Page 143 - 30105-2003 การวิเคราะห์วงจรอิเล็กทรอนิกส์ความถี่สูง

135

3.

ก !ก (3.10) Z P = Z S % Z = Z N 2 P
S
P
N 2 N 2 N 2
P S S
, Z = R L (ab) , Z = R L , N = N 12 , N = N 32 ;
S
S
P
P
2
R N 12
L

$
R = (3.16)
L (ab) 2
N 32

"#
3.10 ก + 3.14 + %! 9 C ( ) , R ( ) , F ) % F )
CT ab L ab R L R L
( 12
( 21
×
10
C CT N 2 22 20 10 − 12 ( ) 2 80 pF
- ,
ก !ก (3.15) C CT (ab) = 2 = 2 =
N 12 ( ) 5
R N 2 12 75 ( ) 5 2
L
ก !ก (3.16) R L (ab) = = = 1,875 Ω
N 2 ( ) 1 2
32
g m ;
ก !ก (1.16) C b c ′ = C ob , C b e ′ = − C ob
π
2 F
T
, C b c ′ = 0.5 pF
×
195.019 10 − 3 − 12
×
C b e ′ = 9 − 0.5 10 = 4.675 pF
×
×
×
2 3.14 6 10
1
ก !ก (3.13) F =
( R L 21 )
2π L (C + C )
21 BT b e ′
1
F R (L 21 ) =
(2 3.14× ) { 1 10 − 6 ( 25 10 − 12 + 4.675 10 − 12 )}
×
×
×
F = 29.231 MHz
R (L 21 )
1 1
ก !ก (3.14) F = =
( R L 12 ) 2π L C (ab) (2 3.14× ) ( 375 10 − 9 × 80 10 − 12 )
×
×
12 CT
F ( R L 12 ) = 29.072 MHz
Ω
Ω Ω Ω
" C CT (ab) = = = = 80 pF, R L (ab) = = = = 1,875 , F R (L 21 ) = = = = 29.231 MHz, F R (L 12 ) = = = = 29.072 MHz;

ก 9 F % F ! 9 "ก 29 MHz "
E ก
2
( R L 21 ) ( R L 12 ) g

$ ก9
9 "
,

R
L
3.5.2.5 ก
$

'
B (L )
W 21
B 9
' ( ' &
9 L , & 9 (C C ), R
W (L 21 ) 21 BT b e ′ gs
% r , 8 9 r ! 9 & "ก 0 Ω %& R
&9 L ก +;
R
b e ′
bb′
21
g
gs
2
R N 21
g
R gs = 2
N
11
ก

ก
ก