chaoseverlasting
- 1,051
- 3
I've been working on a guitar effects project for a while and I need a little help. What I want to do is add even harmonics to the signal. The way I've gone about it is this:
I've used a diode to add harmonics to the signal. At very low volatages (<1v) the diode current may be approximated as [tex]ax+a_2x^2+...[/tex] where x is the input signal of frequency w.
Then I've used a low pass filter to filter out the higher frequency components (greater than 2w).
Since the above expansion for diode current comes from the taylor series of the diode equation, a=1.
I've then used a differential amplifier to remove the original input (x) to get the [tex]x^2[/tex] term only, which I put through another diode to get my even harmonics.
The problem is, I don't know how accurate or effective this method will be. I've lost my Pspice cd and I don't want to build this thing only to find out that it doesn't quite work.
For the diode equation, here's a wiki link:
http://en.wikipedia.org/wiki/Diode
The equation is about half way down the page.
I've used a diode to add harmonics to the signal. At very low volatages (<1v) the diode current may be approximated as [tex]ax+a_2x^2+...[/tex] where x is the input signal of frequency w.
Then I've used a low pass filter to filter out the higher frequency components (greater than 2w).
Since the above expansion for diode current comes from the taylor series of the diode equation, a=1.
I've then used a differential amplifier to remove the original input (x) to get the [tex]x^2[/tex] term only, which I put through another diode to get my even harmonics.
The problem is, I don't know how accurate or effective this method will be. I've lost my Pspice cd and I don't want to build this thing only to find out that it doesn't quite work.
For the diode equation, here's a wiki link:
http://en.wikipedia.org/wiki/Diode
The equation is about half way down the page.