[ICOM] Shaft Encoder vs pot?

[Augie Hansen]

ken.holland at evonik.com wrote:
> Just a short question here, what is the difference in a *shaft encoder* (as
> used in the 756 Pro PBT encoder) and a "variable resistor" or pot?  I have
> wondered that when turning the volume knob on car radios - they seem to
> have many little "detents" as you turn the knob.  Just what info is being
> sent to the processor?  Pots I understand, but not *encoders*.
>   

A shaft encoder (or rotary encoder) of the type used in our radio 
equipment is typically an electro-mechanical or optical mechanism that 
converts shaft rotation into a series of pulses. Those pulses can be 
interpreted as an increase or decrease in some parameter, such as audio 
level, frequency, etc.

Have a look at the following Web page to get some background on the topic:

    http://en.wikipedia.org/wiki/Rotary_encoder

Gus Hansen
KB0YH