Sirs, I have read in some of the wireless literatures that certain data are deliberately transmitted with higher power. However, I dont understand what increasing the signal power means and where exactly happens. Does increasing power means simoly increasing the amplitude and in case of wireless applications, does this happen in RF section of the transmission Thanks, manish
controlling signal power
Started by ●June 9, 2013
Reply by ●June 9, 20132013-06-09
On Sun, 09 Jun 2013 07:09:53 -0500, "manishp" <58525@dsprelated> wrote:>Sirs, >I have read in some of the wireless literatures that certain data are >deliberately transmitted with higher power. However, I dont understand what >increasing the signal power means and where exactly happens. > >Does increasing power means simoly increasing the amplitude and in case of >wireless applications, does this happen in RF section of the transmission > >Thanks, manishIt depends on what you're talking about. Are you talking about something like a pilot tone that has more power than the rest of the signal or something like that? Automatic power control for reliability? Changes in power can be made by adjusting the signal amplitude. This can be done anywhere in the transmit chain, either digital or analog. Where it is actually done depends on what you're talking about. Large changes in power are almost always done in the RF section with a variable gain amplifier. Small changes can be, but aren't always, done digitally. Eric Jacobsen Anchor Hill Communications http://www.anchorhill.com
Reply by ●June 9, 20132013-06-09
Sir, thanks a lot. Yes, I was mainly referring to the pilot sequence. But can you let me know what you mean by controlling in digital domain (in baseband) since all it contains encoded data. Thank, manish>
Reply by ●June 9, 20132013-06-09
On Sun, 09 Jun 2013 12:05:41 -0500, "manishp" <58525@dsprelated> wrote:>Sir, thanks a lot. Yes, I was mainly referring to the pilot sequence. >But can you let me know what you mean by controlling in digital domain (in >baseband) since all it contains encoded data. > >Thank, manishThe transmit waveform is PCM, like most signals, so pilot symbols can be amplified numerically compared to non-pilot symbols during modulation. For a single-carrier waveform this would most likely be done just prior to transmit pulse filtering. For a multi-carrier (e.g., OFDM) waveform, this would be done to the subcarrier symbols prior to the FFT (or IFFT, depending on one's preference) before transmit. Eric Jacobsen Anchor Hill Communications http://www.anchorhill.com