At 07:24 AM 12/3/2005, Edson Pereira wrote:
Hello:
I will ask this here before diving deep into the DSP books. :-)
Given the SDR-1000 impulse response using the internal pulse generator,
how could one use the results (a complex FFT) for correcting the IQ
phase and magnitude errors in the frequency domain?
At a simplistic level, it's just taking the FFT of the input signal, and
dividing by the FFT of the impulse response.
One can also do it in the time domain. Use the impulse response to build a
FIR filter that turns the impulse response into an impulse.
There's some trickier aspects:
you want to avoid dividing by zero, for instance..
and,
the measurement of the impulse response is "noisy", so you might actually
do better by using the measured response to build an idealized model of the
distortions, and then use that to build the equalizer. (For instance,
maybe you'd smooth the measured response or fit it with a 10-20 term spline)
73,
-- Edson
_______________________________________________
FlexRadio mailing list
[email protected]
http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz
James Lux, P.E.
Spacecraft Radio Frequency Subsystems Group
Flight Communications Systems Section
Jet Propulsion Laboratory, Mail Stop 161-213
4800 Oak Grove Drive
Pasadena CA 91109
tel: (818)354-2075
fax: (818)393-6875
