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2007/03/05

TuneParam(&pPHY->RSSI_AGC);

IFでナニが通る事を確認.
次はRFでなのだが,小ロットで手に入るRFなチップの出来が低品質な為,
RSSI_AGCと呼んでいるブロックへの入出力に色々補正をしなければなら
ない事が発覚.
[Connected peer IF in/out.
Next is RF in/out tuning, but t3h suck0rz RF chip set is really
retarded. It's mandatory to some adjustment/correction.]

具体的にどの辺りが低品質かと言うと,制御入力が出力に筒抜けになる為,
目標値との偏差が大きい時の粗調段階でシステムが発振する. :(((
これにはテキトーな一次補正で対処.
[E.g. t3h RF chip set through its control input to plant output.
So, it makes hunting when error of targeted value is kinda mighty
in coarse adjustment phase. :(((
We needs to use one-loop correction for it.]

問題はここからで,復調部分にかなり高次のFIRフィルタを噛ませている
関係上,かなり遅れ時間が有る.しかもOFDM特有の時間領域でのトゲが
かなりウザい. :(((
FPGAの容量もギリギリなので二進重み付け平均で対処予定.
[The real subject is.
Part of OFDM demodulation has a high-order FIR filter, it has big
latencies. And then, generally, OFDM symbol in time domain has short
cycle peak. It's really annoying. :(((
I'd have to fix by using binary weighted moving average b/c the
FPGA's logic stuff's capacity limit.]

あとは適当にモニタ信号に色々突っ込んで順を追ってパラメータを調整して,
RFの個体差が誤差の範囲に入る事を祈るだけ. :P
[Well then, to pull some signals related this gain controller and
step by step paramter tuning is all I have to do.
Oh wait, I won't forget to pray t3h RF modules have no considerable
individual variability, though. :P]

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