Thales 421, Эксплуатация и обслуживание, Страница: 128 / 256

LLZ 421
Alignment Procedure LLZ−2F (Dip./Refl.) Operation and Maintenance
ILS 420
5−14
Ed. 07.08 SOAC
5.4.1 Adjustment Procedure of Aerial Channels
See Fig. 5−2, 5−3.
NOTE: The signal path used within the SOAC is set to 9−10 on J19 of SOAC. Use the amplifiers
(+15 dB) in the signal input path only if absolutely necessary.
5.4.1.1 CRS Posn. Channel
(Input connector J9)
− Connect oscilloscope to TP51 and TP59 (GND). Measure output level.
Adjust IF gain to achieve approx. 3.6 Vpp output: perform first coarse alignment removing or insert-
ing attenuators with JP16,17 or JP18,19; perform fine adjustment with R90 and finally R377.
5.4.1.2 CRS Width Channel
(Input connector J7)
− Connect oscilloscope to TP53 and TP59 (GND). Measure output level.
Adjust IF gain to achieve approx. 3.6 Vpp output: perform first coarse alignment removing or insert-
ing attenuators with JP7,8 or JP9,10; perform fine adjustment with R43 and finally R382. R383 is
set to maximum. Phase adjustment is not needed. R166 remains in mid position.
5.4.1.3 CLR Width (1) Channel
(Input connector J18)
− Connect oscilloscope to TP39 and TP59 (GND). Measure output level.
Adjust IF gain to achieve approx. 3.6 Vpp output: perform first coarse alignment removing or insert-
ing attenuators with JP37,38 or JP39,40; perform fine adjustment with R286 and finally R343.
Phase adjustment with R353 is factory set and not needed. R345 remains in mid position.
5.4.1.4 NFM Channel
(Input connector J10). Refer also to 5.4.3.4.
− Connect oscilloscope to TP41 and TP59 (GND). Measure output level.
Adjust IF gain to achieve approx. 3.6 Vpp output: perform first coarse alignment removing or insert-
ing attenuators with JP22 or JP23,24; perform fine adjustment with R105.
IF gain set
R286
CLR Width in
J18
TP31
out
CLR Width
TP71
R343
JP37
JP39,40
in
TP27
TP39
TP25
input attenuation
−5 dB
Output level adjust
−10 dB −10 dB
Phase adjust (not used)
3.6 Vpp
R345
R353
JP38
TP26
set to mid position* setting depends on local conditions set to mid position: 3.7k
factory
+15 dB
ca. 0.7Vpp
IF gain set
R90
CRS Posn.
J9
R377
TP62
out
CRS Posn.
TP16
JP16
JP18,19
in
TP61
TP51
input attenuation*
−5 dB
Output level
−10 dB −10 dB
3.6 Vpp
JP17
set to mid position* set ting depends on local conditions
+15 dB
ca. 1Vpp
IF gain set
R43
CRS Width In
J7
R382
TP64
out
CRS Width
TP8
R383
JP7
JP9,10
in
TP13
TP53
TP10
input attenuation
−5 dB
Output level adjust
−10 dB −10 dB
Phase adjust (not used)
3.6 Vpp
fixed
phase
TP66
R166
JP8
TP11
set to max. set to mid position* set to mid position: 3.7k setting depends on local conditions
+15 dB
ca. 1.8Vpp
IF gain set
R105
NFM Posn.
J10
out
NFM Posn.
TP18
JP22
JP23,24
in
TP41
input attenuation
−5 dB
Output level
−10 dB
3.6 Vpp
set ting depends on local conditions
* initial setting
TP59, TP30 GND
+15 dB
ca. 0.6Vpp
Fig. 5−3 Adjustment of detector channels for aerial monitoring