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From time to time, ghosts come back to haunt me, arising from articles I have written in the past. For example, the Editor recently forwarded to me an interesting query about “The MOS controlled thyristor”, an article which appeared in these pages in the September 1993 issue. Other such ghosts have surfaced from even further back; my first contribution to these pages - a Design Idea entitled “Two for the price of one” - was back in about 1970, a useful circuit although I no longer have a copy of it as published. It’s not just from articles either. Occasional queries arrive, triggered by people reading my books, particularly the one titled “Oscilloscopes”†. This was first published in 1981, is now in its fifth edition, and has never been out of print.
These “ghosts” are always interesting, and originate from readers just about anywhere, France, India, Australia, the USA among other places, all come to mind. They often set me thinking even further back over a career in electronics spanning half a century, to days - for example - spent servicing AI10 units. Airborne Interceptor Mk10 was an airborne radar which saw service during the Second World War, still in service with the RAF’s Gloster Meteor NF11 night fighters in the mid fifties, although by then hopelessly out of date. The American “doorknob pentodes” in the IF strip were unobtainable by then, explaining the pilots’ routine complaints of low sensitivity.
A couple of years later found me at The Central Research Laboratories of The G.E.C., in the days when that company’s motto was “Everything Electrical”. The labs were much later renamed “The Hirst Research Centre”, and have now disappeared off the face of the earth, to be replaced by houses, shops and what-have-you. It was, in its heyday, an extraordinary institution, where Ph.D.s were two a penny, and a carefree university-student atmosphere pervaded the buildings. There, at one stage, I had access to a diffusion furnace, and stayed behind one evening to make myself a silicon rectifier. This was for a mains power supply for my home-made battery portable radio, using DK96 series valves with their 25mA filaments. They were happy days, when petrol cost four shillings (20p) a gallon, and - following WWII - things could only get better. Some of the extraordinary activities and characters at the CRL of the GEC in those days would doubtless be of interest to, and probably even strain the credulity of, a later generation, but space dictates that any such reminiscences must await another occasion.
† ISBN 0 7506 4757 4 Newnes/Butterworth-Heinemann Ian Hickman
Published in the April 2004 issue of
Electronics World, this leader prompted the following letter from a reader in
Bristol, published the following month.
knows your whereabouts?
Edinburgh, you can buy time on a parking meter with your mobile phone. You call the number displayed on the meter (with caller I.D.
enabled), and a voice response system asks for the meter’s I.D. number. This
enables the parking system server to identify your location and activate the
meter. The latter now lets you choose how long you want to pay for and prints
out a ticket for you to place on view in your car. It also instructs the server
to charge that amount to your credit card, or to a special account.
Obviously, in the process, the system knows just where you are.
But this is not the only, or even the earliest system for locating you. Someone calling the U.K. emergency number 999 from a fixed
line may be unable, or not in a fit state, to give his or her exact location.
But the origin of the call can be traced via the exchange(s) involved,
and the person thus located. In the United States, E911 (the “Enhanced 911
mandate”, passed 1996, revised 1999) requires all cell-phone operators to
install facilities, able to locate a mobile caller dialling the 911 emergency
number, to within 50 to 100 “meters”, by 2005 (is the U.S. going metric at
In Europe, wireless network operators are already required by E112 to be
able to locate a caller making a call to the emergency number 112.
However, there is currently no accuracy specification, and most wireless
network operators will simply return the location of the cell via which the call
was set up - leaving a “fix” which could cover hundreds or even thousands of
metres. The GSM system is now
spreading in the U.S., and mobile network operators there use uplink time
difference of arrival. This depends
upon the mobile being received via at least three base-stations, and the system
may presumably have to instruct the mobile temporarily to transmit at higher
power, to reach enough base-stations. The
dominant U.S. mobile technology, like GSM, also uses TDMA, and uplink time
difference of arrival technology is appropriate there also.
CDMA (code division multiple access) is a different problem as uplink
time difference of arrival is not appropriate, and many CDMA mobiles have a GPS
function built in. This returns good position information if the user is
outdoors, but less accurate if indoors or in a heavily built up area.
