wave form

I thought at first to use a VCO, but I didn't found any that generates a sine wave with 500Khz. So I thought to use a microcontroller, like Atmel o Arduino, but it's really difficult to create a PWM greater than 4MHz. Do you know any other way to generate a sine wave?

Hello, I wondered about what would happen if I feed a 20KHz square wave, that goes from 0V to 5V, through a bandpass filter. Does it filter out the DC part and the only part that's left is a square wave oscillating from -2.5V to 2.5V ? And if that's the case, where does the "negative" voltage...

Hi! I've built a CDN (Coupling/decoupling network) and when connecting it to a Surge generator the wave form gets a little distorted, the fall time becomes half of what the Surge pulse produces. I'm new to designing circuits and am not really sure what components to tweak and how. The image...