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Hello, i need formula for if IF transformer 42IF123-RC to design in ltspice

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Hello

can somebody help me
for IF transformer
42IF123-RC i need to resonate at 10.7Mhz, i want to design in Ltspice

i read one Post here, but i dont understand
i dont know the formula, for inductor in ltspice
Naamloos.png

here my circuit in ltspice
IF.png
 
118820

The capacitor is 4.7pF + 5pF = 5.2pF
From 1-3 is 4.5uH (3.2 to 5.7uH)
There is no 4k resistor inside.
1-2 = 5 turns
2-3 = 9 turns
1-3 = 14 turns 4.5uH
4=6 = 2 turns
The formula for inductance and turns ratio is turns^2 (turns squared)
We know that 14 turns = 4.5uH.
You need to work out the inductance for 1-2, 2-3, and 4-6. Then plug them into spice.
You have the phasing of 1-2 & 2-3 so the inductance will add not substract so that is good.

I hope this helps. RonS.
 
Hello Rons
thanks for help
i realy dont understand

PLEASE can you show me one example?
i dont want to bother nobody here

so 1-3 is 4.5uH, come 14 turns = 4.5uH
i get 4.5uH ^ 2 we get 2025uh

I rely dont know, how come 14 TURNS = 4.5uH

:banghead:
oh man can you show me example please...……..

thanks
 
There are 14 turns between pins 1 and 3. Per the datasheet there is 4.5uH between pins 1 and 3.
There are 5 turns between pins 1 and 2, so the inductance between those pins will be 4.5uH x (5/14)^2 = 4.5uH x 0.128 = 0.57uH.
 
ooh thanks Alec_t
perfect MAN, i understand now

:)and wat about 4-6(2 turns) how i have to calculate this one ? please if you know let me know and i go to build...……..


is like this correct 4.5u / (14/2)^2 = 0.9uH
 
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This is the first time I have ever seen somebody try to simulate an FM radio. Why????
 
This is the first time I have ever seen somebody try to simulate an FM radio. Why????
Because turning the "on" knob is hard. lol

I have often SPICE-ed the IF filters to get the bandwidth right. Probably I have done every block of a FM radio many times but never the entire thing.
One thing, I do not have enough computer to do the entire radio. I started with SPICE on a 8088 PC and "if my computer was a little faster". Now with 1000x faster it is too slow.
 
The crystal filter defines the bandwidth. The simulation program does not know about crystal filters.
 
The crystal filter defines the bandwidth. The simulation program does not know about crystal filters.
What crystal filter?
I think we have exceeded the scope of the question. We just needed to go from data sheet to spice model.
 
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