These systems are designed to identify a caller’s location in an
emergency, but in principle could be used by the police continuously to track
any suspect, or by national security services for the same purpose, building up
a record of an individual’s movements up to the present time.
There are also other ways in which one’s location, either current or at
some time in the past, could be determined.
RFID (radio frequency identification) tags are set to become ubiquitous.
The Gillette Company of Boston,
USA, proposes to buy up to five hundred million or so tags, to mark its razors
and packs of blades. These tags are
already incorporated in product being sold there, in U.K. and Germany, and the
resulting improved inventory management is expected to save billions annually.
The tags, read by scanners, will provide records giving details of the
time of the sale and outlet, but will remain in the product and be accessible in
principle thereafter. Similar tags
could appear hidden in the hem of clothes, the binding of books, car tyres and
almost any merchandise you can think of. The
tags cost tens of pennies today, this will be just a few pence each before long.
Almost any purchased item will be able to identify the whereabouts of the
purchaser either in the past or in some cases, currently, creating - or breaking
- an alibi. Even the humble credit
card will leave a trace whenever used, creating a record of what and when you
bought what where. Japan is well
ahead of the game, and before long there you will be able to opt for
personalised targetted advertising. Knowing
where you are, the system could ring your mobile to alert you that the shop you
are approaching sells your favourite brand of chewing gum.
Some of these means of telling where you are, are obviously beneficial,
even potentially life-saving. But
others can be expected to raise anxious representations from civil liberty
groups. For more details on this
story, see the July 2003 issue of “Spectrum”, the journal of the IEEE.
Published in the September 2003 issue of Electronics World
is surely a technology that is about to explode and proliferate into every
sphere of modern life. I have been
keeping a weather eye on this topic for about fifteen years, since involved,
while with Plessey/Siemens, in a study into the feasibility of using Radio
Frequency IDentification tags to keep track of children in theme parks.
A practical problem - several get lost every day and one or two a year
get lost permanently - it is a difficult application for the technology,
due to the range required. In
retailing, a tag is only required to operate over a short range, a few metres at
One of the problems holding back widescale application of RFID tags has
been that of standardisation. It
would be a great disadvantage if Europe, the US and Asia went their different
ways, with mutually incompatible systems. Fortunately
international co-operation is on its way, driven by the needs of industry and
commerce. For keeping track of
pallets for the transfer of goods, EPCglobal Inc. is developing the proposed the
EPCglobalG2 standard. This uses a
96 bit format, and tags using this format are already available, with read and
write operating ranges up to a few metres, while operation at UHF permits
multiple tags to be read/written per second without collisions.
I don’t have details to hand of the allocation of the 96 bits to
headers, serial numbers etc. but 2^96 is a seriously large number, about
28! Major concerns, both commercial
and governmental, are mandating the use of RFID technology, with Walmart, Tesco,
US D.O.D and others requiring its use in their supply chain and logistics
systems as early as 2005. And in
the EU, new regulations will require the use of tags to keep track of individual
animals such as beef herds etc. with the system already proven by pilot trial
schemes. Tags complying with ISO 11784/85 were placed subcutaneously in each
animal, allowing it to be tracked at various points during its lifetime, and
after. Knowing where the beef the housewife buys comes from, should boost her
confidence - and sales - in the view of past catastrophes such as scrapie, BSE,
foot and mouth disease, etc.
Another burgeoning RFID application is smart tickets, which can be loaded
with credit like a phone card, and debited automatically, in accordance with the
journeys undertaken by the holder. Card
readers on the various forms of transport could simplify matters by enabling a
traveller to make a journey involving both buses and trains, without the need
for a through-ticket or separate tickets for each stage.
Already trialled in Perth, Australia, it is shortly to be tried out on
the Seattle mass transit system.
Other applications abound, and Jo(e) Public will have to get used to tags
appearing everywhere, whether he or she likes it or not.
