1. Lp2 r2 ,
Lp1 r1 .
Lp2=Lp1 - 20lg r2 /r1
2. Lp2 r2 ,
Lk// Pel ( ) (.1)
Lp2=Lk - 20lg r2+10lgPel
:
Lk =94//, Pel=200.
r2=30,20,10 5.
Lp2(5)=94-200.69+102.3=103
Lp2(10)=94-201 +102.3=97
Lp2(20)=94-201.3+102.3=91
Lp2(30)=94-201.5+102.3=87
3. Lp2 r2 ,
Lk Pel ( ) L(θ) Dr2
Lp2=Lk - 20lg r2+10lgPel +20 lgL(θ)-Dr2
(.2-)
L(θ) Dr2 f .
:
L(θ)=(θ0)/(00)
: Lk =94//, Pel=200.
r2=30,20,10 5.
θ=0,20,40,60 (L(θ)=1,0.6;0.3;0.1)
Lp2=?
Lp2=Lk - 20lg r2+10lgPel +20 lgL(θ)
Lp2(30)=94-20lg30+10lg200+20lg1=94-29.54+23+0=87.46
Lp2(20)= 94-20lg20+10lg200+20lg0.6=94-26+23-4.4=86.6
Lp2(10)= 94-20lg10+10lg200+20lg0.3=94-20+23-10.45=86.55
Lp2(5)= 94-20lg5+10lg200+20lg0.1=94-14+23-20=83
, -
( )
L=17dB+Lk+10lg Pel-10lg(A)-
= - , ( , , ).(f)- .
= - ( = )
=αS= , αi- ,An- ,m-
, 100003, 1, =0.161V/T=16102
==10lgγL - , γL- , ( ).
|
|
γL =Pa/Pa=p2(00)/2, Pa- , Pa- .
γL , , ( ) , 0. , , . γL .
(.)
:
1. , 1000, -=9, Lk=104//, 250.
100003 =1.
L=17+104+10lg250-10lg1610-C=121+24-32-9=104
2. 100, 94//, 2000 -12) 5003, 2.
2.1. = 0.161V/T=402
2.2 10lg Pel = L -17dB -Lk +10lg(A)+=100-17-94+10lg40 +12=1+16=17
lg Pel=1.7, Pel=10 1.7=50,1