I probably didn't explain myself very well (for the sake of simplicity) - I can see that you've probvably not sussed what I'm trying to achieve!
So, a little more meat on the bones...
I'm intending 'tapping' off a guitar signal (six signals actually...one from each string)...I need the 'level of the output of these six strings monitored. I originally implied having the PIC carry out this monitoring on the alternating guitar signal, but it makes more sense to do the following...
Since these six signals will be buffered (and will likely be amplified a little), I could actually turn them into a DC level with a full wave rectifier & smoothing cap...so I don't need any massive A/D processing...a simple sample of the string's DC level about 5 times per second should suffice.
I need the PIC here to act as a DC voltage comparator....let's say the rectified/extracted DC level of a particular incoming guitar signal is 2V, but it needs to be 3V...therefore we get the PIC to increase a DC level on an output pin (this feeds a DC 'volume control' pin on a power amp IC, this elevated DC will make the power amp 'drive' a guitar string sustainer coil more, which in turn makes the string vibrate more...the 'increased' guitar output signal is fed back into my circuit.
Thererefore, what we have is a feedback loop....if the incoming guitar signal is too low, the corresponding guitar string will be 'driven more' until its amplitude is increased & it hit's the target reference voltage.
I know all of this can be done in analog, but I'd like the circuitboard to go inside the guitar, so small size is paramount & a PIC with say IO 20 pins is an awful lot smaller than the several opamps per sting needed to do this.
So what I really need is a PIC to monitor 6 x DC levels against a reference voltage & subsequently change a DC output level on six of its output pins to suit. (ie I don't need any fancy logarithmic algorithms, etc)
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