Re: [Discuss-gnuradio] CPFSK mod/demod + strange behavior

[Olivier Goyette]

As promised, I'm giving the documentation I talked about yesterday and hop it will clarify some of the things we discussed earlier.
https://www.dropbox.com/s/1blrausidm66tg4/DO-282B%20with%20Corrigendum%201_bx87er.pdf?dl=0

the password is bx87er

on page 23, you will find what the transmission spectrum should look like

on page 91, what the receiver should be made of

on page 95, what is the decoding process

on page 256, what the spectrum should look like

and on appendix H3, the section talking about RRC

hope it will help you understand

thank you

Olivier

2016-06-10 9:02 GMT-04:00 Achilleas Anastasopoulos <address@hidden>:

Marcus,

any PAM signal with symbol rate R can be transmitted using bandwidth R/2

(essentially a sinc pulse; this is the case when you put 0 as the roll-off factor of an RRC).

I thought your comment was not specifically for CPFSK, 

but general transmission schemes thus my clarification. 

If it is specific for CPFSK then kindly disregard the above.

Achilleas

> So, I will need you to *explain* how you can transport 1.somethingMb/s
> through a 625kHz wide channel if every time you use that channel to
> transmit a symbol, only one bit can get sent. How do these numbers add
> up for you? You've got a serious problem with your pulse shaping, there.

On Thu, Jun 9, 2016 at 3:04 PM, Achilleas Anastasopoulos <address@hidden> wrote:

Why are you using the RRC filters?

I hope you are realizing that filtering a CPFSK signal is not the same as filtering its instantaneous frequency (which is a PAM signal with rectangular pulses).

As a result, the next question is why in your poly-phase filter you are using RRC filter taps?

Achilleas

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