How do I extract the 32Mpts from U270xA?

One way of “viewing” the full memory waveform is using the zoom function (that the red arrow is pointing to in the attached picture below) at the top when you stop the acquisition. This method allows you to see the full memory waveform qualitatively. You will be able to pan left and right to view the waveform.

Another way to view the save your raw ADC data in binary (.bin) format:
To save your data, go to File > Oscilloscope, and then select the desired save format as shown in the File menu below.

Sample Program for Binary Data Conversion
This sample program will help you convert the binary data (*.bin file) extracted from USB modular oscilloscope, to actual amplitude values. Sample Program for Binary Data Conversion

Another way to view the full data if the customer desires to program the scope is to use the following commands.
In case you are not aware, we have a full range of programming guides and examples (along with other useful technical materials) that can be downloaded at the following website.
www.keysight.com/find/usbtechoffer

In particular, please use the following command if you would like to read back the full memory depth
IKeysightU2701A.Measurements.Item(“Channel1”).ReadFullWaveform

And please use the following command if you would like to read back 1250 points.
IKeysightU2701AMeasurements.Item(“Channel1”).ReadWaveform is for single acquisition.

The 1250 points that you have seen is due to a pre-set designed to have a faster refresh rate. However, all the full memory are stored inside the circular buffer and can be accessed.