[time-nuts] Testing frequency pulling on a DYI counter

[Erik Kaashoek]

A well know technique for measuring phase pulling is measuring the phase 
of two signals 0.01 Hz or less apart.
To test if this pulling has a relevant impact on frequency measurement 
the ratio between two 10 MHz output signals from a signal generator was 
measured. One output signal was changed in frequency in steps of 0.01 Hz 
between 9999999 Hz and 10000001 Hz [1]
The plot shows the error at all measured frequencies differences (+/- 
1Hz in steps of 0.01 Hz) is below the accuracy target of +/- 1e-9
Is this a relevant measurement for detecting possible interaction 
between the two inputs of a frequency counter?
Any suggestions for how to do a performance evaluation of a frequency 
counter?
[1] http://athome.kaashoek.com/time-nuts/Freq_error.PNG