Author Topic: DS1074Z-S signal source arb questions...  (Read 1410 times)

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Online alank2

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DS1074Z-S signal source arb questions...
« on: October 09, 2015, 01:32:56 PM »
Hi Everyone,

I've been playing around with the ultra station software (it is NOT impressive).  If I make a new file for DS1074Z-S and set it to the maximum speed (10MHz), it will let me freehand a waveform.  I saved it to a RAF file which if I am understanding right, is the same thing as an ARB file and can be loaded on the scope.

My first question is, can it really play 16384 points at 10Mhz?  It suggests that this is the case when I right click and switch from points (showing 16384) to time showing 99.994n.  If this is true, HOW does it accomplish this?

Second, can someone make a sample small number of points ARB file and post it.  The file is a raw 16K file storing 16 bit integers.  I wonder if you only put say 4 points in, does it will 4K with point 0, 4K with point 1, 4K with point 2, and finally 4K with point 3?

Thanks!
 

Online alank2

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Re: DS1074Z-S signal source arb questions...
« Reply #1 on: October 09, 2015, 11:14:17 PM »
Well...  This page suggests something different:

http://www.bkprecision.com/support/downloads/function-and-arbitrary-waveform-generator-guidebook.html

Basically that it can only play points at the sample rate it it is rated for.

Given this, why does the Rigol software show 16384 points across one cycle of the selected frequency?  Does that make any sense?  Also, how does the set frequency then relate to the points in the arb signal?  If you select "10MHz" (the max) does it play the points at 200MSA/s (the max)?
 

Online alank2

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Re: DS1074Z-S signal source arb questions...
« Reply #2 on: October 10, 2015, 01:03:03 AM »
Still thinking out loud here, if you understand how these things work, please chime in!

Is the DAC always running at the maximum speed?  In this case 200MSa/s.

Does the 16K points ALWAYS represent one cycle, then does it work like this:

If you set it for 10 Mhz, you have 20 samples you can produce when running at 200MSa/s.  If you have 16384 samples in a single cycle, and you can only run 20 points through the DAC, then it must skip ahead 819.2 samples each time.  Is this how it works?
 

Online alank2

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Re: DS1074Z-S signal source arb questions...
« Reply #3 on: October 10, 2015, 08:09:28 AM »
Somebody has to know this!

I've done a lot of forum searching and I saw a couple of people mention making a tool to convert CSV to the raw ARB file that the RIGOL uses.  I'm going to whip up a tool like this that will do two thiings - (1) Convert CSV to ARB.  You can specify the amplitude/offset and it will parse a CSV file and convert the floating point voltage values to the 14 bit integer that the ARB file needs.  (2) Multiple Clock ARB creator that will build an ARB file with a sine or square wave that you specify the number of waves in the file.  If I understand some of the posts I've read properly, even with the RIGOL set to 10MHz Arbitrary if it is playing back a file with 4 waves in it, you will get 40MHz.
 

Online alank2

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Re: DS1074Z-S signal source arb questions...
« Reply #4 on: October 10, 2015, 03:32:44 PM »
So I've got the tool working pretty well so far.  It will create a raw file (ARB, RAF) compatible with all but the DG1000Z series which I think has a header on it.

Use 16384 for the points (memory) setting for built in gens in the DS1000Z/DS2000 scopes.  Use 4096 for the DG1022.

It can convert a raw CSV/TXT file to the ARB/RAF including scaling the voltages using the amplitude and offset settings.  It will calculate and display the valid range of voltages.  Voltages outside of this range will rail at the highest or lowest 14 bit value.  It will automatically up/down convert a CSV file to the number of points you specify.  For example, the supplied file.csv test file only has 16 points in it.  When you convert it, it will be up converted to the value in the points field.  There is an interpolation check box that can enable interpolation between points in this case that will create a straight line between them, turning it off will create a stair type effect.  There is a small graph window that shows what the waveform looks like.

There is also a tab that creates waveforms, you can make a sinewave or squarewave by specifying the number of cycles you want and the phase.  If I am understanding some of the posts I've read here properly, but can create an arbitrary wave that contains 5 sine waves and then set your gen to 10 MHz and it will output 10*5 or 50 Mhz.  Even in this case the hardware has to be up to the job of being able to properly generate it of course.

Anyway, it is version 1.00, tested on nothing but the ultra station application that Rigol provides.  I ordered a DS1074Z-S but won't have it for awhile to actually try and test this out much.

It will not talk to a scope directly.  It will generate an ARB or RAF file that you can copy to a USB stick and load on the signal gen.

Good luck!
« Last Edit: October 10, 2015, 03:38:57 PM by alank2 »
 

Online alank2

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