highspeed PWM

I just got my Uno and am trying to generate highspeed PWM signals (> 5kbps or 20000 transitions per sec) it looks like the standard PWM protocals to not react fast enought but the Softwareserial Library would have the throughput has anyone had success in boosting PWM or taking a standard serial signal and converting to a PWM using another board

The 8-bit Timer/Counter on a 16 MHz Arduino should be able to do 8-bit PWM at 62.5 KHz (16 MHz / 256).

Using pre-scale values of 8, 64, 256, and 1024 you can get 7.8125 KHz, 976.5 Hz, 244.1 Hz, or 61 Hz.

With a 16-bit counter you can get much better control over the frequency if you want a more precise frequency.

If you don't need 256 levels of PWM you can get even higher frequencies.