FL3/l8
FL3/l9
FL3/20
FL3/2l
FL3/22
FL3/502
FL3/504
FL3/505
FL3/507
FL3/508-527
FL4/l
FL4/2
.. 135 -
FL3
Highpass Filter, lO.7MHz used in RC3M/4, 6 to increase
image frequency re:iection of AM2l/l in region of 8. 7MHz.
DD 1967. DD Spec :i .131. OBSOLESCENT.
Highpass
DD 1969.
Fil ter, 9. 6kHz
DD Spec~.304.
used in OTl/3. Printed board.
DDHB 2.184. OBSOLESCENT.
Highpass Filter 6.~kHz used in OTl/3. Printed circuit
board,
DD 196'~.
DD Spec 2.304.
DDHB 2.184.
OBSOLESCENT.
Highpass Filter, 2kHz used in EPlM/12 to separate the
switching tones fr)m telephone speech on the control line
BH-WRT. Complemen~ary to FL4/45. CHl/18C, pegs 36, 39.
DD 1969. CANCELLED.
Highpass Filter, 5kHz used in EPlM/12 to separate
switching tones fr)m possible programme material over the
BP link to WTR in the event of failure of cables between
BH and WTR. CHl/l8C, pegs 36, 40. DD 1969. CANCELLED.
Filter, Highpass, 50c/s, for reduction of 50c/s or lOOc/s
hum present when using sine-squared pulse and bar signal
for adjusting equalisers. 356mm x l27mm x l14mm.
Originally coded FI3/502. DD 1957/62. DD Spec 6.70.
OBSOLESCENT.
Basic Highpass Filter used in Band I receiving circuits.
Comprises box with printed cards less components. Serial
numbers indicate ~articular arrangement of components and
cut-off
frequEncy.
DD 1957/62.
DD Spec 5.62.
OBSOLESCENT.
Switchable Highpaes Filter used with telecine equipment to
reduce 1.f. hum etc. Cut-off frequencies: 56c/s, 66c/s,
110c/s,
l32c/s.
Balanced 600~ circuits.
483mm x
133mm
panel mounted ir. CS2/2B for portable use. DD 1957/62.
DD Spec 2.194. O1S0LESCENT.
Highpass Filter used in MDl/503B to pass sound carrier and
reject vision carder and 6MHz. Printed board l4mm x 4lmm
x 64mm. DD 1964. DD Spec 4.46. ACO. OBSOLETE.
Band I Highpass Filters used in translator equipment.
DD 1965. CANCELLJ:D.
FL4 LmrpASS FILTERS
Used on OB Translntter Aerial to pass 50Mc/s and reject
200Mc/s. DD 1957q OBSOLESCENT.
Aerial Filter 9:~. 3Mc/ s, to
OBSOLESCENT.
p ass
Band
II .
DD 1957.

35