Created
by Professor David Fisher from Surrey University, the APRS publishes a
series of technical monographs on key subjects that provide an invaluable
resource for all categories of the APRS membership. These are incredibly
useful documents and the association is indebted to David for the time
and devotion he has invested in them over the years.
Printed versions
are available on order from the APRS and some of the resources will be
available online in due course. We also plan to compile the monographs
into a single document that will be an essential publication for all APRS
members.
We currently
print to order and make a nominal charge for the printout time and materials:
- �5.00
for all APRS members
- �10.00
for non-members.
To find out
more call Francesca at the APRS office on 01803 868600.
ELECTRICAL
SAFETY Words: 6349 plus diagrams
In 1992, 60 people were killed by electricity. Indeed, it is possible
to sustain serious injury by contact with voltages well below the 240V
of the U.K. mains. It is the aim of this technical monograph to explain
the dangers of electricity and how they arise, and to examine some of
the legal issues involved in safety and its management. in addition, the
APRS is considering the publication of a Code of Practice for Electrical
Testing for the guidance of its studio members.
PRE-EMPHASIS
AND DE-EMPHASIS Words: 1070 plus diagrams
Pre-emphasis, followed by de-emphasis, has been used in a variety of audio
systems for many years to reduce the effects of frequency dependent noise,-
it is, therefore, a simple form of noise reduction system. FM broadcasting,
NICAM 728 and digital audio are just some of the systems that can be pre-emphasised.
THE
DECIBEL Words: 2961 plus diagrams
The decibel (dB) has a number of advantages, and some disadvantages, which
this monograph will explain. Fundamentally, the dB is a unit of gain or
loss in a system - that is, it indicates how much amplification or attenuation
a signal has undergone. in order to explain the two different uses of
the dB, it is necessary to understand its derivation.
ELECTRICAL
FUNDAMENTALS 1 Words: 2786 with diagrams
Ohm's Law allows voltages, currents and resistances or impedances to be
calculated, and is thus the most fundamental rule of electricity and electronics.
Before you can make use of it, however, you must understand the basic
concepts of electromotive force (or emf) voltage and current.
ELECTRICAL
FUNDAMENTALS - 2 Words: 4002 with diagrams
Following on from Electrical Fundamentals 1, this monograph explains
how resistances and impedances behave when connected together.
TIMECODE
Words: 5960 plus diagrams
The problem of how to lock together two or more sound or picture transports
has existed for a very long time. The film industry was forced to find
workable solutions when 'talkies' were invented...
INPUT,
OUTPUT AND CHARACTERISTIC IMPEDANCE Words: 6178 plus diagrams
The concepts of input and output impedance are important in professional
audio, because knowledge of them will help you to understand how different
pieces of equipment can be interconnected. Characteristic impedance is
a concept that will help you when interconnecting video or digital audio
equipment. it may seem unlikely that a piece of audio equipment made up
of hundreds of transistors, ICE, resistors and capacitors could ever be
represented by a circuit that was simple enough to be of any operational
use. Fortunately, this simplification is quite possible, and will allow
the most complex piece of equipment to be represented by only one or two
components. The electronic principle which allows this simplification
is known as Th�venin's Theorem.
|
