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VE2HAR > MT63 13.03.05 17:05l 60 Lines 1816 Bytes #-7304 (0) @ WW
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Subj: Re: [MT63] Re: Crest Factors
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Sent: 050313/1548z @:VE2HAR.#MTL.QC.CAN.NOAM Laval #:42139 $:38182sentto
Another couple of crest factor definitions from RFDESIGN magazine at
http://rfdesign.com/mag/radio_crest_factor_analysis/
Peak crest factor
This is the ratio of the instantaneous peak voltage squared to the average
output power, but for translated signals (IF or RF) it is customary to
consider the crest factor for the envelope signal. Because most RF devices
are characterized with sinusoidal signals at either specified or measured
power levels, having the crest factor as a function of a sinusoidal
signal's power level is more appropriate.
Envelope crest factor
To determine the envelope crest factor, first determine the power of a
sinusoidal signal that has the same peak voltage as the modulated signal's
peak voltage. This value is then divided by the average power of the
modulated signal. The result is defined as the translated signal's envelope
crest factor.
It seems I was measuring peak crest factor. Envelope crest factor or PEP
to average ratio is 5.14, so lets call it 5, and the crest factor is 2.2,
or 7 dB.
73,
Mark N5RFX
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