With a competent PWM generator on a microcontroller, you can create this carrier modulation easily enough yourself. Set the PWM frequency to 38 kHz and the duty cycle somewhere in the 33%-50% ...

On a microcontroller, though ... an output on while the CPU is busy and then turn it off again when idle, a PWM signal with a duty cycle proportional to the CPU load is created.

The microcontrollers are equipped with an array of peripherals, including PWM generators, counters/timers, EUSART serial bus controllers, and MSSP modules for I2C or SPI operation. They also feature ...