received signalling sould consist of a tone pair sp aced
200Hz apart in the band 6-l4kHz. For example, the tone
pair could be 6.6kHz and 6.8kHz; 7.6kHz and 7.8kHz etc., up
to l4.6kHz and l4.8kHz. The upper received tone would have
been modulated by differential phase shift keying (dpsk).
The 'lower' received tone e.g. 7.6kHz would be used for
securi ty. The local oscillators and programme bandwidth
can be altered by changing two filters, FL4/6SA-L contained
in the DM3/S and FL2/21A-L contain ed in the DM3/6. Power
requirements 2l0-260V a.c. at l2W. 2U 482mm BMM sub rack.
Sub units PS2/194A, DM3/S + FL4.6SA-L and DM3/6 +
FL2/21A-L. DD 1979.
Audio Line Signalling Equipment, Receive. This equipment
is used to decode two separate pairs of signalling
information that have been transmitted above two sound
programme circuits. The received signalling should consist
of two tone pairs spaced 200Hz apart in the band 6-l6kHz.
For example, the tone pairs could be 6. 6kHz a nd 6. 8kHz;
7.6kHz and 7.8kHz etc., up to l6.6kHz and l6.8kHz. The
equipment can be altered to accept different tones by
changing local oscillators and programme filters (FL4/6SA-
L) contained in the separate DM3/S' s. Power requirements
2l0-260VA at l2W. 2U BMM sub rack. Sub units PS2/194A,
DM3/S + FL4/6SA-L. DD 1979.
Sound Multiplex Transceiver. This equipment will
simultaneously multiplex and demultiplex a number of
control/telephony channels and narrow-band music channels
over an audio bearer of lS kHz bandwidth. The telephony
channels may be used in a 4-wire or a 2-wire mode. In the
2-wire Linesman mode and push button MF telephones may be
used directly without additional units. This design is
intended to replace the obsolescent EP2M/3 (Receiver) and
EP2M/4 (transmitter). Power requirements 240V ac (100 VA)
or 20-4SV dc (lOOW). 4U rack mounting C/N case.
Supersedes EP2M/3 and EP2M/4. DD 1984.
OB Vision Carrier Equipment. This equipment receives a
combined baseband and carrier signal. Both channels having
video bandwidths, the baseband being d.c. to S.SMHz; the
carrier channel being 8.SMHz to lS.SMHz for vestigial side-
band operation. The cable equalisation for a maximum 7.SKm
with 9. Smm coaxial cable is equalised in the EP2M/ S03.
Power requirements 220Vac to 260Vac at .. 200mA. 7" Imhof-
Bedco CDX. Sub-units FL1/S20A, EQ13/S03, EQ4/S0S, FL1/S21,
DM2/S10, EQS/S29, PS2/131, EP2M/S03, IN6/S07. DD 1982.
Vision Carrier Equaliser Equipment. This equipment is used
in conjunction with the EP2M/S02, Vision Carrier Equipment.
It equalises the vision carrier signal that is in the band
8. SMHz to lS. SMHz when used on coaxial cables of defined
characteristics. This unit is the EQ4/S08. It also houses
a PA20/S2S this being a termination panel for the incoming
cables. Power requirements +12V at SOmA, -12V at SOmA. 2U
BMM Frame, PN3/SS. Sub-units EQ4/S08, PA20/S2S. DD 1981.
Digital Video Multiplexer. This unit produces a
multiplexer digital video output signal which conforms to