我们也确实有很多客户的PCB要进厂（我们也是一家装配公司），所以我们希望在收货的过程中也进行这种测试（只要有可能）- - 因此，成本不是唯一的问题，还有可用性和灵活性。因此，我对可供选择的方案感兴趣，以获得大格局的建议。谢谢 :)
TDR Device parameters
We are currently intending to purchase a TDR device (or maybe 2) to measure the impedances of various traces on PCBs but we are just at the beginning. Can you recommend some good devices or devices which are commonly used in the industry at the moment? What are the parameters I have to look at (I know that the rise time is the most critical one; but what else characterizes such a system)?
Thanks for your info. We (in fact) are "PCB guys" but we intend to transition to high speed designs (Gbps range) and since I hate relying on the fab guys telling me what they measured, I would like to perform these measurements by myself (just to be sure the design is in fact correct). As always: measuring is better than just guessing.
We also do have quite a lot of customer PCBs going in (we're an assembly company as well) so we would like to do this testing also in the process of receiving goods (whenever possible) - therefore the cost is not the only issue, but also usability and flexibility. Therefore I was interested in the options available to get the big picture. Thanks :)
Are you just making pcbs and want to measure the impedance at 1Mhz? If so I think there are some cheaper boxes that will work but I've never used them.
If you're doing high speed engineering work the sparq is awesome. It's a TDR and a s-param extractor, like a network analyzer but easier to use and built for pcb guys.
I've also used the tek sampling scope with TDR option.
The main thing I'd look for would be edge speed of the test signal, the faster it is the more detail you're going to see. After that software and what it can extract for you. Oh and probing both these tools are SMA input and output which means your test card should have SMA connectors on it.
If it doesn't take a look at gigaprobes extremely highspeed probes for use with the above kind of TDRs (or scopes). I've used them to get s-param and impedance measurements for motherboards from the intel processor connector down the pci-e pins.
Consider a Vector Network Analyser with the time domain option.
Frequency domain is the new Time Domain, at least according to Agilent / Keysight. It plots eye diagrams, measures length, impedance, mismatch...
But seriously, for measuring trace impedance, a network analyser is a good choice of instrument.
I found the Lecroy and giga guys very knowledgable and willing to help, but none of the above is cheap!