[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[linrad] Question about time delay compensation

I have a question for Leif.
In another forum we were discussing about phase and time compensation,
and someone came up saying that Linrad is capable of compensating a time
delay that may exist in e.g. the left channel of a sound card, but not 
in the
other one, or viceversa.  This because some testings have measured that
cheap sound cards exhibit about 14 microseconds of delay on one channel
with respect to the other, probably due to the fact that there is just a 
ADC, time-multiplexed between the left and right channels. This time delay
plays havoc with the ortogonality of the I and Q signals.

A fixed time delay means a phase difference varying with the frequency, so
the normal methods of phase compensation do not work in this circumstance.
What is needed is an adjustable fractional time delay filter.

Does Linrad have such a feature ? If yes, could you Leif please tell me the
routine where it is implemented ? I am more than willing to copy it  :-)

Thanks for any answers

73  Alberto  I2PHD