# USB1208FS DA Out for 180 Hz sinewave?

**URL:** <https://psychtoolbox.discourse.group/t/usb1208fs-da-out-for-180-hz-sinewave/3691>\
**Category:** Hardware\
**Created:** [February 21, 2021, 7:31am UTC](https://psychtoolbox.discourse.group/t/usb1208fs-da-out-for-180-hz-sinewave/3691 "2021-02-21T07:31:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![czne](https://avatars.discourse-cdn.com/v4/letter/c/a88e4f/32.png) [@czne](https://psychtoolbox.discourse.group/u/czne)\
**Post date:** [February 21, 2021, 7:31am UTC](https://psychtoolbox.discourse.group/t/usb1208fs-da-out-for-180-hz-sinewave/3691/1 "2021-02-21T07:31:16Z")

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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(2_pi_sineF0\*[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

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<div class="post-metadata">

**Author:** ![mariokleiner](https://avatars.discourse-cdn.com/v4/letter/m/13edae/32.png) [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\
**Post date:** [February 23, 2021, 3:42am UTC](https://psychtoolbox.discourse.group/t/usb1208fs-da-out-for-180-hz-sinewave/3691/2 "2021-02-23T03:42:47Z")

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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?