Interversus
New member
Hi,
I am about to embark on a project and I came across this forum which looks like a wonderful way to tap into the experience of others who have gone before me. I have very little experience with what I am about to attempt, and any guidance, warning and nudges are very welcome. I've got a teensy 3.2 to play with.
I want to make a 2 channel data logger for two analogue signals. I need to create a system to do this pretty much "as fast as I can". If I can do this at for a ~5 KHz signal it will be useful for me, 1MHz will have nailed it.
The 2 channels are I and Q data, so I need to sample them synchronously (or close enough for me to make a decision on the accuracy of the sample).
Amplitude, I can scale my input for the teensy no problem, I can tolerate some ADC noise as long as I can quantify it. 12 bit sampling should be fine, 16 bits are perfect. 8 bits is a bit low but I'd consider it to gain significant speed.
My first question is to all the people who have constructed high speed ADC routines, memory writing code, USB transmission, SD card streaming etc, and it is; what methods do you use to test the timing of your creations? Do you time stamp code, or do you get the scope out and toggle pins to measure achievable times? Any tips on how to measure and debug time is going to help me.
Question 2:
Anyone got a good plan or tips on how to tackle 2 channel synchronous sampling at high speed. The teensy 3.2 has 2 ADC's? Can they be triggered with the same interrupt, and has anyone got experience with this?
Question 3:
Ideally I would love to sample two channels at 1Msps and store the whole lot continuously to harddrive for hours. How far removed from reality is this dream? If I can get 1% of this speed, it might still be worth me trying, but 0.1% then I'm going to have to think of ways around the bottlenecks.
I've trawled for commercial solutions, but they all stop short at the "hard drive logging" bottle neck. Picoscope say it should be possible if I write the code myself, but I thought I'd try the teensy first as I have control of everything, just not the knowledge of how to estimate what is achievable yet!
thanks in advance for any input to any part of the above,
I am about to embark on a project and I came across this forum which looks like a wonderful way to tap into the experience of others who have gone before me. I have very little experience with what I am about to attempt, and any guidance, warning and nudges are very welcome. I've got a teensy 3.2 to play with.
I want to make a 2 channel data logger for two analogue signals. I need to create a system to do this pretty much "as fast as I can". If I can do this at for a ~5 KHz signal it will be useful for me, 1MHz will have nailed it.
The 2 channels are I and Q data, so I need to sample them synchronously (or close enough for me to make a decision on the accuracy of the sample).
Amplitude, I can scale my input for the teensy no problem, I can tolerate some ADC noise as long as I can quantify it. 12 bit sampling should be fine, 16 bits are perfect. 8 bits is a bit low but I'd consider it to gain significant speed.
My first question is to all the people who have constructed high speed ADC routines, memory writing code, USB transmission, SD card streaming etc, and it is; what methods do you use to test the timing of your creations? Do you time stamp code, or do you get the scope out and toggle pins to measure achievable times? Any tips on how to measure and debug time is going to help me.
Question 2:
Anyone got a good plan or tips on how to tackle 2 channel synchronous sampling at high speed. The teensy 3.2 has 2 ADC's? Can they be triggered with the same interrupt, and has anyone got experience with this?
Question 3:
Ideally I would love to sample two channels at 1Msps and store the whole lot continuously to harddrive for hours. How far removed from reality is this dream? If I can get 1% of this speed, it might still be worth me trying, but 0.1% then I'm going to have to think of ways around the bottlenecks.
I've trawled for commercial solutions, but they all stop short at the "hard drive logging" bottle neck. Picoscope say it should be possible if I write the code myself, but I thought I'd try the teensy first as I have control of everything, just not the knowledge of how to estimate what is achievable yet!
thanks in advance for any input to any part of the above,