YMU759B

FM synthesizer functions
·Tones
FM synthesizer is capable of creating countless tones theoretically. When synthesizing tones, it is necessary to designate the number of operators to be used for the synthesis. Increasing the number of operators allows synthesis of tones that are more intricate and closer to those generated by natural musical instruments.

YMU759B supports synthesis of tones of two types including 2-operator tones and 4-operator tones. Because operator's wave shape can be chosen from eight kinds, the quality of sound improves more remarkably than 2 operator sound of the MA-1 series. (A MA-1 series can choose operator wave shape from two kinds.)

YMU759B is a synthesis LSI for portable telephone that is capable of playing high quality music by utilizing FM Synthesizer and ADPCM decorder that are included in this device. As a synthesis, YMU759B is equipped with Yamaha's original FM synthesizer, with which the device is capable of simultaneously generating up to 16 voices with different tones. Since the device is capable of generating ADPCM data simultaneously synchronous with the play of the FM synthesizer, various sampled voices can be used as sound effects. Since the play data of YMU759B are interpreted at anytime through FIFO, the length of the data (playing period) is not limited, so the device can flexibly support applications such as incoming call melody distribution service. The hardware sequencer built in this device allows playing of complex music without giving excessive load to the CPU of the portable telephones. Moreover, the registers of the FM synthesizer can be operated directly for real time sound generation, allowing, for example, utilization of various sound effects when using the game software installed in the portable telephone.

YMU759B includes a speaker amplifier with low ripple whose maximum output is 550 mW (SPVDD=3.6V). The device is also equipped with conventional functions including a vibrator and a circuit for
controlling LEDs synchronous with music.
For the headphone, it is provided with a stereophonic analog output terminal. For the purpose of enabling YMU759B to demonstrate its full capabilities, Yamaha proposes to use "SMAF: Synthetic music Mobile Application Format" as a data distribution format that is compatible with multimedia. Since the SMAF takes a structure that sets importance on the synchronization between sound and images, various contents can be written into it including incoming call melody with words that can be used for training karaoke, and commercial channel that combines texts, images and sounds, and others. The hardware sequencer of YMU759B directly interprets and plays blocks relevant to systhesis (playing music and reproducing ADPCM with FM synthesizer) that are included in the data distributed in SMAF.