Re: [Discuss-gnuradio] Multiplexing modulators

[Marcus D. Leech]

On 21/06/2011 9:28 AM, John Ackermann N8UR wrote:
> In GRC I would like to combine the outputs of several NBFM modulator blocks to 
> drive a USRP sink.  The idea is to output several discrete channels within the 
> USRP transmit bandwidth, e.g., three signal channels at -30 kHz, 0 kHz, and +30 
> kHz offset from the USRP tune frequency.
>
> I'd appreciate suggestions on how best to accomplish this.
>
> Thanks,
>
> John
Use a frequency translating FIR filter on all the modulator outputs, and 
then just additively combine them prior to presentation
  to the USRP.