Plotting ADPCM signals?

[BernieSAIC]

I am trying to read an ADPCM signal and make my own player for this so I can analyze the data.  I tried using the serial visa's with no success.  I am guessing I need some different software for this purpose. 

Do I need the modulation toolkit for this or is there some other way to read this I am missing.

The output signal looks like serial data ranging from +5v to -5v.

Any suggestions, thanks.

[OliviaC]

Hi BernieSAIC,

How are you trying to read this signal? via serial? or through a DAQ card?

[BernieSAIC]

I am reading this through the Rx of the serial com port.  So in essence I just want to monitor this pin and decode the data to a graph.  Right now I can see the waveform using some freeware ADPCM player and it reads it correctly, I just cannot automate it using that software so I need to find a solution with LabVIEW.

[OliviaC]

To see the waveform, do you know what command the freeware sends to retrieve the waveform?

Alternatively, when the freeware obtains the waveform, is there a way to export that data from the freeware? If so, you could use the System Exec VI or Open Application Reference VI to programmatically launch the freeware and export the data from it.

[BernieSAIC]

I tried to find the file it uses to collect data but was unsuccessful.

I have no clue what commands the freeware uses.

I will look further into finding the data file but am also open to other suggestions.  Thanks for the help so far.

[OliviaC]

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BernieSAIC wrote:
I am reading this through the Rx of the serial com port.  So in essence I just want to monitor this pin and decode the data to a graph. 

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Is this signal continuously coming through this pin? or is it sent only when you ask for it?

[BernieSAIC]

When I turn the modulation on on the Signal generator the waveform will start.  Withou tthe modulation on it just reads no signal (noise).

BK

[OliviaC]

Hi BK,

Most times, when you want data from a serial device, you need to query it and then it sends the data. However, it sounds like yours is continuously streaming data (whether it's an actual signal or just noise). NI VISA Read should be able to interpret this data but needs to know certain characteristics about the way the data is sent such as the stop bit and parity bit or else it won't know how to interpret the data it reads. This is the kind of information you should be able to get from the signal generator manual.