Rohm BH1418FV FM transmitter

bh1418fv

Hi,

Has anyone an example schematic for the BH1418FV Stereo FM transmitter from Rohm ?
I managed to get one but there is no sample schematic in the Datasheet.

Thnx,
Nathan

bh1418fv schematic

Looks to be functionally the same as BH1415 which data and application can be found here
**broken link removed**

bh1418fv fm transmitter

Thnx,

Just wat i needed.

Regards,
Nathan

bh1418fv circuit

My experience with these ROHM chips is that the internal audio lowpass filter does not have enough poles, so I would add another 2 poles of audio 15 KHz lowpass filtering to each audio input.

Also, the chip is easily overloaded by high dynamic range signals, like a CD player. A soft audio limiter circuit will allow you to keep the FM deviation high for good SNR, but also handle thundering audio passages without bad distortion.

fm rohm

Hi,

>>My experience with these ROHM chips is that the internal audio lowpass filter >>does not have enough poles, so I would add another 2 poles of audio 15 KHz >>lowpass filtering to each audio input.

Thnx... ill look in to that ..

>>Also, the chip is easily overloaded by high dynamic range signals, like a CD >>player. A soft audio limiter circuit will allow you to keep the FM deviation high >>for good SNR, but also handle thundering audio passages without bad distortion.

I want to use the transmitter on my yampp mp3 player www.yampp.com
So if i adjust the output level of all of my mp3's there would not be an problem.

The hardest challenge will be the coding, in C for use with the yampp 3 and in Bascom for use with various of other projects.

Thnx for your input.

Nathan

bh1418fv rohm

Yeah, MP3 files are soooo compressed, you will not have an audio dynamic range problem. You will have to tweak up the audio gain to be optimized, however.