Newbie questions

[Pete]

Good Morning
First post so be gentle , I am slowly trying to learn about electronics and adequate measurements. I bought Pro version while ago mainly to help me with turntable and cartridge setup but I’d like to learn bit more about , so far I have used built in measurements but I bought function generator and oscilloscope. I’m trying to check frequency response but the best I can do is spot frequency check. I’ve tried built in frequency response measurements using linear sine sweep of 300sec from external generator but results are way off my spot test , any way for a step by step instruction how to set it up , I’d like to run frequency response test in the typical 20-30kHz range using external generator .
Probably quite trivial but I got stuck on this

[VirtinsTech]

It looks like that you used the preconfigured panel setting "FRswph" to perform the frequency response test. In this method, the signal generator sweeps from 20 to 22050 Hz linearly over 300 seconds. The spectrum analyzer is set to peak hold mode with an FFT size of1024. The following screenshot below shows a loopback test of a sound card using this method.

To run the test, simply click "FRswph" in the second toolbar to load the preconfigured panel setting file, then start the oscilloscope and signal generator. The sweeping process can be observed in real time. After more than 300 seconds, the final frequency response curve will be displayed.

LinearFrequencySweep.png (89.05 KiB) Viewed 2504 times

Feel free to upload your test result here so we can help to diagnose the issue.

[Pete]

Thank you for the quick reply, does it apply if I use external generator to do the sweep?
I started using external one as USB card I use seems to have some 50Hz and harmonics and headphone out some 1kHz noise, anyway I need around 1V RMS signal and soundcard is not capable of outputting that much
Thank you again

[Pete]

I've tried again and it works , thank you.
Great software

[Pete]

Another question , if I were to take FR of the soundcard I use is there a way to use it as a calibration file when testing other devices?
One more, what is the most accurate way of taking FR ?
Thank you

[Pete]

It looks like that you used the preconfigured panel setting "FRswph" to perform the frequency response test. In this method, the signal generator sweeps from 20 to 22050 Hz linearly over 300 seconds. The spectrum analyzer is set to peak hold mode with an FFT size of1024. The following screenshot below shows a loopback test of a sound card using this method.

To run the test, simply click "FRswph" in the second toolbar to load the preconfigured panel setting file, then start the oscilloscope and signal generator. The sweeping process can be observed in real time. After more than 300 seconds, the final frequency response curve will be displayed.

The attachment LinearFrequencySweep.png is no longer available

Feel free to upload your test result here so we can help to diagnose the issue.

I've done same sweep using built in generator to simplify things :

Screenshot (465).png (88.54 KiB) Viewed 1786 times

question is how do I improve accuracy as zoomed in curve looks like below with a step every bin width:

Screenshot (467).png (61.65 KiB) Viewed 1786 times

Next question as before can I use this file as compensation for my future measurements ?
I know it's a basic stuff for others but I've got stuck , thank you for the help

[VirtinsTech]

1. Generally, with the Peak-Hold method, the slower the frequency sweep, the smoother the measured frequency response. You can also smooth the curve by right-clicking the Spectrum Analyzer window and selecting [Spectrum Analyzer Processing] > "Smoothing via Moving Average". Please refer to Section 3.3.2.8.1.4 of the software manual for details.

Alternatively, you can use the preconfigured panel setting "FRswlog" to perform the frequency response test. This method uses a logarithmic sweep combined with 1/96-octave analysis, resulting in a generally smoother frequency response. You may need to adjust the trigger level so that the Oscilloscope captures the entire sweep from start to end in one frame.

2. After the frequency response is obtained in the Spectrum Analyzer, right-click on it and select [Spectrum Analyzer Generate Frequency Compensation File (Flat)] to create a frequency compensation file. This file compensates for the sound card's unflatness, allowing it to be used for measuring the frequency response of other devices. To load the frequency compensation file, right click the Spectrum Analyzer and select [Spectrum Analyzer Processing]>"Compensation1" or "Compensation 2".

[Pete]

Thank you I’ll try this after my holiday,
I have watched a loop back video in educational section , very informative btw are there any more videos anywhere to be found the reason I ask forum is a bit glitchy and keep coming up with the error