Analog sampling, so it begins

Just reading through some tutorials about analog sampling.. Great buzz words for sampling are sampling rate, Nyquist's thereom, quantization, and dithering.

http://zone.ni.com/wv/app/doc/p/id/wv-291

Also, here is what I have been going through today as well:
http://zone.ni.com/devzone/cda/tut/p/id/3405

Quite a lot to learn.

-Kyle

Moving on to Rock -n- Roll Sampling

Alright.. John and I had a good talk with Dr. He today regarding next steps, and a little proof of concept on LEDs.

Next milestone so to speak.. The ultimate goal is to sample a sound card out of a computer.
That has a lot of facets, of which, I need to explore exactly how to do it. Just a sampler of requisites for sampling sound is: For accurate measurements, the sampling rate of the system should be at least twice the frequency of the signals being acquired. Pulled that off the NI website. (http://zone.ni.com/devzone/cda/tut/p/id/7110#toc1)

Then from there, off to photomultipliers, and sampling them, but that would be getting ahead of ourselves. Anyways... I'm off to do some more research on sampling sound. I'm going to start on the above link, and follow the proverbial rabbit hole.

-Kyle

Kyle University

http://www.ni.com/swf/presentation/us/labview/lvfpga/default.htm

Okay, I am showing john this great presentation, the first part of it is pretty useless, but once you get down to the demos it has some real juicy information. We went through this presentation with lots of stops to show nuances within labview, and the subtle differences that a labview operator is aware of.

Friday......

Boy is it hot outside... Glad to get inside, and cooled down.

Haven't made a lot of show able progress today, but I've been going through a lot of FPGA documentation on the Developer Zone on NI's website. Learning a bit more about DMA FIFO memory access, as well as using interrupts. Basically... You compile an FPGA VI to get a specified amount of data from a channel, let's say.. Collect 5 analog samples of a temperature sensor, when it has 5 samples, the FPGA VI, sends it up to the Host VI. Host VI then says, okay, this temperature is out of spec, let's compare it to the last couple values. Okay, it has been out of spec for 6 cycles, therefore, I want to open the cooling valve by Pi()/64 radians, which sends this procedure to a sub-VI that opens the cooling valve a little bit. Once that Sub-VI is done, it goes back to the Host VI, and says, ok, I'm done. The Host VI says, okay, in order for the system to return to steady state from the transient state I just put it in, I need to wait 40 seconds. So... Wait 40 seconds... Then, go back to FPGA VI, and take more samples.. Repeat...

Makes sense to me...

-Kyle

Okay, so the digital LED went well.... but....

I have struggled a bit after getting the digital LED thing going... I thought I was going to jump right into other stuff... As the day wound down, I ended up going with an analog LED VI.. Right around 1.8 volts the LED starts to come on, but is very dim.. After 2 volts, it doesn't really get any brighter, and the rail is like 16volts..

Anyways, here is the VI for it.

Tada........

Well... Here it is.. Wish I had a video camera to show you, but this is the blinking LED. I put it so it is logic 1 for 500ms, and logic 0 for 500ms, so it blinks on and off once per second.. I thought about going through gyrations of speeding up the blinking light, and slowing it down, or even putting it on a random number generator, but I think I got the premise down, and time to move on to bigger and better things.

Let's see about doing a little digital input!

-Kyle

Another week goes by, and progress it is!!!!

This is what I go so far.. It makes the LED blink on and off like I want, but not at the rate at which I want... I did notice though that when you pull the digital output to ground on the multi-meter, that the voltage is not the logic 5v I expected, but right at the point where its leading edge is high enough to push it into the 1 slot,, 3.2 volts or whatever...

-Kyle