Is this the same baseband signals copied at several place ?
It is yes.
What you can do is :
* First modulate the signal to a narrow sample-rate (just enough for
the modulation)
* Upsample that signal to 1 Msps.
- Depending on the ration between the narrow rate and wide rate, it might be
beneficial to do that in several steps.
- So for instance you would go from 10 kHz to 100 kHz first with a
filter that's relatively sharp
- Then you would go from 100 kHz to 1 MHz with a second filter than
can be much more relaxed (i.e. larger transition bandwidth and so much
less CPU usage)
* Then use several rotators to position it at the various places you
need it in the 1MHz bandwidth
* And finally add the output of all the rotators.
Thanks for the suggestion. I'll give that a go.
There is also the so called Polyphase Filter Banks, but that only
works if you need carriers that are all equally spaced. And is also
only a benefic if you really fill a significant number of them.
In my case the output channels are arbitrary, so your first suggestion sounds like the one I need to implement.
Thanks for taking the time to respond.