Jump to content
Electronics-Lab.com Community

a problem


Recommended Posts

Can someone please give me the answer of following question.

the transmitter operates at a frequency of 1GHz, it is connected to an antenna of gain 10dB. the cable connecting the transmitter to the antenna has a loss of 3dB. the reciever has an antenna with a gain of 0dB and there is no other loss at the reciever. the distance between the transmitter and the reciever is 6km. the double sided noise power spectral density at the reciever, No/2 is 10e-16 W/Hz. assuming free space path lose between the transmitter and the reciever antennas. calculate the power needed at the transmitter to maintain a demodulater BER of less than 10e-3  ?

Link to comment
Share on other sites


10dB gain and a 3dB loss accounts for a net gain of 7dB for the receiver...
Free space has a trasfer function of 1.so the power spectral density at the receiver  is the same as that at the transmitter.
Assuming FSK transmission
Probability of error=1/2*erfc(0.6*Es/No)
if u are using ASK then 0.6 is replaced by 0.25
it is 1 for PSK.
For a giver BER i.e probability of error u can get signal energy....

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...