# MOD Factor of D-VOR

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#### TRQ

##### Member
I have DSB D-VOR.

Anyone know the meaning of the formula of "AM Modulation factor" of D-VOR's "9960FM".

When i know RF Power of Carrier[Pc] and each Subcarrier(Upper Sin[Pus], Upper Cos[Puc], Lower Sin[Pls], Lower Cos[Plc]).
and each value is as follows...
Pc=200 [W rms]
Pus=5 [W rms]
Puc=5 [W rms]
Pls=5 [W rms]
Plc=5 [W rms]

M9960={(Pus + Puc + Pls + Plc)/Pc)*F}^(1/2)

F=&#951;*((PI^2)/8)
&#951;=Distributor efficiency=77[%]
F=0.945

I think it means,
m=2*(Ps/Pc)^(1/2)
Ps=(1/4)*(Pus + Puc + Pls + Plc)
and, subcarrier is Modulated in space, so &#951; is multiplied.

but, I dont know what does (PI^2)/8 mean,
(... I guess it means Square root of Form Factor of sine wave)

Anyone know Why is it multiplied (PI^2)/8?
each Power value is root mean square value.

-----
I'm sorry for using confused English.

#### wa8vzq

##### Member
TRQ - sent a private mesage for you with explaination on this subject. Log back into RR and read your messages.

#### TRQ

##### Member
wa8vzq
Thanks for PM. I read the message and replied it!

#### n2nov

Well now that my curiosity is up on the method of modulation and the structure of the transmission, why not share with everyone?

#### TRQ

##### Member
Conclusion(?)

I exchanged PM several times with wa8vzq, and he told me about VOR theory.
Now, I write the my conclusion of this topic.

Formula that I presented before might be correct.
and (PI^2)/8 might be calibration factor of SB RF Power.
because VOR SB is not simple sine wave(sometimes called CW).It's like Double balanced modulation of 720Hz.(This is for japan)
(and Ideal shape is "(sin x)/x". but this is not Continuousness, so it's very difficult to make this wave by real Transmitter. but by using ROM can...omission:wink:

So,This calibration factor is used to calculate the RMS(or avg) of SB power.

Though it was not settled well, I think that I end by this.

Thanks for being interested!

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