Sun Dec 26 13:10:45 EST 2010
Current conversion, frequency feedback
Problem: building a lin -> exp converter to be used in an oscillator
requires temperature stabilization. It might be simplest to do this
closed-loop. However, this requires a large resolution.
The only large resolution available on a cheap uC is time, so it might
be a good idea to convert the output current to a variable frequency
circuit: i.e. to add a relaxation oscillator to each exp output circuit.
- The exp converter current is most likely used to set the bias
current in a differential pair. How much voltage can we use and
does this feed through to the signal (CMRR?).