Modelling error in Multisim's Tektronix TDS2024 FFT option

[adnnzi]

The user's manual for Tektronix TDS2024 mentions that a 1 Vrms signal will be displayed as 0 dB peak in the FFT view. However, when I connect a 1 Vrms source to Tektronix TDS2024 scope in Multisim, I get a peak at 3 dB. This is only possible if National Instruments is using peak value in 20 log(V1/Vref) forumla instead of the RMS value which an actual (i.e., physical) TDS2024 oscilloscope uses.

Could someone confirm if its really a mistake or is it supposed to be like that?

Thanks in advance.

(P.S. Attached is the Multisim file)

[gmack]

You nailed it!  In the (old SPICE) analyses everything is peak amplitude (as it is in MULTISIM's "signal" sources).  NI's additon of RMS options to "power" sources and not changing the corresponding "AC Analysis" from peak to RMS kinda added to the confusion!  It seems to me that MULTISIM should stick to one or the other for consistency and make it clear what it is!  Most EEs likely think that RMS is the "default" whereas most CSs (like the origimal Berkeley SPICE developers) likely thought peak was (as in Asin(omega)).

[adnnzi]

Thanks gmack!