A FM-radio transmitter concept based on an all-digital PLL

A stereo FM-radio transmitter with Radio Data System (RDS) support based on an all-digital PLL is presented. It has been designed as a fully integrated single-chip transmitter in a 90-nm CMOS technology to be compatible with digital deepsubmicrometer processes. Target application of the proposed system is the cointegration with baseband processors and transmitters for mobile communication systems. Nowadays mobile phones have a lot of multimedia capabilities e. g. an integrated MP3 player. The proposed transmitter enables a mobile device to stream audio data to a FM receiver which is popular and existing in most households world wide. RDS support allows to send additional information e. g. title and artist of a song. As mobile applications are the main target for the transmitter great attention has been attached to saving power and area. Therefore, the presented transmitter works on a 1V supply voltage and is aimed for using a 32.768 kHz reference crystal oscillator instead of the commonly used 26MHz reference oscillator while still providing wideband frequency modulation capability.