker refurbishment is the OEM behind the work.

Calibration should mean more than a sticker on the instrument. NIST defines metrological traceability as a result linked to a reference through a documented, unbroken chain of calibrations, each contributing to the measurement uncertainty. That is the kind of traceable calibration record a credible certified-used instrument should provide. For the full picture, see the used oscilloscope buying guide hub.

Buying direct from the manufacturer changes the risk profile. You get OEM calibration and customization, warranty options, and a support team you can reach, instead of a broker and a hope. For procurement, that also means a known supplier path, clearer lifecycle and end-of-support information, and in-stock equipment that may ship faster than a new-build order. For the engineer, it means the model arrives ready for the job, with decode and software options confirmed rather than assumed. Used test equipment bought direct from the OEM does not have to be a compromise. It keeps the savings and removes the parts of "used" that engineers and procurement actually fear: the stigma, the broker roulette, and the missing support. Second-Hand. First-Class.

Choose  your MSO in four steps: confirm you need digital channels (MSO, not just a DSO), size bandwidth and sample rate to your fastest clock, choose channel count and memory depth for your buses, and compare used versus new based on total cost. Buying used direct from the OEM gives you OEM quality, warranty options, and support at a used price. Browse certified used inventory and request a quote.