The document describes a function called Init_PWM() that is used to configure 3 pulse width modulation signals using Timer B on an MSP430 microcontroller. The function sets up the timer control register TB0CTL to use the ACLK clock source and up counting mode. It also configures the compare capture registers TB0CCTL2, TB0CCTL3, and TB0CCTL4 to load the compare registers when the timer counts to 0 and use reset/set output mode. Additionally, it defines the pulse period using TB0CCR0 at 100Hz as specified in the header file, and configures ports P2.2, P3.6, and P3.7 as PWM outputs in secondary