PPM Signal Generation

GNU Radio
#1

Hi,
is it possible to generate a PPM signal with GNU Radio + USRP2 with a
bit rate of 1MBit/s?

In particular, I want to transmit Mode-S replies which are modulated
using PPM on 1090Mhz. In order to do so, I have to send 0.5s wide
pulses with time-shifts of 0 s or 0.5 s.

The generation of samples on the host is of course no problem, and also
the 1Gbit link to the SDR should suffice to transfer e.g. 4
samples/pulse. The question now is, whether the hardware (USRP2 + WBX
Rev 2) is fast and accurate enough to produce the correct RF-signal.

I played a bit with 2 USRPs, the XCVR2400 (one as sender, one as
receiver) and GRC but I wasn’t able to generate a nice square-signal
with a frequency of 1Ghz which would be very similar to the one I need.

So I would appreciate any thoughts, ideas and suggestions.

Matthias

#2

yes it’s possible and I already built a full mode-s transmitter using
gnuradio and it’s work very nice.

#3

yazeed mkr wrote in post #1036173:

yes it’s possible and I already built a full mode-s transmitter using
gnuradio and it’s work very nice.

Dear Yazzed,

Currently, I also face the same problem that wish can generate a PPM
signal with GNU Radio + USRP2 with a bit rate under 1MBit/s. Could it be
possible that you can provide me some reference how to do it?

Millions Thanks,

Henry