area paging systems. 2 x CHl/18C. DD 1969. WITHDRAWN.
Two Tone Amplifiers of narrow bandwidth used in MN2M/4,
MN2M/6 for signalling tones at different frequencies.
Gain: adjustable from 0 to 80dB. A = 9.6kHz, 9.8kHz;
B = 10.6kHz, 10.8kHz; C = 11.6kHz, 11.8kHz; D = l2.6kHz,
l2.8kHz; E = l4.6kHz, l4.8kHz; F = 7.6kHz, 7.8kHz;
G = 8.6kHz, 8.8kHz. CHl/18A, pegs 5, 30. DD 1969.
DD Spec 11.117(71). ACO. OBSOLESCENT.
Decibel Meter Amplifier used
setting sending levels to line.
Printed board with 15 way plug.
DDHB 2.184. OBSOLESCENT.
in PA6/60, PA6/6l, for
Updated version of AMl/2.
DD 1969. DD Spec 2.304.
Power Amplifier used in PSl/27 to deliver SOW at a
frequency between 15Hz and 100Hz when driven by OS3/5.
ISEP p.c.b. 100mm x l78mm with 25 way connector, coding
positions 3, 11, 17, mounted in metal frame. DD 1969.
DD Spec 1.74. DDHB 1.49. ACO. OBSOLESCENT.
S.i.S. Audio Expander used in association with UN3/27
which provides the control voltage for gain regulation.
Includes de-emphasis network CHl/12A, pegs 29, 35.
DD 1969. DD Spec 2.321. DDTM 2.206. ACO. OBSOLESCENT.
Relay Drive Pulse Amplifier used to amplify pulses from
UN23/7 to operate the appropriate 50V coils in the relay
UN23/5, UN23/6, UN23/7, UN23/8, UN20/l5. BBC/ISEP
connector, coding positions 9, 13, 21. DD 1969.
Relay Drive Pulse Amplifier used in EPlM/ll for local end
line switching controlled by UN23/9. Includes 3 dual
amplifiers and relays. Printed board with 33 way ISEP
plug, coding 3, 7, 15. DD 1969. CANCELLED.
Input Amplifier for
Reverberation Unit. Used
11 way ISEP plug, coding
DDTM 1.69. OBSOLESCENT.
driving Hammond 4F Spring
with AMl/42 in UN4/1. PCB with
DD Spec 1.84.
Output Amplifier for Hammond Spring
Type 4F. Used with UN4/l. PCB with
11 way ISEP plug,
1.85. DDTM 1.70.
Isolating Amplifier first used in PA8/308 to isolate
programme feeds from ring mains in cue programme sending
applications. Impedances:- source 75~ or lower, input
5k~, output 330~, load 5k~ or higher. PCB. DD 1971.
DD Spec 3.535. ACO. OBSOLESCENT.
Processing Amplifier, used in RD4/8
AMl/44. BBC/ISEP printed circuit
connector, indexing positions 3,
in conjunction with
board with 25 way
17, 19. DD 1971.