aloishis89
Junior Member level 2
I'd like to measure propagation delay through a chip. This is often on the order of 5-7 ns, and I'd like to be able to sense down to a nanosecond or less so I can get good accuracy. Here's the approach I'm thinking: https://i.imgur.com/Tnksf.png
I'm interested in measuring delay through a logic chip (this whole project is for a demonstration) so in the schematic there, I would send a pulse to one input of the AND gate, and the output goes through a bunch of flip flops, where each stage slows down the pulse by half. Then by the time it gets to the end, the pulse is slow enough to read in a microcontroller. The problem is, this requires knowing the propagation delay of the flip flops really accurately. I know that some PICs have a feature that let you measure really fast events, and the other method I know of involves charging a capacitor and reading how much it's charged to see how long the pulse was. I'm not sure how accurate the capacitor method is, and I'd like to use the flip flop version over the PIC version for demonstration purposes if possible. What's the best approach for this?
I'm interested in measuring delay through a logic chip (this whole project is for a demonstration) so in the schematic there, I would send a pulse to one input of the AND gate, and the output goes through a bunch of flip flops, where each stage slows down the pulse by half. Then by the time it gets to the end, the pulse is slow enough to read in a microcontroller. The problem is, this requires knowing the propagation delay of the flip flops really accurately. I know that some PICs have a feature that let you measure really fast events, and the other method I know of involves charging a capacitor and reading how much it's charged to see how long the pulse was. I'm not sure how accurate the capacitor method is, and I'd like to use the flip flop version over the PIC version for demonstration purposes if possible. What's the best approach for this?