Hi,
I am transmitting using the flowgraph: vector src-> FIR interpolator (with RRC filter as below) -> MultiplyConst -> USRP Block
FIR filter - firdes.root_raised_cosine(32, samp_rate, sps, 0.55, int(11*sps*32)), with
center freq= 400kHz
samp_rate= 1k
I am listening using other USRP with
center freq= 400kHz
You can see the spectrogram at the receiver. I want to do narrowband(1 kHz) transmission hence I am keeping the sampling freq at transmitter at 1k.
While I increase the signal amplitude(using MultiplyConst block with slider), I see there is more and more spillage of energy in the neighboring frequencies!
Is there a way to remove that spillage from the transmitter and have a cleaner transmitter ?
If not, how can I atleast mitigate it to the minimum ? is there something I can do with RRC filter parameter or any other way ?
In the figure: 1 - when amplitude is large; 2 - when amplitude is turned down
Thanks,
Abhinav