PCS-Electronics

I tried to build a FM Reveiver according to the given schematic (http://www.pcs-electronics.com/schematics/Tda7000Rx.jpg).
The frequency adjustment doesnt work and i think i know why:
It seems that the whole oscillating circuit is wrong. The 22k potentiometer is between the +5V and 0V and the output only goes to a 1uF Capacitor. So it doesnt have something to do with the frequency....

Am i right?

My solution was a redesign of this part: the output of the potentiometer goes between the varicap diode and the 10nF Capacitor. I also connected the whole ocillation circuit to +5V instead of 0V.
If somebody wants to see my solution, please tell me and i make a scan.

Christian

You're right. Had a look at the jpg and its not right.

Can you make a scan with your corrected solution?
I will update the pic on the website.

Thanks for pointing this out, missed this error.

Hi!

No problem...
Here is the the corrected schematic, which works great for me:



Christian

I wanna build a fm reciver by TDA7000, but i want to simulate it with a software,how i can do that?can i do that with orcad?

You need spice model first for tda7000 and I don't think you'll get one.

In short, forget about simulating a complex IC like this.

Start by simulating simple circuits.