Radio scan controller?

[Scott Gravenhorst]

Plinio Andres Barraza <pab210 at is8.nyu.edu> wrote:

>I remember a while back a discussion about switched capacitors, someone
>mentioned they were on the way to being digital.  Are switched capacitors 
>devices that do the equivalent of laying down a series of capacitors of
>different values and just switching between them?     

Switched capacitors are normally used in an RC tuned circuit.  The capacitor
is switched in and out of the circuit with a clock signal.  The duty cycle
of the clock controls the effective capacitance.  I don't know how that
would effect the tuning of an LC resonant circuit since both the L and the C
are storage elements, where as in an RC circuit, only the C is.  If it worked
at all, I think the clock for the C would have to be much higher, like twice
the frequency of the LC circuit.

-- Scott Gravenhorst
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