USB1208FS DA Out for 180 Hz sinewave?

Hardware
1

I was trying to send out a 180 Hz sine wave from the DA Out 1 at 1800 sps using DaqAOutScan() function. The sine wave was generated in Matlab and showed correctly on the computer screen. The signal measured between pins #13 and #15 on the oscilloscope showed the correct amplitude between 0~5V. However, the signal looked like jumpy dots. Did it mean that the DAC in the USB1208FS did not contain a low pass filter?

Any experience with it would be greatly appreciated.

OS: Win 7
PTB: 3.0.13
Matlab: 2017b
Test code:

DaqIdx = DaqFind;

%% parameters for the sinewave
sineF0 = 180; % Hz
sampRate = 1800; % Hz - help DaqAOutScan on the DA sample rate
sineDur = 60; % seconds
vSine = sin(2pisineF0*[1:sineDur*sampRate]/sampRate);
vSine = (vSine+1)/2;
vSine = vSine’;

tTick = [1:length(vSine)]/sampRate;
figure, plot(tTick, vSine);

options.FirstChannel = 0;
options.lastChannel = 0;
options.f = sampRate;
options.trigger = 0;
options.getReports = 0;
options.print = 0;

params = DaqAOutScan(DaqIdx, vSine, options);

cznel

2

Code looks ok. I would assume that the DAQ wouldn’t have a low-pass filter (also how would the filter know where the low-pass frequency should be, given each use case would need different limits?), so that could explain “steppyness” instead of smooth curves, but certainly the manual it came with would tell you?