Re: [Discuss-gnuradio] Decoding CPFSK

[Ed Criscuolo]

Andrew Rose wrote:

> 2. 1200Hz/1800Hz continuous-phase FSK encoding 1200 bits per second.
> i.e. each output bit is either 1 cycle of a 1200Hz wave (1-bit) or 1.5
> cycles of an 1800Hz wave (0-bit).  The start of each bit is at a
> zero-crossing (although there are obviously zero-crossings which aren't
> the start of a bit).

What you are describing is called Mean Shift Keying.  It is a 
specialized form of FSK that is designed to have more efficient
bandwidth utilization.  I would guess that you could use the
Gaussian Mean Shift Keying (GMSK) demodulator, or construct
your own using a quadrature demodulator  and a root-rased-cosine
filter.

@(^.^)@  Ed