AT3/502A
AT3/503
,\T3/504
AT3/S05
AT3M/506
AT3/S07A
AT3/507B
AT 508
AT3/511A
45 -
AT3
UN1/536. CH1/l2A.
WITHDRAWN .
DD 1963. DD Spec 7.13.
DDHB 7.66.
Similar to AT3/502 but also includes PS2/22D which is used
with external equipment when the fader is incorporated in
an AGC system. Replaced by AT3M/506. DD 1963.
DD Spec 7.13. DDHB 7.66. OBSOLESCENT.
Used in AT3/S02 and AT3/S02A. Indudes UN1/28. Replaced
by AT3/505. DD 1963. WITHDRAWN.
Comprises 3 separate 75~ splitting networks
outputs and attenuation of 12dB. Box l14mm
Used
on
EPS/502.
DD 1963.
DD Spec
OBSOLESCENT.
each giving 2
x 64mm x 38mm.
8.173. ACO.
Continuously Variable Attenuator used in AT3M/S06.
Provides attenuation of infinity to 9dB controlled by
applied d.c. voltage of 0 to l2V. Replaces AT3/S03.
DD 1965. DD Spec 7.128. ACO. OBSOLESCENT.
Continuously Variable Video Attenuator used in Line Store
Standards Converters. Replaces AT3/502A. Comprises
AT3/505 and PS2/22D in CH1/12A, pegs 3, 2S. DD 1965.
DD Spec 7.126. ACO. OBSOLESCENT.
Video Frequency Attenuator used in APlM/547 for 60 to 50
field conversions. Contains loss and mixing networks and
ON/OFF switch for vertical aperture correction. CHl/12A.
DD 1968. WITHDRAWN.
As AT3/507A but for 50 to 60 field conversions. Contains
loss and mixing networks only. DD 1968. WITHDRAWN.
Video Frequency Attenuator used in PAlM/547 to replace
UNl/597 when converting 525/60 to 625/60 in C06M/504.
CHl!12A, pegs 20, 32 as for UNl/597. DD 1968. WITHDRAWN.
Video Frequency Switched Attenuator used in conjunction
with UN9/5S0 and 15dB Amplifiers to adjust the net gain to
zero when a change of standards conversion requires
different equalisers. CHl/12A. DD 1968. WITHDRAWN.
6dB Video Frequency Attenuator used at the mixed input
terminal of PA18/S19. Unsymmetrical 7S~ input impedance.
Screening box and P.O. No. 1 plug. Other attenuation
values possible, distinguished by suffix letters.
DD 1971. OBSOLESCENT.
AT4 RADIO FREQUENCY ATTENUATORS
IF Attenuator used to reduce the output level of MD1/503A
for driving EP7/507. The vision attenuator includes notch
filters to assist in vestigal sideband shaping. CHl/12A,

45