I trying to run a GMSK mod/demod test under GRC. My objective is to
create a single GSM-like burst and to store it in a file. The waveform
should have defined bits (by now I assume them to be random).
Thus I created a flowgraph that looks like this
Random Source (fixed # of samples, no repeat) -> Packet Encoder -> GMSK
Mod (->File Sink gmsk_tx) -> GMSK Demod -> Packet Decoder -> File Sink
(integer of bits_out)
If I keep increasing the number of bits in Random Source, I have
noticed that the number generated complex samples (I read them into
MATLAB using read_complex_binary) stays constant at 8496 complex samples
until 255 modulated bits. From 255 to 383 it is 28496, from 384 to …
it is 38496. Are these the bursts? Why are the bound to integers of
When forming a loopback, reading the modulated signal and
demodulating it, the bits_out are not demodulated when reading the file
bits_out via read_int_binary. Whats wrong with the flowgraph?
I attached the respective .grc file. I appreciate any help!