CAn anyone help me? I want to build an FM Rx with TDA7000!!

pe1jpd

Hi all,
I want you to help me to build a high bit rate Rx using TDA7000.. I could build the Rx as described in its datasheet, but it allow bit rate not higher than 9kbps

I want to increase its bit rate.. I think that reason of that low bit rate is due to that last low pass action made by last AF stage, Can I overcome this problem if i added in cascade another HPF with opposite c/cs to the latter LPF?

Is there any other modifications that i can made??

Please help me, I am in trouble!!!!
And any information will be appreciated..
You can find TDA7000 Datasheet here:

**broken link removed**


Thanks alot in advance,
Ahmad,
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tda7000 ham

The TDA7000 is a complete radio circuit and it doesn't look like you can "modify" it to achieve higher bit rate ..
You can try to "play" with the loop filter capacitance but that's more the less it ..

Regards,
IanP

Re: CAn anyone help me? I want to build an FM Rx with TDA700

Try to use demodulated signal from pin 4
just unsolder condensator from Vpp line, youll get nice unfiltered demodulated
signal.
Maybe afc will be problem, you have to try.
Or use TDA7021 (KA22429) and demodulated signal from pin 1

Re: CAn anyone help me? I want to build an FM Rx with TDA700

IanP said:

The TDA7000 is a complete radio circuit and it doesn't look like you can "modify" it to achieve higher bit rate ..
You can try to "play" with the loop filter capacitance but that's more the less it ..

Regards,
IanP

Click to expand...

Hello IanP
How can I play with loop filter although it's embedded inside the IC and i have no pin out to access it..

also, what does the noise source do? I want to understand it as well as the mute circuit...

Final thing, I want to simulate the TDA7000, Can you (or anyone) help me to model it? I dont care which tool i will use, i may be able to use either OrCAD or A.D.S.. if anyother tool you suggest, it will be also appreciated..

Thank you very much..
Ahmad,

____________________________________________________________________
Added after 25 minutes:

hf2050 said:

Try to use demodulated signal from pin 4
just unsolder condensator from Vpp line, youll get nice unfiltered demodulated
signal.
Maybe afc will be problem, you have to try.
Or use TDA7021 (KA22429) and demodulated signal from pin 1

Click to expand...

Hello hf2050
Thank you for reply,
I hope your idea will succeed, but i think another problem may arise due to the IF filter, what about its BW limitations?? finally, can you help me to build a model to the TDA7000??

Regards,
Ahmad,

Re: CAn anyone help me? I want to build an FM Rx with TDA700

Lets say IF is on 70Khz and it is 100Khz(+-) wide, you can use simple
Manchester coding modem and youll get 19200-38400bps.

**broken link removed**
**broken link removed**
http://www.qsl.net/ok0ns/technics.html#ManModem
http://www.qsl.net/yo5ofh/projects/ham radio projects.htm
(TDA7000 FM receiver aplication notes and examples: page1, page2, page3, page4, page5, page6, page7, page8, page9, page10, page11)


And try google, WBFM packet-radio

Good luck !

Re: CAn anyone help me? I want to build an FM Rx with TDA700

Thank you for replying
But what is the language in that links? Tell me and i may be able to use any web translator site..

Or if there's an english version from it, it will be better,
Also, i don't fully understand, what should i code? i think that line coding is made at the Tx end as well as Rx end, is that links contains both Tx and Rx sides,

Thanks, and keep helping,
AHmad,