If you store charge [DC] with an amplitude and polarity which
corresponds to the instantaneous input AC, then you will have to
sample, so the short answer to your question is: "It can't be done."
Is there any workaround so that sampling won't be necessary?
Okay so sampling is a *must*. But can this sampling be done without
using PAM, PWM, or any carrier waves? Can't the charges be sampled in
the capacitors without adding any sort of modulation to them? If not,
they why?
---
As Bob Masta said: "Huh? Whatever are you going on about *now*?"
Here's what sampling is: Let's say that you have a 1000Hz 1VPP sine
wave of which you want to store one cycle and that you've got 360
capacitors on hand.
Then you might do something like this:
A B
ACIN>--O--> | <---------------------->OUT
| S2 1
S1 O---O--->O----------+
C C |
2 O------+ [C1]
. | |
. [C2] |
. | |
360 O--+ | |
| | |
[C360] | |
| | |
GND>--------------------+---+---+---->GND
S1 is a SPDT center-off analog switch of some kind and S2 is a 360
channel break-before-make analog switch. In order to store the
waveform what you do is start with S2 in position 1, very briefly
connect S1C to S1A, then return S1 to the OFF position. This will
charge C1 (Which is a tiny sample-and-hold cap) up to the voltage
of the input signal, more or less.
Once that's done, S2C is connected to S2-2 and the input signal
sampled again.
After 360 samples have been taken, S2 is is placed in the '1'
position, S2 is placed in the 'B' position, and S1 made to traverse
S1-1 through S1-360 at the same rate as when the samples were taken.
When that's done, the voltages each capacitor has been charged to
will be presented at "OUT" sequentially, recreating the input
waveform with only very light low pass filtering required between
the different output samples.
What I've shown you is _very_ rudimentary, and there needs to be a
mechanism employed to discharge the caps, which I haven't shown, but
which I'm sure you can find if you Google "sample and hold"