I am not familiar with the DATA/MEM function but I would expect that it is intended to give the ratio of two measured gains. Do you know what the actual reported gains were for the two attenuators? I would expect 6dB/3dB to yield 3dB (or 2 if you make it report in linear units). However, could it be that measurement error and error in the exact attenuation in the devices means that the ratio of their two gains is actually closer to 2dB and the device is rounding off? A better way to determine what is going on would be to use two devices with a greater difference in the gain (like a 10dB atten and a 3dB atten, or if you only have a 3dB and a 6dB, test just the 3dB and then test both in series -i.e. 9dB, the difference should then be 6dB). Sean On Sat, Nov 13, 2010 at 2:06 AM, Justin Richards wrote: > Understanding a Network Analyser when using to compare a "known good" > device 2 port network against an unknown. =A0Experimented with > attenuators first as follows:- > > Intial Device under test 3dB attenuator this is saved to memory. > > Second decice under test 6dB attenuator. > > The math function DATA/MEM is then selected and we get 2dB. > > I thought it would have been 2 units not 2dB. > > So is 6dB/3dB =3D 2dB or 2 Units. > > This is across a range of about 50MHz starting at about 5MHz, not that > this matters but is added for completeness. > > Justin > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .