For the Red Pitaya, there is a fully worked-out example of a software defined radio
that makes use of predistortion. It is said to remove the detrimental effects of the
power amplifier.
I did not dive into it, but, since the RP has two 125 MHz DACs and ADCs, I suppose
they re-digitize the own aired signal and transmogrify the input until the received
signal looks like it is supposed to look.
In the end, predistortion is just like feedback if you want success control.
If do not need success control and only need buzzwords to betray the
feedback-is-bad-crowd, you can trim it once and hope that temperature,
humidity, input signal, load and the phase of the moon do not change.
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Look like we need a new thread for drivers too.
And honestly, if it will come to the level in this thread, will not be such a bad idea.
Then after, we need to figure out what to do to be able to find reasonable priced and large offer of HD-files copies, old style move as back in the RTR times
And honestly, if it will come to the level in this thread, will not be such a bad idea.
Then after, we need to figure out what to do to be able to find reasonable priced and large offer of HD-files copies, old style move as back in the RTR times
The biggest advantage of current drive is, that drivers use it natively.
The biggest disadvantage of current drive is, that drivers use it natively.
The opposite is true for voltage drive as well.
Choose your poison
Surely some will mix it, no question. But that's fine too, any case, if results are worth the effort.
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Yes. Some 35 years ago I made some experiments with modding the TS parameters
of a chassis with a system that cancelled the coil resistance with a negative
impedance driver after St°ol. It is surprising how low you can go, frequency-wise
with a small driver when you make compromises vs. SPL.
But the driver is not even time-invariant. With a hot coil after some drum pulses
it looks completely different. At room temp., ohmic resistance of a 8 ohm speaker
is abt. 3 Ohms, but when is is hot, it is much more. Not the right precondition if you
want to cancel it with a negative resistance that is fixed.
Subtracting 'alike' values to get 0 is doomed.
Gerhard
(who has accepted that B&W know more about speakers than me, but who is
happy abt. the result. Yes, it DID hurt my pocket. But not yet another front! )
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Breaking the loop at the appropriate point in the circuit in order to characterize the response and the phase of the tank.
Doesn't this happen to everyone? No?
Well, it shows that your amplifier (mostly but speakers can ruin it too) has a low noise floor and low crossover distortion...
It's still very early in the morning (4:45) here. I woke up and enjoyed that low level detail from my system for hours now...
Isn't this related well with output topology used by many zero feedback class-B amplifiers?
Yes, the positive feedback loop.
It's a Driscoll oscillator, the CLC tank wich resonates at the overtone crystal frequency and suppress the fundamental and the unwanted B-Mode.
The tank has a relatively high Q so has to be tuned to get the oscillator starting.
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