On 6/7/07, Achilleas Anastasopoulos <[EMAIL PROTECTED]> wrote:
David,
as I explained in my earlier email,
the power you have to raise your signal is not always 2.
If h = 1/4 you need to raise your signal to the power 4.
In general ig h=N/D, you raise it to D.
dang it...
good call...thanks
David,
as I explained in my earlier email,
the power you have to raise your signal is not always 2.
If h = 1/4 you need to raise your signal to the power 4.
In general ig h=N/D, you raise it to D.
Achilleas
David Scaperoth wrote:
BTW, are you using the cpm.py hierarchical block that is
BTW, are you using the cpm.py hierarchical block that is
on the trunk? If yes, I attach a simple python code that
demonstrates the spectral line generation for a 4-CPFSK
with h=1/2.
I definitely see the spectral lines for your case, which I believe is
considered an MSK modulation. Unfortunat
The point where theory meets practice is what makes engineering fun.
If when you say "Nothing that modulates data has constant envelope"
you mean it in the same sense that passbands are never truly flat and bit
error rates are never 0, then I agree with you. But I claim that a
received CPM sig
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Nothing that modulates data has constant envelope. Plot the amplitude of
a BPSK or GMSK signal (after transmission, not simulation) sometime.
- -Dan
Achilleas Anastasopoulos wrote:
> Bob,
>
> this is not correct.
>
> The CPM signal is by definition
Bob,
this is not correct.
The CPM signal is by definition constant envelope.
It is defined as
s(t)=exp(j phi(t))
where
phi(t)= 2 pi int_0^t f(t') dt'
where
f(t)= h sum_k a_k p(t-kT).
Selecting the approprate pulse shape p(t) shapes the spectrum of CPM,
but regardless of the selection it has cont
Since the signal will not really have infinite bandwidth (instantaneous
transitions from one state to the next), the envelope will not be of
constant modulus. The signal will be amplitude modulated with a
component due to the data transitions. Looking at the modulus or
modulus squared will r
David,
one way to estimate the rate is to raise the CPM signal to an
appropriate power in order to generate spectral lines that can be easily
tracked.
The precise power is a function of the modulation index of your CPM
modulation. Eg, if you are using full-response CPFSK with h=N/D
(where N,D
hey all,
I am trying to demodulate a CPM (for now I'm doing it with 4-CPFSK signal
with Raised Cosine pusle shaping) signal without knowing the symbol rate (
i.e. the samples per symbol). does anyone know if this is possible? Papers
that I have read on timing recovery for CPM assume that the sy
