FL4/52l
FL4/522
FL4/522A
FL4/523
FL4/544
FL4/547
FL4/548
FL4/549
FL4/550
FL4/551
FL4/553
FL4/555
FL4/556B
FL4/556E
- 141 -
FL4
Comprises FL4/501 and FL4/508 on CH1/12C with changeover
relay. DD 1964. DD Spec 7.42. DDHB 7.78. OBSOLETE.
Filters, Lowpass, Link, 5l0MHz used for a phase
compensated bandwidth restriction of 5.0MHz. Copper box
184mm
x
70mm
x
102mm.
DD 1964.
DD Spec 9.39.
OBSOLESCENT.
5.0Mc/s Link Filter in CHl/12B, otherwise as FL4/522.
First used PAl/5l6. WITHDRAWN.
Band I
DD 1965.
Lowpass Filters
OBSOLESCENT.
used in
translator equipment.
RGB Luminance Filter to match random noise bandwidth of
each colouring channel and the luminance channel of a 4
tube colour camera to the nominal bandwidth to improve
signal/noise ratio. CHl/26B. DD 1965. CANCELLED.
Lowpass Filter (fc = 58Mc/s) to pass Channel
sound and vision and reject 72Mc/s, 85Mc/s,
450Mc/s. Used as serial filters in
centimetric fixed links at Great Orme's Head.
WITHDRAWN.
1, Band I
l70Mc/s and
RC4/50l for
DD 1965/66.
Lowpass Filter, 63.5Mc/s to pass Channel 3 and reject
74.75Mc/s and 79Mc/s. Used at Sandale in connection with
Sandale-Lowther Hill radio links. Printed board in copper
box. DD 1965/66. WITHDRAWN.
Lowpass Filter, 5Mc/s, giving a bandwidth restriction of
5Mc/s with a fairly sharp cut off. Printed board in
Eddystone box. DD 1965/66. WITHDRAWN.
Lowpass Filter, Linear Phase, 3.6MHz.
Printed circuit board in small metal
DD Spec 9.62. OBSOLESCENT.
(405
box.
lines).
DD 1966.
Lowpass Filter, Linear Phase, 5Mc/s. Similar to FL4/550
but for 525 lines. DD 1975. WITHDRAWN.
Lowpass Filter used on translators to pass Bands I and 11
and stop Band Ill. 203mm x 83mm x 83mm. DD 1966.
DD Spec 12.26. OBSOLESCENT.
Luminance Lowpass Filter used to separate the luminance
information from the signal provided by GE2M/543 so that
the chrominance to luminance crosstalk amplitude can be
measured. Incorporates a 50Hz rejection section. Printed
board in box with PO plugs. DD 1967. WITHDRAWN.
Lowpass Phase Corrected Filter, 4l5MHz, 75~, used for
improved band limitation in 525 line systems. Printed
board. DD 1967. DD Spec 9.89. WITHDRAWN.
Lowpass Phase Corrected
comb line filter and
C06/504. Printed board.
Filter,
vertical
DD 1968.
2MHz, 75~, used in the
aperture corrector in
WITHDRANW.

41