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standard for such equipment which will not be surpassed for many years.
!t has comprehensive audio input facilities for both mono and stereo
sources
and
in
addition
it
will
accept
supervisory
signals
for
monitoring purposes. Work on the development of the complete range of
equipment is expected to last for about two years and the designs will
be used in a large scale programme of installation and re-equipment.
In the television field there has been a programme of development of a
number of auxiliary units for use
with the 2 Watt transposer designed
in
1975.
These include a range of
group filters and a UHF equaliser
for offsetting fixed propagation
defects. This programme of
enlarging the range of facilities
and options available with the
transposer is expected to last for
some time yet.
In addition to this work, there has
been a programme of extensive
modifications to the existing
television UHF re-broadcast
receivers.
These were desgined some
years ago, and have been
satisfactory
in
service.
However
problems have arisen with obsolete
components and with the steady
change of operational practices and
requirements.
These latter have meant that the receiver facilities were
no longer fully adequate to meet operational requirements, and hence a
modification programme was carried out in collaboration with Transmitter
Group.
UHF Bandpass FiUer soowing
Printed FiZter EZements
The Section has also made one of its rare incursions into studio
activities, to design a new two-way system of talk-back for studio use.
The equipment is now in production, and has been well received by
operational
users.
It
is small, light, and runs for a full day on
a
simple battery. Its sound quality is such that the user does not suffer
fatigue,
a
common
problem
with
"walkie-talkie" equipment.
It
was
primarily intended for use by Floor Managers, but is likely to be used
also by Lighting Managers, Sound Supervisors and Programme Presenters
(these latter using the equipment in a one-way role).
PROJECTS COMPLETED
Television Transposers: Auxiliary Equipment
The production of 2 watt transposers has led to the development of a
number
of
auxiliary
items
such
as filters and RF
equalisers.
The
filters are used to feed transposer equipment in a multi-channel relay
station. To reduce production costs the filter elements are in printed
circuit form which minimises the test and adjustment time.
The UHF equaliser provides a means of correcting the frequency response
of a transmitting-aerial/radio path/receiving-aerial system. The
process of receiving-aerial installation and adjustment is normally one
which aims to minimise these effects, but often cannot succeed entirely
on all channels to be handled at the relay stations. If there is a
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