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<DIV><FONT size=2 face=Calibri>Yes, the multiplex signal itself is one size
fits all. The 'couple of stations' does refer to economic factors
rather than technical. For 10 stations each with a budget of (say) £1m
sharing a 10kW transmitter the cost equation is a bit different from from a
couple of stations each with, say, £30,000 budget buying a 100W
transmitter.</FONT></DIV>
<DIV><FONT size=2 face=Calibri></FONT> </DIV>
<DIV><FONT size=2 face=Calibri>The old first-principles way of measuring the
average rms power of any arbitrary signal is to feed it into a
resistive load and measure how much heat it generates. But more usually
nowadays, spectrum analyzers, which are needed anyway for commissioning a
broadcast transmitter, can easily measure the total rms power of a signal
at an instant or averaged over time. Often there is an add-on pack for
spectrum analyzers that contains extra bits (such as a directional coupler/SWR
bridge and extra software) that calculates the various radio-related parameters
such as power, spectral occupancy, out-of-band harmonics etc. </FONT></DIV>
<DIV><FONT size=2 face=Calibri></FONT> </DIV>
<DIV><FONT size=2 face=Calibri>And for all I know the digital signal processors
in the SDR can also calculate the average total power at the same
time as they are doing all the amazing on the fly maths to create the signal in
the first place - just a little bit more arithmetic for them to do on the
side!</FONT></DIV>
<DIV><FONT size=2 face=Calibri></FONT> </DIV>
<DIV><FONT size=2 face=Calibri>Alex</FONT></DIV>
<DIV><FONT size=2 face=Calibri></FONT> </DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=ravensound@pilgrimsound.co.uk
href="mailto:ravensound@pilgrimsound.co.uk">Tony Bailey</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=tlr@gairloch.co.uk
href="mailto:tlr@gairloch.co.uk">tlr@gairloch.co.uk</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, March 10, 2015 3:45
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [cma-l] DAB trials</DIV>
<DIV><FONT size=2 face=Calibri></FONT><FONT size=2
face=Calibri></FONT><BR></DIV>
<DIV class=moz-cite-prefix>Thanks,<BR><BR>Arising from that (without boring
the readers!) I was under the impression that the mpex carrier was one lump,
i. e. independent of the number of programme feeds, so presumably the "couple
of stations" is an economic rather than technical factor? How do you
arrive at an average power figure for 1500 parallel carriers any of which
could presumably be zero or 100%?
<BR><BR>Tony<BR></DIV></BLOCKQUOTE></BODY></HTML>