The circuit shown here is of a quality Stereo FM transmitter that might transmit high quality signals up to a variety of 70 feet. The circuit is Depending on BH1417 PLL stereo transmitter IC in one Rhom semiconductors. The IC has separate audio processing sections towards the left and right channels, pre emphasis circuit for improving signal to noise ratio, crystal control circuitry for accurate frequency locking, multiplex circuit for and make sum ( left plus right) and difference ( left minus right).
Another important feature of this IC is that the transmission frequency seem like either set utilizing a 4 channel DIP switch. The IC seem like either powered in one anything between 4 to 6V DC and comes with other an output power around 20mW. At full output power the circuit consumes only 20mA and has a channel separation of 40dB. There {seem to be|appear to be|are} 14 possible preset transmission frequencies, starting in one 88.7MHz and incrementing in steps of 0.2MHz Which is going to be selected utilizing the DIP switch. The PLL circuitry of those IC is so precise that There's almost no frequency drift.
