To understand what Average power for one cycle means you must first realize
that
"RMS Power" is meaningless. What most are calling RMS power is Average power.
See my previous example.
73
Bill wa4lav
At 02:11 PM 11/7/2002 -0500, Joseph DiPietro wrote:
>The RMS power of an RF signal is a mathamatical approximation of the
>equivilant amount of DC power.
>
>For example, if an RF signal were to dissapate in a resistive load then the
>RMS value of that signal would model the amount of DC power needed to cause
>the same amount of heating in the load.
>
>I don't quite understand what PEP is supposed to be but according to
>http://www.its.bldrdoc.gov/fs-1037/dir-027/_3903.htm
>peak envelope power (of a radio transmitter) [PEP, pX, PX]: The average
>power supplied to the antenna transmission line by a transmitter during one
>radio frequency cycle at the crest of the modulation envelope taken under
>normal operating conditions. [NTIA] [RR] (188)
>
>JoeD
>N2UF
>
>----- Original Message -----
>From: <wb8jkr@juno.com>
>To: <Maximo.Martin@icm.siemens.com>
>Cc: <amps@contesting.com>
>Sent: Thursday, November 07, 2002 1:25 PM
>Subject: Re: [Amps] RMS-PEP & 2x8877
>
>
> >
> > The negative peak occurs 180 degrees away from the positive
> > peak, so they don't occur at the same time. You can't add them
> > together.
> > PEP power is the same power level as you would have KEY DOWN
> > at a given power level except whatever little extra you'd obtain
> > from power supply dynamics, typically 5 to 10 %.
> > A amp that runs 1000 watts output carrier is going to run 1000
> > watts PEP output plus maybe 5 to 10 % during SSB use, its
> > the average power that is going to vary considerably.
> >
> > Mark WB8JKR
> >
> >
> > On Thu, 7 Nov 2002 10:20:59 -0500 "Martin, Maximo"
> > <Maximo.Martin@icm.siemens.com> writes:
> > > RMS is an average measurement, efective power instead PEP, it's peak
> > > to
> > > peak.
> > > If you take one peak without flat-topping you have the RMS, but it
> > > is from
> > > the half of the total, in a graphic you use only the upper half part
> > > of the
> > > signal, but PEP is from the top peak to the bottom peak so it is
> > > more than
> > > double, it is 2.25 times.
> > >
> > > Max.
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: DF3KV@aol.com [mailto:DF3KV@aol.com]
> > > Sent: Thursday, November 07, 2002 9:52 AM
> > > To: Maximo.Martin@icm.siemens.com; amps@contesting.com
> > > Subject: Re: [Amps] RMS-PEP & 2x8877
> > >
> > >
> > > I
> > >
> > >
> > >
> > >
> > > 2 x 8877 are able to run about 4.5 to 5 Kw out, but this is a RMS
> > > measurement. The PEP value is the RMS x 2.25 so; 4.5 x 2.25= + 10000
> > > W
> > >
> > > Max.
> > >
> > >
> > >
> > >
> > > Hello Max,
> > >
> > > Please explain why PEP should equal 2,25 x RMS wattage?
> > >
> > > For my knowledge so far PEP ist the RMS wattage at the peak of the
> > > envelope without flat-topping.
> > >
> > > 73
> > > Peter
> > >
> > >
> > >
> > >
> > >
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