Re: AWGN parameters

But how come the sine wave doesnt come into picture : as i increase
the amplitude of the sine , the BER decreases , so r u sure that the
input power to the channel has nothing to do with the sine amplitude
?

Chandresh Vora wrote:


If you are feeding the output of QPSK modulator directly to AWGN
Channel
block, input power should be 1. QPSK modulator maps binary/symbol
inputs to
QPSK constellation points which lie on unit circle. So the average
signal
power is 1.

Note that these blocks (infact, both the products - Communications
Toolbox
and Communications Blockset) perform baseband processing. So the
carrier
sine wave does not come into picture. Baseband processing is
defined here:

<http://www.mathworks.com/access/helpdesk/help/toolbox/comm/ug/a1041263435.html#a1042556438b1>

Or see this section of Communications Toolbox documentation:

Modulation->Digital Modulation

HTH,
Chandresh


"makanaky" <midooo_85@xxxxxxxxxxx> wrote in message
news:ef5bd9c.-1@xxxxxxxxxxxxxxxxxxxxxxxxxx
hi ,

i am simulating QPSK modulator /demodulator with AWGN channel
in
between .... but i am confused on the parameters i must place
in
the
AWGN channel block .... i placed these parameters but i dont
know
if
it's right or not so plz correct me if i am wrong ok :

mode : signal to noise ratio (Eb/No)
number of bits per symbol : 2
symbol period : 2*bit duration (before multiplying by sine )

input power : should i put it =(1/2*Ac*Ac ) where Ac is the
amplitude
of the sine wave ?

plz reply me ASAP .... if u need more info tell me to send u my
model


thanks



.

Relevant Pages