MATLAB does not read the data correct from the Oscilloscope

Hi there,

Recently I have had issues with the binblockread function in matlab.

I am trying to read a waveform from a oscilloscope, I can clearly see the waveform on matlab, however the voltage

values are printed incorrect. I am using an int8 for the precision.

I was wondering is there any scale conversion exist here that I am unware of?

I would highlty appreciate some help on this,

Thank you very much

Nikan

[Cristhian Zárate]

Hi Nikan,

Usually, in the programming manual, you have the documentation of how to read the data from the instrument.

For example:

" The read data consists of two parts - TMC header and data packet, like #900000ddddXXXX..., among

which, “dddd” reflects the length of the valid data packet in the data stream, “XXXX...” indicates the data

from the data packet, every 2 bytes forms one effective data, to be 16-bit signed integer data "

Assuming you alread read the preamble, next you read the data

adc8bit_data = binblockread(scope_obj, 'int16');

Then, you process the adc data as found in the manual...

i). the channel voltage -

channel voltage = ( channel ADC data / 6400 - channel zero offset) * channel volt scale

Note: ADC Data = waveform data, or Vmax, or Vmin, or Vavg (16-bit signed integer data)

In case you don't have any information use the following walk-around

Find the value of "factor" until you get what you see in your oscilloscope screen. You can do it so by applying a 1Vpp sine waveforme.

waveform_data = (adc8bit_data/factor - vertical_offset)*vertical_scale

It would helpfull to know the brand and model of your oscilloscope.

Cris