Why do sampling rate change automatically ?

Dear Sir or Madam,

I would like to get PRBS data ( 1 Mbps ) for 10 MSa/s sample rate. But, when I tried to get data from oscillscope for 10 MSa/s , the data had changed 100 MSa/s on osiclloscope.

I think that some command may change the sample rate.

So, I show you program that is for getting data.

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myScope = oscilloscope();
availableResources = getResources(myScope);
myScope.Resource =  'USB0::0x0699::0x0368::C024169::0::INSTR';
% Connect to the instrument.
connect(myScope);
get(myScope);
% Automatically configuring the instrument based on the input signal.
autoSetup(myScope);

myScope.TriggerMode = 'normal';

myScope.TriggerLevel = 0.01;

enableChannel(myScope, 'CH1');

setVerticalCoupling (myScope, 'CH1', 'AC');

setVerticalRange (myScope, 'CH1',5.0);

waveformArray = getWaveform(myScope, 'acquisition', true);

% Plot the waveform.
plot(waveformArray);
xlabel('Sample');
ylabel('Voltage[V]');
disconnect(myScope);
clear myScope;

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I'm glad if you let me know.

Sincerely,