Page 153 - 30105-2003 การวิเคราะห์วงจรอิเล็กทรอนิกส์ความถี่สูง

145

3.

"#
3.20 + %! 9 B W (L 11 ) % B W (L 12 )
β o 120
- ,
ก !ก (1.10) r b e ′ = = = 301.555 Ω
×
g m 397.937 10 − 3
2 2
r N 11 301.555 ( ) 1
b e ′
r b ep = 2 = 2 = 301.555 Ω
′
N ( ) 1
21
2 × − 12 2
C N 21 209.919 10 ( ) 1 209.919 pF
b e ′
ก !ก (3.25) C b ep = = =
′
N 2 ( ) 1 2
11
×
R r ′ 75 301.555
g b ep
ก !ก R = = = 60.061 Ω
R + r b ep (75 301.555+ )
′
g
1
ก !ก (3.27a) B =
W (L 11 ) )( − 9 − 12 )
×
×
×
×
( 2 3.14 60.061 52.6 10 + 209.919 10
B (L ) = 50.203 kHz
W 11
×
C CT N 2 22 429 10 − 12 ( ) 2 1.716 nF
10
ก !ก (3.15) C CT (ab) = 2 = 2 =
N ( ) 5
12
R N 2 12 75 ( ) 5 2
L
ก !ก (3.16) R L (ab) = 2 = 2 = 1.875 kΩ
N ( ) 1
32
1 1
ก !ก (3.18) B W (L ) = =
π
12
×
×
2 C CT (ab) L (ab) ( 2 3.14 1.716 10 − 9 × 1.875 10 3 )
×
×
R
B W (L 12 ) = 49.490 kHz
" B = = = = 50.203 kHz, B = = = = 49.490 kHz;
' ( ' + %! 50 kHz
W (L 11 ) W (L 12 )
3.6.12 ก
$

'
F R (L 11 ) F R (L 12 )
+;
9 !8 ,.

.' &
9 L % L & !

, F ( R L 11 ) % F ( R L 12 ) 11 12
C N 2 21
b e ′
ก !ก (3.25) C b ep =
′
N 2
11
2
C CT N 22
ก !ก (3.15) C CT (ab) =
N 2
12
1
ก !ก (3.13) F R (L ) =
21
2π L 21 (C BT + C b e ′ )
, F R (L 21 ) = F ( R L 11 ) , L = L 11 ( , C BT + C b e ′ ) ( C= BT + C b ep ) ;
′
21
1 (3.28)

$
F R (L 11 ) =
2π L 11 ( C BT + C b ep )
′
ก

ก
ก