TRANSFER DATA TO PC VIA A GPIB BUS

[conchita]

Hi there.

I am trying to control a Agilient E4448A spectrum Analyser using a GPIB. I am able to set all the parameters (ie: start, stop, centre  frequencies....). I am able to save data in a .csv file that i can save to a flopy and tranfere to the computer. Now i am trying to find a way to transfer the data directly from the spectrum analyser to the PC via the gpib bus.

The documentation has the commands :FORM ASCII REAL,32 which gives the data in in ASCii format. And then it talks about TRAC:DATA? TRACE1 which return the current values of the trace.

and then it talks anout DEFINATE LENGTH BLOCK DATA. From what i understand the data has to be coverted in to this form before it can be transfered via the gpib bus. I am quite new to this and don't really know in what order thses commands are meant to be used if they are all meant to be used together and also if i need to first save the file in the spectrum analyser using :MMEM:STOR:TRAC command before transfering the data.

Can somebody please help?? Thanx in advance..

[Dennis_Knutson]

Why aren't you using one of the drivers?

[conchita]

I did look at the driver but there was nothing in the driver that lets me transfer files straight to the PC via the GPIB bus..

[JÞB]

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I am trying to find a way to transfer the data directly from the spectrum analyser to the PC via the gpib bus.

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OK, a few basics on Spec annies. (Feel free to browse a few web sites as well ... and read a whitepapers or seven. 😉 )

there are two basic type:

A "Real-Time" SA has a high speed digitizer on the front end that feeds a DSP (Digital Signal Processor) The DSP does some funky math (Forrier Transform) on the incoming Voltage vs Time waveform and converts it to Frequency (and phase) vs Power. Both the DSP input and output are digital representations of the original analog waveform so the errors stack up from the processes but you only need a small slice of time to acquire the original sample. On this type of instrument you can usually transfer both the digital V vs T and the F(P)- vs P data.

E series SA's are the analog type. Essentially they operate by tuning a power meter from the lowest frequency (and band) step by step up to the highest frequency and band selected. The "Step size" determines the bandwidth of each step and a mathematician named Nyquist describes how long each step must take. That means you NEVER know the power at any two steps at the same time but, you know the power at a step at a time accurately. The frequency vs power plot takes a variable amount of time to learn so this type to SA stores the plot in some form (like a buffer) each time the sweep starts the buffer is overwritten so you have to save a whole sweep to another location before transferring it (like a floppy or internal memory)

T he idea of "streaming data" cannot be applied to a waveform that is outside of the "Time Domain" and as I said, "Time" does not exist definitively in analog SA's (the output is Freq v Power no time dimension in the vector).

All that being said I probably confused you more than I intended but, the solution remains: "Read the manual to learn how to store the SA sweep to memory" then "transfer from memory." And, you cannot "Stream data in real time" without a different class of instrument.