Radios, slipsticks, mobile devices, antennas and computers – marching to the beat from superhetrodyne to software, from sardines and porcupines to fashion shows
Once upon a time, many years ago, in the age of the vacuum tube radio receiver, stone-age cool called for blithe references to superheterodyning. You didn’t really have to know what it meant, it just sounded good – something like quoting a philosopher you never read to support a specious argument. It sounded cool. Nerd cool in those days meant you had a slide rule hanging from your belt and had a plastic protector jammed with pens of all colours in your shirt pocket. You never saw a slide rule? Well there were no computers or even electronic calculators, but a slipstick wizard could calculate all sorts of amazing things – even satellite orbits – with one of those.
Slide rules died when the Hewlett-Packard HP 35 hit the market in the early 1970s. I bought the HP as soon as soon as I could afford it and brought it to work. I remember clearly being told the damn thing would never fly – you just couldn’t get enough buttons on anything that small to equal the glorious flexibility of a K&E Log-Log Duplex Decitrig slide rule – with an ‘F’ scale instead of a ‘K’ scale if you were into designing radios. But who cared? Slide rules had no decimal points – you just had to know where to stick them, but the HP had ten significant digits and a decimal point in the right place. In no time at all, calculators had so many buttons for hard to calculate functions that evolution started selecting for engineers with skinny fingers that didn’t hit two buttons at a time (the sons of these same engineers now design mobile phone keyboards). Faster than you could say, ‘Log-Log Duplex Decitrig with Vector Hyperbolic Functions’, the slide rule died; there were no ceremonies or flowers and few mourners.
Back to the radios, heterodyne means to mix two frequencies together to produce a ‘beat’ frequency, namely the difference between the two. Superheterodyning, originally supersonic heterodyning, creates a beat frequency lower than the original signal; this solves a series of radio design problems and reduces amplifier power requirements.
Radios are marching to a different beat nowadays!
I was reading reports of the CES show in Las Vegas earlier this month. There were a great number of product announcements for cell phones, GPS, mobile TV, WiMAX, WiFi and the like and the fact that so many of them were being put into the same devices. I started thinking about the difficulties of stuffing so many radio technologies and so many frequencies into the same sardine can.
Think about them (in alphabetical order, please): Bluetooth (2.4 GHz), FM radio 87.5 – 108.0 MHz; GPS (1.1 – 1.6GHz); GSM (GPRS, EDGE -900MHz, 1800MHz); Mobile TV (MediaFLO, DVB, DMB – 200 – 800MHz); NFC (Near Field Communications -13.56 MHz); UMTS (WCDMA, HSPA, LTE – 2100MHz); UWB (Ultra-wideband – 3.1 -10.6GHz); Wi-Fi (2.4GHz, 5.8GHz); WiMAX (2.5GHz, 3.5GHz). I think I’ve got them all – at least ten basic categories, 16 or so technologies and, no matter how you count them, a whole lot of frequencies. If we put each of these into separate boxes, the size of the first superheterodyne radios, we would need a horse-drawn cart to carry them.
It seems we are moving inevitably towards the day when all of these technologies will have to share space in the same handheld device with cameras, screens, speakers, microphones, videos, music players, agendas, calculators and a long list of other components and applications.
Handset manufacturers are doing an incredible job of packing new functions into thinner and thinner, smaller and smaller devices, but there are limits. Since everything is implemented in hardware, physical and cost limits will soon be reached. Each new device and circuit adds cost, complexity and size.
What chip designers have done so far is amazing. The ASICs (application specific integrated circuits) that have been built to incorporate multi-band, multi-function circuitry are amazing, and there is a strong tendency to stick with these tried and true, thoroughly understood technologies. Nevertheless, the writing is on the wall.
One day soon, I expect the sardine-can design trend will grind to a halt and, faster than you can type a ‘UR kewl’ SMS, someone will come out with a commercial software defined radio device (SDR) mobile telephone and today’s technology will be deader than the slide rule. It’s simple; the manufacturing economies, smaller devices and increased flexibility of the new devices – once the bugs are worked out – will be unbeatable.
