Stereo Crosstalk Measurements with Signal Predator - Avatar and Elenos Indium Digital Series

I was playing with a 500W Elenos Indium Digital Series and a Signal Predator - Avatar BE Test Set , measuring the crosstalk .
With the Elenos Indium Digital Series Exciters it is possible to set the Pilot Tone Phase at 19 KHz  in steps of  0.01 ° , as in the second raw of the screen in the picture .

Slowly adjusting this Pilot Phase I was able to measure with the Elenos Signal Predator or Avatar BE Crosstalk in excess of 100 dB @ 400 Hz !

This allowed me to plot the table and graph of the sensitivity of the Crosstalk respect to the Phase of the  Pilot .

Pilot	Pilot	Crosstalk
Phase (°)	Delta Phase (°)	dB @ 400 Hz
0,00	0,00	110
0,01	0,01	100
0,05	0,04	90
0,16	0,11	80
0,44	0,28	70
1,16	0,72	60
2,45	1,29	50
4,90	2,45	40
9,23	4,33	30
17,25	8,02	20

Easy to see that from the table and graphs ,  for instance , when we are measuring 110dB of crosstalk , a shift of the phase of the Pilot of only 0.01°, get the crosstalk worse of 10 dB ! 

This accounts why FM Analog crosstalk is very difficult to be mantained high in the trasmission path.