[time-nuts] TAPR TICC boxed
holrum at hotmail.com
Sun Apr 2 09:59:34 EDT 2017
The autotune cable delay nulling feature works by putting the TICC into debug mode which outputs time stamps (and other info) of both channels. Since each channel is being fed by the same signal, the stamps of each channel should be the same. Heather calculates the average chA-chB difference over a period of time and uses that difference to set the chA "fudge factor" which the TICC firmware subtracts from the chA readings. This nulls the relative offset between the two channels, but does not (and cannot) determine the absolute delay offset of each channel.
> Its usually not possible to uniquely assign individual channel delays in this way, however swapping cables allows the cable delay mismatch to be eliminated from the measurement of the differential delay between channels. Eliminating the effect of cable delay mismatch can be useful when adjusting narrowband quadrature splitters ect.
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