mayur_CEN wrote:
I am sorry for being so impatient.Actually I have been experimenting with
this problem for a long time,so i am a bit eager to find the solution.You
guys are doing a great job helping out people with their problems.I did not
mean to offend anyone.
I have uploaded the code.I will explain to you in detail how i am conducting
the experiment.
I am using 2 daughter boards for sending and receiving simultaneously.
I am checking the output of the fm transmission by running a nbfm_tx
receiver program simulated in grc
When I send 1 channel ,the audio can be heard clearly
As I increase the number of channels,the audio strength decreases which I
think is due to interference.
What I want to know is how do I increase the signal strength and reduce
noise as I increase the number of channels.
What you are seeing as noise is most likely clipping.
As you increase the number of transmitted signals, you need to decrease
the power per signal since you need to stay maintain linearity.
For example, say you are transmitting 1 signal at max amplitude and
power. When you move to 2 signals, you need to use 1/2 the max
amplitude for each signal, which will give you 1/4 the max power in each
signal. If you have X signals, you need to give each one 1/X the max
amplitude, which will give each signal 1/X^2 of the max power.
If X is very big (more than 20 or so), you don't necessarily have to
reduce the amplitude quite as much as 1/X, but for small X you do.
Matt
_______________________________________________
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org
http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