For instance, tags in clothes may cause the washing machine to inform you
of the right programme to use for each, while tags on food packs may enable the
smart fridge to warn you when you are running low on butter, or eggs, or milk -
- -. In time it will become as difficult to buy a “dumb”
fridge or washing machine as it is now, for those with a “keep it simple -
less to go wrong” philosophy, to buy a car without central locking.
Much more on RFID tag technology and applications can be found in the
Philips publication “ON THE MOVE, Identification News”, Volume 6 Issue 3,
September2004. Philips’ World
News, Volume 13 Number 3, September 2004 also covers the topic, with other
useful and interesting articles such as Bluetooth/WLAN, intercommunication,
hands-free car phones, class D amplifiers and electronic ink, among others.
Published in the November 2004 issue of Electronics World
I was an undergraduate, in the late 50s and early 60s, all engineering students
(with the exception, if I remember rightly, of the aeronauticals and the
chemicals) took the same course in the first year. So we all studied
thermodynamics, strength of materials, dynamics of fluids, theory of structures
and metallurgy, as well as electrical engineering. This broad syllabus was both
interesting and stimulating, and some has stuck permanently. If ever I had to
calculate the flow versus height over a given Vee-notch weir (can't remember off
hand whether I need Francis' formula or d' Arcy's formula), I could still do so
as the appropriate textbook is residing awaiting (improbable) use, in the
technical section of my library. In the later years of the course, the content
of the maths curriculum was identical to that of the Honours Maths syllabus,
except that we made do with “it can
be shown that...” rather than proving all those results in full mathematical
The situation is very different nowadays, since the frontiers of
knowledge have expanded so enormously. Such a broadly based foundation is
considered an unaffordable luxury. It is now thought that, to be useful to an
employer and hence secure a job, a new graduate must specialise - not in
electrical, or some other branch, of engineering. Not even in light versus heavy
electrical engineering, but in a smaller field still - telecommunications for
example. Presumably the heavy electricals have also partitioned themselves into
ever smaller specialisms, while various universities, some redbrick, some even
newer, offer specialised degrees in a variety of arcane subjects, from the
infamous 'media studies' to others as bizarre as African tribal art.
So does the newly qualified telecomms (or whatever) engineer emerge with
exactly the right toolkit of knowledge to fit into a research or development job
like a round peg in a round hole? The answer of course is no. The syllabus is
never really up to date: when I graduated in 1961, there were plenty of valves
in the syllabus, but no semiconductors. I gather that syllabuses are not quite as far behind the times as that nowadays, but the technology moves on
remorselessly and the new graduate, assuming he is lucky enough to find an
employer, is likely to find himself faced with a fairly steep learning curve,
despite the best efforts of universities. The inadequacies of the syllabuses are
generally recognised, even by politicians, so they must be glaring indeed! For
example, the UK government (or, to be more specific, the Department of Trade and
Industry) sponsored over the last few years, the Radio Frequency Engineering
Education Initiative, in an attempt to alleviate the dearth of competent RF
engineers face by an industry busy with Bluetooth, IEEE S02.11a, b, c, and g,
HomeRF, WLANs of all sorts, etc. Having been involved with the implementation of
the Initiative at my nearest University, I
know from first hand that current electronics courses are completely deficient
in practical hands on work with real live components and circuitry - it is so
much easier to sit a student down in front of a PC and tell him to work through
the exercises with SPICE.
surprising, then, that employers are always looking for engineers already
experienced in whatever happens to be their particular line of product
development. Some firms, only the largest and then not always, are willing to
take on the raw new graduate, and let him build up his experience base to the
point where he is positively contributing to the firm's advancement. But a
glance at the recruitment ads in the 'freebies' (controlled circulation
magazines) shows that most firms seek to obtain their experience staff by
recruiting from other firms, who then, naturally, feel forced to poach engineers
in their turn.
problem is, of course, the low esteem in which engineers are held; not by the
general public - who cares about that - but by employers. And let's be honest,
esteem is a quality that can be accurately measured - in pounds sterling.
Published in the January 2003 issue of Electronics World
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