The measuring equipment used on this website?

[Hayk]

Thank you for the filter advice.
I added 11th eliptic -60db 15khz filter and adjusted the pulse to be 10us on every 0 crossing once high passed it forms positive and negative impulse that generates only pair harmonics. I adjusted the level to 0.005% distortion measured at the sampler input.

The FFT of the input of the sampler and the output are shown for 50 cycles, the output sampler has slight attenuation.

 

[Hayk]

I found the same amplifier Fosi v3 mono, measured with audio band sample rate and 1Mhz bandwidth. See how the distortion in the audio band is measured much higher with high frequency sampling.

 

[staticV3]

See how the distortion in the audio band is measured much higher with high frequency sampling.

Much higher is a bit exaggerated.

Eyeballing the two graphs, H2 is increased by 10dB with higher BW, and the rest appears to be within margin of error.

 

[voodooless]

Asked and answered already:

The measuring equipment used on this website?

At what sample rate are measured the tested devices?

www.audiosciencereview.com

 

[Hayk]

The 4th harmonic shows the AD modulation defect. Compare the results.
13db is 4.5x higher.
If you adjust your eyeball, the second harmonic passes from. -113db to -93db.

 

[staticV3]

The 4th harmonic shows the AD modulation defect. Compare the results.
13db is 4.5x higher.
If you adjust your eyeball, the second harmonic passes from. -113db to -93db.

 

[Hayk]

Nice animation.
You can convince a noob that there is not much visible difference, but by numbers, the difference of the second harmonic is 10 times higher.
In other words, by changing the sampling rate, the THD loses a zero in its number.

 

[oratory1990]

Nice animation.
You can convince a noob that there is not much visible difference, but by numbers, the difference of the second harmonic is 10 times higher.
In other words, by changing the sampling rate, the THD loses a zero in its number.

Due to a lower performance analog-to-digital converter being used for high bandwidth signals in the signal analyzer: https://www.audiosciencereview.com/...ment-used-on-this-website.62520/#post-2293522
Meaning you get a *less* accurate result when using the higher sample rate on this signal analyzer.

 

[Hayk]

THD of AD7760 is -103db which is much lower what it measures here.

 

[voodooless]

THD of AD7760 is -103db which is much lower what it measures here.

You don't know the input voltage.

 

[Hayk]

-0.5dbfs but for 100khz input probably 1.2Mhz bandwidth (not specified)
Another number with 0.5dbfs ?khz says -105db.

 

[voodooless]

-0.5dbfs but for 100khz input probably 1.2Mhz bandwidth (not specified)
Another number with 0.5dbfs 100khz says -105db.

But you don't know if the signal was at -0.5 dBfs... The plot is just normalized to 0 dB.

 

[staticV3]

input voltage into the APx was sqrt(5*4)=4.5Vrms

Though we still don't know the input voltage into the ADC.