e997017.pdf
(
21 KB
)
Pobierz
138908379 UNPDF
impedance matching network
017
cable with an impedance
Z
2
, reflections ensue that cause standing
waves. Reflected signals then collide with incoming signals. The
consequent superimposition of the two signals causes the result-
ing signal to be weak at certain points in the cable or network and
very strong at others.
The matching network shown in the diagram matches two
unequal impedances, provided that
Z
1
is greater than
Z
2
. The table
shows a number of frequently encountered values of
Z
1
and
Z
2
and the requisite resistors, as well as the resulting attenuation. The
resistor values are the nearest standard values in the E-96 series
to the computed ones.
The matching of impedances in this manner is wideband and
is often used in the test and measurement operations when 75 Ω
ad 50
R1
Z
1
Z
2
R2
Z
1
>
Z
2
994028 - 11
Z1
Z2
R1
R2
Attenuation
appliances are used.
The resistor values are calculated from
75
Ω
50
Ω
43
Ω
2
82
Ω
5
5,7 dB
150
50
121
61
9
9,9 dB
300
50
274
51
1
13,4 dB
R
1
=
Z
1
–Z
2
R
2
/(
Z
2
+R
2
)
150
Ω
75
Ω
110
Ω
110
Ω
7,6 dB
300
75
243
82
5
11,4 dB
R
2
=
Z
2
√
Z
1
/(
Z
1
–
Z
2
)
G. Kleine
When r.f. signals are transferred directly from a cable or other out-
put terminal with an impedance
Z
1
to a signal input terminal or
where
Z
1
and
Z
2
are as described earlier and their, and the resis-
tor, values are in ohms.
[994028]
Plik z chomika:
TirNaNog
Inne pliki z tego folderu:
bge.jpg
(22 KB)
detail1.htm
(5 KB)
detail10.htm
(6 KB)
detail12.htm
(12 KB)
e991018.pdf
(794 KB)
Inne foldery tego chomika:
1974
1975
1976
1977
1978
Zgłoś jeśli
naruszono regulamin