How do I set up my tone generator in REW to take measurements please?

[Nkam]

Fellas

how do I set up my tone generator in REW to run a 1khz sine wave to measure a DAC with my RME PRO?

i can’t get it down to 0dbfs.

the attachment isnt how I set it up finally but that’s the screen which I’m not sure how to set up properly.

any help would be much appreciated !

and also for the jitter test please!

 

[charleski]

This needs to be set to dBFS.
The dBV and Volts settings are only valid once it's been calibrated with an external multimeter.

 

[Nkam]

View attachment 274979
This needs to be set to dBFS.
The dBV and Volts settings are only valid once it's been calibrated with an external multimeter.

and do I set DBFS to 0?
thanks so much!

same settings for jitter?

 

[charleski]

Yes, if you set it to 0dBFS then REW will generate a full-scale waveform and feed it to your DAC.

The J-test signal generated by REW is fixed at -3.01dBFS.

 

[Nkam]

How about the sensitivity settings on my RME Pro

I have them at around +13dbu

 

[Nkam]

If I go higher than +13 dbu the DBFS in REW increases.

when it’s at +13dbu I get -3.84dbfs in REW

 

[LTig]

How about the sensitivity settings on my RME Pro

I have them at around +13dbu

Input or output, or both?

 

[LTig]

If I go higher than +13 dbu the DBFS in REW increases.

when it’s at +13dbu I get -3.84dbfs in REW

If you do a loop back measurement of the RME you have to set both input and output to the same dBu reference level. Then the real time display should show the peak level of the test signal with about the same value as set in the generator panel (as far as I remember).

 

[Nkam]

How’s this?

do these look right ?

far left is with the Intona , middle is the Jitter with Intona and far right attachment is with no galvanic isolation.

 

[Nkam]

And these are the right settings when measuring at 48k?

 

[Nkam]

@VintageFlanker
can you help me out please with doing some more measurements with REW and my RME ADI PRO to my other DAC?

can I do measurements using REW to see how the DACs internal filter works ?

 

[charleski]

How’s this?

do these look right ?

far left is with the Intona , middle is the Jitter with Intona and far right attachment is with no galvanic isolation.

Set the measurement scale in REW to dBFS.

can I do measurements using REW to see how the DACs internal filter works ?

There are two tests that are typically done, in both the ADC for the measurement is sampling at 96 or 192kHz:
Feed the DAC a white noise signal at 44100Hz. Set the level so the noise peaks at 0dBFS, measure, and then set it at -3dBFS and measure again.
Generate a 0dBFS mixture of 19 and 20kHz tones at 44100Hz.

The easiest way to check the phase of the filter is to generate a 100Hz square wave at 44100Hz and take a snapshot in the oscilloscope screen.

 

[Nkam]

Set the measurement scale in REW to dBFS.


There are two tests that are typically done, in both the ADC for the measurement is sampling at 96 or 192kHz:
Feed the DAC a white noise signal at 44100Hz. Set the level so the noise peaks at 0dBFS, measure, and then set it at -3dBFS and measure again.
Generate a 0dBFS mixture of 19 and 20kHz tones at 44100Hz.

The easiest way to check the phase of the filter is to generate a 100Hz square wave at 44100Hz and take a snapshot in the oscilloscope screen.

pardon I didn’t understand. I set in the parameters 44.1k.

now how do I set the below noise generator please?

super appreciate it !

 

[charleski]

This is the peak level of the noise. Adjust the generator level until this reads 0dBFS. Then measure again with the peak set to -3 or -4dBFS.

 

[LTig]

@VintageFlanker
can you help me out please with doing some more measurements with REW and my RME ADI PRO to my other DAC?

can I do measurements using REW to see how the DACs internal filter works ?

Yes but you must use another ADC to measure signals, and the DAC must be fed by another player. E.g. you use foobar 2000to play white noise into the RME at 44.1 kHz and use the separate ADC at 96 kHz sending data to REW. This is because you cannot set different sample rates for ADC and DAC.

 

[VintageFlanker]

@VintageFlanker
can you help me out please with doing some more measurements with REW and my RME ADI PRO to my other DAC?

Later, once I'm at home, I could have a look.

 

[Nkam]

View attachment 275104

This is the peak level of the noise. Adjust the generator level until this reads 0dBFS. Then measure again with the peak set to -3 or -4dBFS.

This is what I’m getting.
what am I doing wrong?

pardon

 

[LTig]

And these are the right settings when measuring at 48k?

Yes, but you should also click the upper (lock frequency) and lower (add dither) selections.

 

[Nkam]

Later, once I'm at home, I could have a look.

Do I have these settings wrong?

 

[Nkam]

Yes, but you should also click the upper (lock frequency) and lower (add dither) selections.

got it. Thanks !