Hello everyone,

First of all sorry for my bad english.

I want to simulate on Proteus FM demodulation with 4046.
I know that the center frequency Fo depends on the value of R1 and C1.
I try to do this application circuit and it doesn't work too:

I try to change the value of Fo according to the following curves:

I conclude that the problem on proteus is from that part that change everythings and i don't understand how to control it :
"Frequency Range" and "Frequency offset" in "Advanced Propreties"

I look at anywhere and i don't know why !!!
I'm loosing my head ^^

Thank you in advance!

 

Hello,

It looks like you are using this part of the datasheet:

Did you use a modulated 10 KHz signal ?

Bertus

 

Yes I use this part.

In real life on breadboard I make the circuit with C1 and so a Fo of 14kHz.
The low pass filter on the circuit above is not good for a modulation of 400Hz becaus the Fc of the low pass filter is around 159Hz.
So I modify my Signal In FM og 14kHz with modulation of 100Hz.
The demodulation works great and I obtaine my 100Hz in modulation on pin 10.

For the simulation I finally discover what is frequency range and what is frequency offset:
- Frequency offset is: Fmin
- Frequency Range is: Fmax

For this observation I only used the VCO. I modify the voltage on VCO In and look at the frequency on VCO out. In the same time in Propreties I modify Frequency Range and Frequency offset. When i put the voltage at 0V(Fmin), i have on VCO Output the value of frequency offset(1kHz). When i put the voltage of VDD(here i choose 5V), i have on VCO Output the value of frequency Range(600kHz).

BUT despite of that the output of demodulation is not ok like in real life.

If anyone have the answer, he is welcome.
I look at on the internet and lot of people are asking what is frequency range and frequency offset on PROTEUS.
The response is here !
- Frequency offset is: Fmin
- Frequency Range is: Fmax