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Вся теория AGC может быть изложена коротко.
Я много парился, в конце концов сделал отличный AGC из пяти строчек, по типу приведенного ниже. Если есть голова - сможете улучшить модель под Ваши требования.
Assume yin is the input to the AGC (say a speech signal) and yout is the AGC output.
loop forever
{
/* Voltage controlled amplifier is just a multiplier here */
yout=yin*iout
/* error */
err=spoint-abs(yout)
/* Integrate */
iout1=iout
iout=iout1+gain*err
}
The gain needs to found by trial and error. If gain is too big you will get instability
and if too small it will be too slow to respond. try gain=0.001 for starters and increase it. In fact the gain limit is a function of the size of yin. spoint = 1 will do for a set-point.
All an AGC is is a voltage controlled amplifier (a multiplier here), a rectifier, a setpoint and a low-pass filter. The filter here is an integrator so as to get zero steady-state errror to a step change in
amplitude. If you wnat to get fancy you can have two integrators and phase-lead compensator though it is difficult to keep stable for large dynamic ranges.
Спасибо ребятам из comp.dsp
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info@telesys.ru
