Hi Nick,
Thanks for your quick reply!
I have to use a 10M sampling rate in my case, but due to computer constrain, modes_rx will cause overflow when used directly with -r 10000000. I gauss it's because it's sampling data in float? I am using a GPSDO with USRP.
So I record data in short at 10M sampling rate, convert from short to float and then input to modes_rx. The output looks like this:
{{{
(27 0.00000000) Type 0 (short A-A surveillance) from dc2ed9 at 45900ft (speed 600-1200kt)
(23 0.00000000) Type 4 (short surveillance altitude reply) from 2443b0 at 59800ft (GROUND ALERT)
(24 0.00000000) Type 4 (short surveillance altitude reply) from 3b1fc3 at 3200ft (SPI)
(21 0.00000000) Type 21 link capability report from d5ca0e: ACS: 0xda21, BCS: 0xc923, ECS: 0xee, continues 8 ident 123e
(22 0.00000000) Type 5 (short surveillance ident reply) from 5ad8b4 with ident 728 (GROUND ALERT)
(37 0.00000000) Type 17 BDS0,9-1 (track report) from 7805dd with velocity 218kt heading 238 VS -1664
}}}
The timestamp are all zeros.
Another question is that if I use modes_rx, how to save the sampled complex baseband signal? Is the data saved somewhere that I've missed?
Best regards,
Cheng Chi