Signal Generator Frequency Restrictions (PS5444D)

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dfergenson
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Signal Generator Frequency Restrictions (PS5444D)

Post by dfergenson »

I'm writing some VB.net code to control the function generator on my PS5444D and I've run into something that I'm not sure is fully documented.

ps5000aSetSigGenBuiltIn is described on P. 102 of the API Programmer's Guide and it refers to the minimum value of the argument startFrequency as being PS5000A_MIN_FREQUENCY but I couldn't find a definition of this value in the manual or example code.

Similarly, the max frequency values for the different wave types didn't appear to be defined:
PS5000A_SINE_MAX_FREQUENCY
PS5000A_SQUARE_MAX_FREQUENCY
PS5000A_TRIANGLE_MAX_FREQUENCY
PS5000A_SINC_MAX_FREQUENCY
PS5000A_RAMP_MAX_FREQUENCY
PS5000A_HALF_SINE_MAX_FREQUENCY
PS5000A_GAUSSIAN_MAX_FREQUENCY

Am I missing the information somewhere? Perhaps someone can correct me and point me towards where I would be able to find it or, otherwise, perhaps Pico can let me know what frequencies I should govern these values to?

Otherwise, I'll see if I can find these minimums using binary searches and will post my results to this thread.

-Davio

hexamer
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Re: Signal Generator Frequency Restrictions (PS5444D)

Post by hexamer »

Here is the macro from the C header file:

#define PS5000A_MIN_FREQUENCY 0.03f

To be exact, you can compute what it should be by also taking a clue from the other macros that encode DDS/DAC frequency and phase accumulator size.

#define PS5000D_DDS_FREQUENCY 100e6
#define AWG_PHASE_ACCUMULATOR 4294967296.0

The actual minimum should be 100e6 / 2^32, or 0.023283064365386962890625

But, I would check to see if the API will accept values < 0.03. I've seen cases where even though the DDS parameters will suggest a lower values is possible, the driver will refuse to accept it.

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