The software defined radio can, in principle, function in any frequency band and handle any signal modulation scheme by using software to process the signals. The earliest versions, some 15 years ago, were developed by the U.S. military to consolidate a variety of field communications devices into a single easily carried and maintained piece of equipment. The capabilities of these devices were far from those we would expect today to handle the sophisticated mobile communications we have become accustomed to, but they worked. There have been amateur, quite limited, versions of the SDR running on PCs with soundboards that can send and receive different radio signals using special software.
The proponents of SDR often see it as a first step towards the development of a cognitive radio, a radio that is sufficiently ‘intelligent’ to verify the available radio spectrum, compare it to the user’s communications needs, and dynamically configure and reconfigure cost/quality/frequency optimised communications sessions.
We can’t do it all yet, at least outside the lab, the processing speeds for the higher frequencies are just too fast for today’s processors to handle directly, power requirements for SDR radio frequency front-ends are still quite high and antennas that can efficiently handle such a wide range of frequencies are hard to design. Still, if I had to guess, I would say that in five years or less SDR will conquer as much as ten per cent of the market.
Oddly enough, the first problem, limited processing speeds for high frequency signals, has an old solution – superheterodyning. Remember? ‘Superhet’, to its close friends, works by lowering RF (radio frequencies) to the IF (intermediate frequency) range under 40 MHz. This relic from the early days of radio is still a mainstay of modern design.
The power problems are serious, but I expect they will yield in short order to advances in manufacturing and signal processing technologies. The antenna worries me more. Although great strides have been made in smart antenna design, the variety of technologies that must be accommodated is daunting. Mobile TV, LTE, UWB and GPS, for example, each pose separate, difficult, technically diverse problems for antenna designers.
Fortunately, as in the case of the sardine model for stuffing multiple mobile devices in the same can, nature has given us models for a new solution – porcupines and hedgehogs. It will be difficult to slip an antenna covered, bristly, device into your pocket or into a protective case, but as fashion shows have proved year after year, there is no shortage of weird designs to examine or weirder designers to work on the case.
Our next Connect-World Europe issue will be published later this month. The issue will be widely distributed to our reader base and, as well, at shows where we are one of the main media sponsors such as: GSM World Congress (Mobility World Congress), Barcelona, Spain (11-14 February), CeBit, London (4-9 March), IPTV World Forum, London, UK (12-14 March) and SOFNET, London, UK (21-24 April).
The theme of this issue of Connect-World Europe will be – From broadcast to broadband – it’s show time!
Distinctions among traditional services providers are increasingly blurred. Not so long ago, the last-mile technology service providers used essentially defined what they were and gave them control over their users – they ‘owned’ the subscribers to their services. Today, IP-based converged networks mean traditional voice, data or video service providers can – all of them – economically deliver any and all of the services offered by any other type of player. Nowadays, service providers may no longer own their customers; indeed – heresy of heresies – they may not even own their own networks. Skype, Google TV, MySpace and YouTube did not even exist a decade ago, yet they are a mighty threat to ICT sector business as usual.
Telcos offer IPTV and data, cablecos offer phone service and data and ISPs offer whatever service they can, and all are poaching upon territory that once belonged exclusively to the broadcasters. The competition is growing, although in many cases the income still isn’t – the traditional companies with the experience and the customers have an edge – but that is changing and so are the business models.
The profound changes IP networks bring to the sector are, perhaps, most clearly seen in the planning by nearly all service providers to provide entertainment, and in the rapid proliferation of entertainment delivery platforms. The impact upon the broadcast sector cannot easily be calculated, but everyone involved in delivering entertainment – content providers, the advertising industry, telcos, cablecos, ISPs and equipment manufacturers among others – is affected. As the sector ramps up to meet the demand for the new services, regulators, lawyers, manufacturers, carriers, service providers and the consumer will all have significant changes to deal with and difficult decisions to make.
The issue will examine the changes the sector – exemplified by, but not limited to, IPTV – as seen through the eyes of the regulators, service providers, manufacturers, indeed, all those struggling to make the transition to new models. The game is changing; it’s a new show.
Europe I 2008 Media Pack; Click here