[sdiy] digital noise band generator?

[Paul Perry]

Thanks for the responses so far.
I have had a vision - a white noise source through an adjustable LP filter 
at frequency F1 fed to a ring modulator, with a sine oscillator frequency F2 
to the other input.
If I am correct, and assuming the LP filter goes to zero frequency, then the 
modulator output will be a noise band of (F1-0) width on both sides of F2.

How bad the notching in the middle will be (due to not being able to get to 
zero freq) will be, I cannot say. But I think it might do for experimenting. 
Wish I had one of those ring modulators I used to make..

paul perry Melbourne Australia