To convert this complex signal to a real, one has to do
this according to the following formula, isn't it?
x(t) = Yc(t)Cos(2*pi*fc*t) - Yi(t)Sin(2*pi*fc*t) where
Yc(t) -> Inphase component,Yi(t)-> Quadrature component, fc -> Carrier frequency, x(t) -> real signal.
I looked at the block "complex_to_real" and it outputs the Inphase component
as the real signal. Is it because, "fc" is 0Hz as the signal being at
baseband? I think this sounds right.
I want to mulitply this real signal with a PN sequence and then pass the result
on to a costas loop which takes a complex input. I want to know how can we
get a complex signal from a real one. Is there a block that does that?
The book "Communication Systems" by Simon Haykin 2nd edition says,
- The complex envelope g_complex(t) equals a frequency shifted version of the pre-envelope g+(t) as shown
g_complex(t) = g+(t)*exp(-j2*pi*fc*t), where fc-> carrier frequency.
and the pre-envelop is defined as, g+(t) = g_real(t) + j*g_hilbert(t).
I suppose this is what I need to do to get what I want. Is there a block that does it all?
Thanks,
Peng.
P.S. - I am sorry but I thought to make sure before I go ahead so that I don't spend time doing things that may be unnecessary.