FSK using VCO

GNU Radio
1

HI all,

      I'm developing an underwater modem which uses acoustic signal

for
transmission and reception .for that i need to have a FSK
modulator.since
CPFSk is not practically possible in underwater ,i decided to use VCO.I
have to modulate data from a file sourc(output type byte) using 10khz
carrier.i don’t know how to do this.when i connected a file source
-uchar
to float- vco -scopesink and observed output i couldn’t see what i was
expecting.can’t i input the vco with a file source?please help me.

thanks in advance
ANJU

2

Anju,

Try connecting these

data_src(0,1)==>chunk to symbol(-1,1)==>fm
modulator(sensitivity=(2pi(freq_sep/2.0))/samp_rate))

where freq_sep = symb_rate (for non-coherent detection)

On receiver side u can use quadrature demoulator

-Adeel

3

One thing i forgot , there should be upsample(pulse shaping ) OR repeat
by
N block between “chunk2symbol” and “fm modulator”