Itsu,
Yes please re-check the results in and around 1-2MHz using R2 only as I really don't think you will see any gain at 190kHz. Plus the deskew differential becomes more effective in producing errors as the frequency increases.
Pm
Spot on PM, back in business.....? COP=1.2 @ 1MHz
Paralleling the both used 51 Ohm metal film and metal oxyde resistors with a 1nF silver mica cap shows resonances at 18MHz, see SA screenshot.
This equates to 0.078uH inductance for both 51 Ohm resistors used.
When omitting the current probe, and more important.... to ignore the -80° phase shift..... i redid my measurements using the blue R2 (1 Ohm) csr trace as current value.
I started at 1MHz and this caused the phase shift to lower to -64.5°, and calculating the input (both by the scope math function as by hand) shows a 143mW input.
Using the CH3 purple probe value in the output calculation i now get 3.005² / 52 = 173.6mW so a COP of 1.2
EDIT i calculated the output power via the math trace CH2 (Blue) x CH3 (purple) and it confirmed a COP 1.2 with respect to the input power
See scope screenshot which shows:
yellow; voltage across the FG
blue; voltage (= current) across the 1 Ohm csr
purple; voltage across the 51 plus 1 Ohm resistors
red; math of yellow x blue is averaged power input
At 500KHz i see a COP = 1.18 phase shift yellow/blue -75°
At 1MHz i see a COP = 1.2 phase shift yellow/blue -64°
At 1.5MHz i see a COP = 1.125 phase shift yellow/blue -51°
At 2MHz i see a COP = 1.04 phase shift yellow/blue -45°
The current probe deskew function (thanks PM) is to limited (±10ns) to correct the skew, so cannot be used to double check.
I know these COP values are only marginal, but its a start.
Are we sure that what we are using is the correct way to calculate the output thus the COP?
Regards Itsu