Fetching data with high speed by means of an analog trigger infinitely

[Benny1982]

Dear Labview experts,

I am currently setting up the data acquisition of a wind lidar and I am struggling with a principally easy task that I do not get solve. I hope the following explanation of my problem is clear and not too stupid.

I am using the NI-5162 in a Schroff PXIe chassis to sample an atmospheric return signal (e.g. 100 MHz sine wave) with a sample rate of 625 MHz and 8bit resolution. I have to acquire the signal for 100 µs (62500 Samples). The signal should be acquired for each single laser pulse which has a repetition rate of 750 Hz. A sketch of my acquisition scheme is shown below (blue indicates the TTL trigger from the laser and orange the time when the signal should be acquired and fetched):

In order to solve my needs, I programmed a producer/consumer loop as you can find in the attached picture. This was the solution I found in the NI-forum that helps to write large amount of data. And indeed, it works quite well for continuous data fetching.

The acquired data is afterwards stored to the SSD in the consumer loop. This part is working rather well.

However, what I can not manage with all attempts that I tried so far is, to realize the case as described above - triggering each single acquisition by means of an analog TTL trigger, sampling 62500 samples with 625 MHz, writing the data to the SSD and do nothing until the next trigger occurs.

Is there any expert that has an simple/smart idea how I could solve my problem?

Any idea is highly appreciated and will be tested immediately.

Thanks a lot for thinking with me and supporting my research in advance.

All the best,

 Benny

[Henrik_Volkers]

See example 

Fetch more records than available 

Set up a multi record acquisition. Choose  the needed samples , configure the trigger...