ÓÑÈËÈÒÅËÜ ÌÎÙÍÎÑÒÈ ÈÌÏÓËÜÑÍÛÉ


         

ÓÑÈËÈÒÅËÜ ÌÎÙÍÎÑÒÈ ÈÌÏÓËÜÑÍÛÉ - ÷àñòü 5


 êÎì.                                                

4.5 Ðàñ÷¸ò íåêîððåêòèðîâàííîãî êàñêàäà

Ýëåêòðè÷åñêàÿ ñõåìà íåêîððåêòèðîâàííîãî êàñêàäà èçîáðàæåíà íà ðèñ.(4.4).

 


     Åï

                                                                  RÁ1                                       RÊ

                                                             a                                                CP

                                            CP

                                                                  RÁ2                                       RÝ                       ÑÝ                  RH

Ðèñóíîê 4.4 – Ñõåìà íåêîððåêòèðîâàííîãî êàñêàäà

Ïåðåéä¸ì ê îäíîíàïðàâëåííîé ìîäåëè (ñì. ðèñ.4.5). Íà ñõåìå   GÝÊ = gi + gH.

Ðèñóíîê 4.5 – Îäíîíàïðàâëåííàÿ ìîäåëü áèïîëÿðíîãî òðàíçèñòîðà

1) Ðàññ÷èòàåì êîýôôèöèåíò óñèëåíèÿ íà ñðåäíèõ ÷àñòîòàõ  Ê0:

Ê0 = S0 RÝÊÂ,                                                               (4.21)

ãäå

;                                                       (4.22)

*
,
,
  - ïàðàìåòðû ñõåìû çàìåùåíèÿ Äæèàêîëëåòî.

Ïîñëå ïîäñòàíîâêè ÷èñëåííûõ çíà÷åíèé, ïîëó÷èì

25 Îì;                                                                 

;                                                

.                                                           

Îöåíèì òðåáóåìîå  çíà÷åíèå  ïîñòîÿííîé  âðåìåíè êàñêàäà â îáëàñòè Â× (ìàëûõ âðåìåí) äëÿ ÈÓ, ïðåäïîëàãàÿ âðåìÿ óñòàíîâëåíèÿ ýòîãî êàñêàäà:

ñ.                                                                         

 ñ.                                          (4.23)

Ðàññ÷èòàåì îæèäàåìîå çíà÷åíèå ïîñòîÿííîé âðåìåíè êàñêàäà â îáëàñòè âåðõíèõ ÷àñòîò (ìàëûõ âðåìåí).

           (4.24)

Åñëè

,                                                                 (4.25)

òî îæèäàåìûå èñêàæåíèÿ áóäóò íå áîëåå çàäàííûõ.

Âèäèì, ÷òî âðåìåííûå óäîâëåòâîðÿþò òðåáîâàíèÿì ê ðàññ÷èòûâàåìîìó óñèëèòåëþ, ò.å. âðåìÿ óñòàíîâëåíèÿ ôðîíòà èìïóëüñà ìåíüøå êðèòè÷åñêîãî çíà÷åíèÿ




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