FM stereo transmitter assembly costs by BH1415F relatively cheap because all parts FM stereo transmitter has been included in the IC BH1415F. The chip consist of oscillators, pll, pre-emphasis, limitter, low pass filter, and a stereo FM modulator. FM transmission signal is very stable because it has been using a PLL system with serial input data (CE, CK, DA). Power output of BH1415F reinforced with several transistors and RD15HVF1 as the final amplifier so the circuits can produce a power output up to 15W.
15W stereo FM transmitter scheme using BH1415F & RD15HVF1 can be found here: