hello, I have a question.

I want to build a battery powered FM modulator for an aux audio device.
I want this device to be as high fidelity as possible, with fm stereo.
can you tell me how to build a circuit using FM mod. ICs with in-built precise tuning and decent sound?
I've built a simple transmitter using one transistor, a coil, caps etc from a project online i read.
i'm looking to make one that's more advanced that i can actually use to get HiFi to my radio.
of this is very low power, maybe a 9v battery as supply. can anyone give me some examples of an ' advanced ' IC based FM modulator?

 

Silicon Labs has some very good single chip transmitters -theSI4710 through Si4721. See the linked pdf presentation.

https://www.silabs.com/Marcom Documents/Resources/Si471x-presentation.pdf

 

You can buy a ready-made one on Ebay for less....
http://m.ebay.co.uk/itm/New-Wireles...%3A4f5c964015c0a7f8f44119d5fffe9114%7Ciid%3A2

 

Silicon Labs has some very good single chip transmitters -theSI4710 through Si4721. See the linked pdf presentation.

https://www.silabs.com/Marcom Documents/Resources/Si471x-presentation.pdf

thanks.

so this being a single chip solution, if i have a blank board and a SMD work station i can just solder this, the couple of capacitors it specifies and an antenna? how hard would it be to give it a battery and charging circuit?

 

You can buy a ready-made one on Ebay for less....
http://m.ebay.co.uk/itm/New-Wireless-Car-Kit-MP3-Player-FM-Transmitter-Radio-Modulator-USB-SD-Remote-/201490008078?hash=item2ee9bd880e:g:TWgAAOSwCQNWehjG&_trkparms=pageci%3A243b83bf-43ae-11e7-b60c-74dbd1802360%7Cparentrq%3A4f5c964015c0a7f8f44119d5fffe9114%7Ciid%3A2

true, but I would like to build one, just to see how good and reliable i can make it.
these cheap ones they have on ebay are generally very low quality and mono only. I doubt I could make a pro grade FM modulator in my basement, lol but I'd like to experiment with simple RF stuff like this.

 

Some ideas. though not heavily researched:

Battery Charger
http://www.es.co.th/Schemetic/PDF/MCP73831-2.PDF

Regiulator
http://www.es.co.th/Schemetic/PDF/MCP1702-MC.PDF

Plus the microcontroller of your choice to setup and manage the chip.

You might want to browse around the internet and look at some of the ingenious designs people around the world have developed.

Nicom Transmitter
www.3-mtr.info/manuals/NICOM/NT30new.pdf

bw broadcast tx5 transmitter
www.radikaltr.com/LeCatalogue/images/attachments/BWB%20TX5%20Manual.pdf

Plus many very good transmitters on personal websites. -have a look around.
http://www.3-mtr.info/manuals/NICOM/NT30new.pdf