New REW update

[rfort]

Just updated REW, had to recalibrate, a 1Vrms input signal was -20dBV down instead of 0dBV. After recalibrating, REW displays 34.52V as the "FS Sine Vrms" value. Correct value would be 3.452Vrms. Might need another update, decimal off one place to the right in some software line. Also explains why after updating it was -20dBV down.

 

[John Mulcahy]

I can't reproduce this, can you provide some more info? What input rms voltage are you applying for calibration and what dBFS level does it produce on the input level meter? Any attenuation or level controls along the input path?

 

[rfort]

I am using REW to measure noise levels and PSRR on power supplies and am very happy with the changes to allow mV uV inputs. I regularly use a +60dB LNA and that allows me to directly read the measurments.

I used a Rigol signal generator to input 1Vrms at 1kHz into my USB soundcard, a Focusrite Solo 3rd gen, no attenuation in the path. I do use BNC connectors and attached a Rigol bench multimeter to the output of the signal generator with a "T" BNC connector to ensure the voltage I input is correct.
With 1Vrms at 1kHz going into the soundcard, I hit he calibrate button and enter the reading on my multimeter, 997.7mV. You know have me wondering if I put the mV behind the entry..

Let me check that I entered it correctly and get back to you, it may be on my end.

 

[rfort]

The issue was on my end. I entered mV after my reading when it was in Volts. I performed the calibration and it is correct now. Sorry to put you through checking an issue that don't exist.

 

[John Mulcahy]

No problem, issues that go away by themselves are my favourite kind