D38999/20JJ11SB-LC Amphenol, D38999/20JJ11SB-LC Datasheet - Page 132

• Manufacturer Part Number: D38999/20JJ11SB-LC
• Description: Circular MIL / Spec Connectors 11P SIZE 25 WALL MOUNT RECEPTACLE SKT
• Manufacturer: Amphenol
• Series: 38999 Seriesr

Specifications of D38999/20JJ11SB-LC

• Mil Type: MIL-DTL-38999 III
• Product Type: Connectors
• Contact Style: Socket (Female)
• Shell Style: Receptacle
• Shell Size: 25
• Number Of Contacts: 11
• Insert Arrangement: 25-11
• Mating Style: Threaded
• Mounting Style: Panel

Impedance Matching Formula
(your system to a 50 ohm system)
The following formula and example are offered in order to
deter mine the expected filter performance in an impedance
system other than 50 ohms.
With the attenuation expressed in 50 ohms and the transfer
impedance curve shown in Figure 1 below, a designer can relate
the expressed attenuation to the input and output imped ance of
his circuit.
Example:
Formula (Taken from Figure 1):
(1)
(2)
(3)
1.4 x 10
for 65 dB in a 50 ohm system
140
120
100
80
60
40
20
10
0
Noise is 40dB above specification level at 100 MHz
Input and output impedance are 10 and 100 ohms
respectively
Amphenol
attenuation at 100 MHz and +25°C
-4
-2
= transfer impedance
®
VHF 7000 pf filter has a 65 dB minimum
10
Attenuation vs Transfer Impedance in 50 Ohm System
Contact Amphenol Aerospace for more information 800-678-0141 • www.amphenol-aerospace.com
-3
Transfer Impedance - Z
10
-2
Figure 1
Atten (dB) = 20 log
Atten = filter performance in a system other than 50 ohms
Atten (dB) = 20 log
Attenuation = 56.3dB
In this case, the 7000 pf VHF filter will give 56.3 dB which is
16.3dB below the desired reduction in noise (40dB) as stated
in the above problem.
Z
Z
Z
S
L
12
= load impedance
10
= source impedance
= transfer impedance
12
-1
Ohms
10
10
1 +
1 +
10
Amphenol
1.4 x 10
Z
-0
12
(Z
Z
S
S
Z
10(100)
+ Z
L
–2
(10 + 100)
L
)
Aerospace
10
1
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