On 03.06.2015 17:29, [email protected] wrote:
hello felix,
>>please remember to always reply to the list.
i'm sorry, i'm new at this. i have checked my configuration and i hope
it works the next time.
to mix up the baseband signal to 12khz or higher to short wave
(3-30mhz) should be the same procedure. i have tested it by using a
multiply block and a signal source block as the carrier frequency.
but there is an other question: if i configured my system as
described, can i be sure that the bandwidth of each sub carrier has
the bandwidth and symbol duration as shown by the equations?
used_bw = occupied_carriers * df
df = used_bw / occupied_carriers = 10khz / 228
df = 43.86hz --> tsym = 22.8ms
it's very confusing why i have to adjust my used bw by changing the
sampling rate. when i follow the equations and the standard i choose
one mode (RM A, SO 3). that means i have to use 228 carriers
and have a symbol duration with 24ms which leads to 41.66hz carrier
spacing. so the used bw is 228 * 41.66hz = 9.5khz (approx. 10khz).
this bw should be fix and should not change by the sampling rate.
sorry for the maybe silly questions but i want to keep on that stuff.
Well, the measurable on-air bandwidth is always defined by the
speed/rate at which your soundcard processes your digital samples. If
you remember that B ~ 1/T and that the rate of your soundcard controls T
it becomes obvious that changing the sample rate changes the bandwidth.
If you don't want that, you could use a resampler that adapts its
resampling ratio to the sampling rate of the soundcard.
Felix
@Marcus
you mean if there were pilots for a channel estimation in the
transmitted signal?
alphonso
--
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)
Felix Wunsch, M. Sc.
Research Associate
Kaiserstraße 12
Building 05.01
76131 Karlsruhe
Phone: +49 721 608-46276
Fax: +49 721 608-46071
E-Mail: [email protected]
www.cel.kit.edu
KIT -- University of the State of Baden-Württemberg and
National Laboratory of the Helmholtz Association
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