PI Question

[lucifer]

Hi Carl,
in the second edition of ITMD you mention that the decay response at turn-off is purely resistive which I understand and that's what makes discrimination difficult if not impossible. You also mentioned that if response is sampled at turn-on, it contains also a reactive component. What's the physics behind that? How does it come that the reactive response is present at turn-on only?

[Carl-NC]

During the TX pulse the coil current is constantly changing (rising exponential) and this generates both reactive and resistive responses. You also get a reactive response during the turn-off transition, up to the point where the coil current dies out.

[lucifer]

Got it, thank you.

[heejnn]

在发射脉冲期间，线圈电流不断变化（呈指数上升），这会产生电抗和电阻响应。在关断过渡期间，直到线圈电流 消失，你也会得到电抗响应。

谢谢

[Qiaozhi]

谢谢

I know that you said "thank you" (Xìexie), but please make your posts in English as per the forum rules.

[ivconic]

quasi shohi doesn't like xiexie! This is good material for Monty Python!
It's late, I'm tired... I'll see what Mr. Cleese has to say on this topic one of these days!

[Carl-NC]

During the TX pulse the coil current is constantly changing (rising exponential) and this generates both reactive and resistive responses. You also get a reactive response during the turn-off transition, up to the point where the coil current dies out.

Browsing through old posts... I should have also said that in order to see the reactive turn-on response, you need to use an IB coil. Mono won't work.