sniggerImp
Newbie level 3
I have 5 bursty bit streams which are to be modulated by MSK at different carrier frequencies.
The bit stream is zero ( if no signal is there) , or 1 or -1 ( 1-> logic 1 and -1 ->logic 0). each symbol ( 0 , -1 or 1 ) is sampled 8 times with the sampling interval = 4e-7 seconds.
How can I modulate these streams in MATLAB ?
After modulating them at different carrier frequencies (890,895,900,905,910,915 MHz) I have to sum them up ... or multiplex them .. to simulate the combined air channel traffic to be filtered into different bands later on using bandpass filters.
I have tried Simulink - but the MSK or the GMSK blocks do not ask for a carrier frequency specification.
The modem.mskmod function just converts my bit stream (consisting of only 1 and 0 ) into complex values ( which form the new signal constellation) which i don't know how to use to modulate using a carrier wave of the specified frequencies.
Please help !!
PS : And one more doubt ==> to simulate GMSK .. do i need to first filter the NRZ bit sequence using gaussian filter and then MSK modulate it ... OR .. vice-versa ?
The bit stream is zero ( if no signal is there) , or 1 or -1 ( 1-> logic 1 and -1 ->logic 0). each symbol ( 0 , -1 or 1 ) is sampled 8 times with the sampling interval = 4e-7 seconds.
How can I modulate these streams in MATLAB ?
After modulating them at different carrier frequencies (890,895,900,905,910,915 MHz) I have to sum them up ... or multiplex them .. to simulate the combined air channel traffic to be filtered into different bands later on using bandpass filters.
I have tried Simulink - but the MSK or the GMSK blocks do not ask for a carrier frequency specification.
The modem.mskmod function just converts my bit stream (consisting of only 1 and 0 ) into complex values ( which form the new signal constellation) which i don't know how to use to modulate using a carrier wave of the specified frequencies.
Please help !!
PS : And one more doubt ==> to simulate GMSK .. do i need to first filter the NRZ bit sequence using gaussian filter and then MSK modulate it ... OR .. vice-versa ?