#### Gibson486

Joined Jul 20, 2012
336
DO I have this right....

In a 2 quad multiplying DAC, only one of your inputs (reference or the digital multiplication level) can be negative. So, if your digital level go from 0 to 255 (8 bit), then your signal on your reference can go from +V to -V. However, if you pick your reference to only go above 0V (no -V in your signal), then your digital code now does from -127 to +127. Also, this means that your output can never be centered at 0 if you use the "negative" digital code.

In 4 quad, both can be bipolar regardless of what the reference or digital code is. Also, the output can now be centered at 0.

My question is, what would be a use for a 4 quadrant? Or, when would you ever use a "negative" digital code in a 2 quadrant? The only thing I can think of is that you can get a signal of 180 phase for each digital code. It makes sense mathematically maybe (if centered at 0, you can now use all the unit circle stuff imaginary number stuff easily?), but there has to be other uses....