Electronic – Homebrew differential ‘scope probe

I would certainly be interested in this. Particular things that would appeal to me:

1. Isolation from PC and from other channels
2. Multiple synchronised channels
3. Polished cross-platform interface software
4. Cheaper than the competition: the other self-contained units such as the handheld picoscopes.

I've used quite a few USB scopes, but the (single- and dual-channel) picoscopes trump the rest simply on the software at the moment.

To be honest, personally I'm not that bothered by the self-contained thing or the unpowered hub thing. If I could find some good, cost-effective, multi-channel USB scopes that worked on any platform, had good software, reasonable specs and isolation between the channels, I'd be over the moon.

500kHz is a ways past the maximum specified frequency for square waves for this generator: 100kHz. It appears to have a single-pole RC of about 3.5µs, which would work great for a 0.35/(3.5µs)=100kHz square wave. The output may have a LPF for slew limiting. Also, it is a 50Ω source, so it should be terminated properly to avoid ringing. Try using the TTL and CMOS waveforms, too. B&K have put together this document: Function & Arbitrary Waveform Generator Guidebook .

The external CMOS inverter is not a 50Ω source -- it's source impedance is only a few ohms at most (for low currents) due to V_CC and ground impedances and FET R_ON equivalent resistances. Notice that the output duty cycle isn't 50%, and the edges are ringing.