Convergence tirne
100D 2000 2.500
2500
Hinh 24. T i n hieu ECG sach (a), tin hieu bi nhiem can nhieu (b), tin hieu qua bo loc thich nghi (c), tin hieu qua loc ciia so t r u o l (d),
De danh gia hieu qua eiia bg Igc thieh nghi, s6 lieu vao d(n) duge thu ihap va eon duge linh theo eong thire xir ly ciia mgl bg Igc noi lieng la bg Ige post-time cua so trugt (dj. Ket qua eho thily, mac du mat mot thai gian hoi tu kha dai, nhung bg Igc
thich nghi eho dirge dang lin hieu ra eo dang sic net ban va khong bi meo dang nhu a
bg Igc cira so trugt khi cira so Ige rgng.
Kc^t qua dfmg mo phong time nghiem 2, trong truang hgp triet nhieu 50 Hz co
bien do Ian hon nhieu bien do lin hieu la cac song viiong ma boa thong tin tan so thap, du-(rc chi ra iren Llinh 25.
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H i n h 25. Song v u o n g hi c h i m t r o n g can nhicu 50 Hz (a), T i n hieu d u o c loc q u a bo loc (b).
Trong thuc nghiem na\'. tan so lay mau tin hieu duge lay la 1 kFIz eho mot hieu qua \'ai toe do hoi lu eo 500 Ian lap lai. So sanh ph5 ciia tin hieu vao (Hinh 26a) va cua tin hieu ra (Ilinli 26b) eho thay thanh phAn can nhieu 50 FIz da duge suy giam di t a i 4 0 d B . a .- \ . \ V b I \\ r--N-*,v-„ •..•.• i w . u i -^i
Ket qua dong mo phong thuc nghiem J, trong truang hgp ap dung bg Ige eho he
do khoang each den vat bang cam bien sieu am, duge chi ra tren hinh 27. Chiim xung s6ng sieu am hep phan xa tir vat va klioang thai gian phat bien no so voi thai diem phat song so cap la cac yeu cau ciia he do. Llinh 27a la dang eua chiim xung sieu am
saeh duge phat ra tir cam bien sieu am duge dieu che bien do xung. Song nay duge
trgn voi nguon nhieu on trang phan bo Gauss den mire no bi nhan chim ma khong the nhan ra dang eiia no neu kliong eho qua bg Ige (Hinh 27b). Flinh 27e la ket qua tin hieu duge Ige qua bg Igc DLMS-TF eho thay hieu qua ro ret eiia viee nang ty so tin hieu tren ean nhieu (SNR) eiia bg Ige.
Ket qua nay eung eho thay be se hoi tu sau ehiing 500 xung lay mau tan so 1 MHz, tire la sau khoang thai gian ca 0,5 msec. Trong khoang thai gian do thi chua the xac dinh ro xung phan xa duge. Vai toe do am lrong Idiong khi ca 342 m/s thi khoang each nay la:
0.5 X 10"^ X 324
khoang each cue tieu = — — — ^ = 0.081 /;/ = 81 cm