L TIl£P CAN KHAI mA DU IEU DO) VOI BAI TOAN PHAN :n
1520 25 tan so (Hz)
tan so (Hz)
Hinh 5. Phan tich mat do pho cong suat (cam bien AZ)
De viec dinh gii de dang hon thi chiing ta sir dung ky thuat lay trung binh de thu dugc mat do phd cdng suat min han (xem hinh 6). Rat de nhan thay phd tin hieu nam trong dai tan tir 0.3 Hz tdi 32 Hz la khi deu, cd the dugc coi la nhieu nen. Tuy nhien, sai Idi tram trgng dugc nhan thay d dai tan sd dudi 0.3 Hz. Day chinh la nhieu rung (tan sd bien đi chim) gay nen do trdi tram trgng dac trung ciia cic cam bien che tao bdi cdng nghe vi co dien tiị Loi ve do trdi nay thudng dugc xir ly bang cich diing bg Igc tdi uu Kalman [4].
Hinh 6. Mat do phd cdng suit (cim bien AZ) ap dung ky thuat lay trung binh
Hinh 7 la ket qui phan tich mat do phd cdng suit cua ca 3 pha, cho phep chiing ta dua ra nhirng dinh gia quan trgng: sai khic ve phd giija pha 1 va 2 la khong dang ke ngoai trir
^eu Hoi thio ICT.rdá08 Proceedings of ICT.rdá08. Hanoi Aug. 8-9, 2008 cac dao dgng trong dai tin tii 20-25 Hz. 6
pha 3^ (xe chuyan dgng), dai tin ciia dgng hgc chuyen dgng nim trong khoang 5 - 15 Hz, li khi tach biet so vdi dai hoat dgng ciia tin hieu rung dgng eạ Chinh vi the chung ta cd tha su
dung mot Igc sd thong thip dk giam bdt tic
dgng ciia rung do xe nd maỵ
Oung yer r o may 'ne c h a j
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Hinh 7. Mat do phd cdng suit cua ca 3 pha
Cac tan sd rung cung dugc chi ra bdi cac mui ten trong anh phd cua cam bien gia tdc AX va AỴ Cac ket qua phan tich khic tren cam bien AX va AY cung dugc tien hanh theo tuin tu nhu tren.