2 Jan
2014
2 Jan
'14
1:09 p.m.
Good to know that. Actually I also notice that radio astronomy is
attracting more and more signla processing researchers to work on it. Some
conference, such as ICASSP, envn setup a dedicate session on radio
astronomy. There is a radio astronomy called "DOME" are carrying on, which
involves computation on massive data and signal processing algorithm.
You have notice the problem that re-tuning will casue lossing
synchronization. That's also the problem I considered.
Because we always want the rtl-sdr work in the band we are interested, but
unfortunatelly in that band there maybe no any pre-known reference signal
for us to do synchronization. So a possible solution maybe make a beacon,
which can generate ultra-narrow-band or ultra-low-power signal in the
target band to help us do the on-line calibration. Any better ideas to
avoid this dedicate beacon?
On Mon, Dec 30, 2013 at 11:09 PM, Leif Asbrink <leif(a)sm5bsz.com> wrote:
Hello Jiao,
My thought is doing the compensation by software
according
to a common source over the air instead of over the hardware.
Do you think it is doable?
Yes. This is most certainly possible. The same thing was done long
ago in radio astronomy. Two big telescopes on different continents
made recordings aiming at a coomon direction in the sky. By
evaluating the recordings they could make interferometry.
http://en.wikipedia.org/wiki/Very-long-baseline_interferometry
This is a very interesting approach for the future.
With several dongles that have some signals in common it
will be possible to synchronize in software.
One of the common signals could be a GPS diciplined frequency
standard that the software could use to provide extreme
frequency stability on the processed signals from all the dongles.
Once syncronization is arranged one could use the multi-channel
antenna for interference suppression and to improve S/N of any
desired signal.
And what would be the bottleneck according to
your experience?
There is a lot of code that has to be written, but
I do not think there is any bottleneck to worry about
in hardware
Any possibility to tune the hardware by software
after we
estimate the synchronization error in frequency and timing?
The entire passband of
the dongles will be coherent.
You can tune to any frequency within the passband and also
evaluate several frequencies at the same time.
In case one wants to change the center frequency one would
loose synchronization and one would have to restart the
synchronization procedure.
SDR has just begun. Most of the interesting things have
not yet been done:-)
Regards
Leif / SM5BSZ