The Journey of Radios From Hardware to Software

An anonymous reader writes "The New York Times is carrying a story all about the process of replacing radios with software. The article tells the tale of Vanu Bose, son of the man who started the Bose company, and his quest to bring software to what was previously a hardware-only enterprise. He met a lot of resistance in the 90s to his ideas, because processor technology was not up to the task. Now that technology has caught up with Vanu, his software (and other products like it) are increasingly replacing now-outdated hardware components. 'Well-established companies like Motorola and Ericsson now use elements of software-defined radio for their base stations. But Mr. Bose was the first to come to market with software that could handle multiple networks with the same equipment. Software radio appears to offer an elegant solution to what has been a vexing problem: how to have a single handset, like a cellphone, communicate across multiple networks. For instance, the G.S.M. standard, for global system for mobile communications, is used broadly in Europe, and most notably in the United States by AT&T.'"

An interesting idea

[FlyByPC]

It's amazing what can sometimes be done in software. You can make a simple AM-band transmitter using a microcontroller and two resistors -- with everything done in software. MCUs are fun!

Re:

[TheRealMindChild]

I could do it with a 1969 microwave. I am sure McGiver could do it with a rock and a used condom. No software needed!

Re:

[inflex]

Got schematic of this device?

Re:

[zippthorne]

His plan has three components, do you really need a pretty picture? It sounds like it'd be a pretty simple AM transmitter, and have lots and lots of out-of-band transmission.

Re:An interesting idea

[FlyByPC]

His plan has three components, do you really need a pretty picture? It sounds like it'd be a pretty simple AM transmitter, and have lots and lots of out-of-band transmission.

Well, yeah. Square wave outputs do tend to generate alllll sorts of harmonics. But it does technically work. If I were serious about it, I'd at least add a capacitor across the output, to make some attempt at filtration.

The "schematic" involved an 8-pin microprocessor, with two outputs each connected to a 1k resistor. The other ends of both resistors were connected to the antenna. Not very efficient, but as a proof of concept, it was a cool toy. Tuning was completely via software (tweak the timing loop to provide the correct waveform.)

You want pictures? Happy to oblige. (The idea was to see just how simple a transmitter I could make...)

http://www.intellectualism.org/electronics/schematic.jpg [intellectualism.org]

http://www.intellectualism.org/electronics/Closeup.jpg [intellectualism.org]

Re:

[Sigurd_Fafnersbane]

Why do you have two outputs from the IC?

Re:

[WED Fan]

Have you considered looking up the pinout guide and sussing it out yourself?

Re:

[FlyByPC]

To do voltage division. There are three possible voltage levels (since the resistors are equal): Both low (which results in a low output), both high (which results in a high output), and one high/one low, which results in a medium/neutral output.

Re:

[bdonalds]

Don't bring that radio to the airport!!!

Re:An interesting idea

[stevew]

My company has IP for a FPGA based FM radio that meets all FCC harmonics requirements - and it has the same kind of external requirements. - I believe in our case it's an RC on the TTL compatible output. This isn't software defined in the traditional meaning of the term - but the FPGA is implementing the same algorithms the software is implementing. So it's soft in the way an FPGA is soft.- but the idea is identical to the MPC version mentioned above as far as the outputs are concerned.

Bottom line - the harmonics can be taken care of by wave-shaping, i.e. you take the output load configuration into equation as you design the radio.

Re:An interesting pretty picture?

[aqk]

Oh, no-
You don't get away THAT easily.

Yes. I would like to see a picture.
Two resistors: A couple of zig-zigs with some 'Omega' symbols attached.
The ummm, third component: "And then a miracle happens"

Please elaborate with a simple schematic of the 3rd component.

Long ago I built a tube radio. The only part I could not have done easily myself was the glass, tungsten and vacuum crapola in the radio tubes. The rest was a snap.
Given a bit of time I could have built them too.

And this was long a

Re:

[zippthorne]

I think you've neglected the hard part of producing a functional vacuum tube. I'll give you a hint, it's the first part of the phrase "vacuum tube." You've also failed to mention what you'd use for a getter, but I doubt you'd be able to achieve the high vacuum necessary in the first place, so maintaining it is somewhat less of an issue.

The third component is a microprocessor. Those things have like..dozens of transistors. ;)

I suppose you could say that the software is the magic, but you don't ask for a s

Re:

[aqk]

As I said:
the only part I could not have done easily myself was the glass, tungsten and vacuum crapola in the radio tubes

I remember the Barium and other getters.. As a brief Chemistry student, always wanted to develop that stuff.

And most current microprocessors contain many manymore than like..dozens of transistors.

Like, like I said: Gimme the schematic. Of the hardware.

The software is easy. Or at least it used to be.
But then, when I think about it, could I have drawn a 100' copper wire

Re:

[BillyBlaze]

You can also make [erikyyy.de] an AM radio with your CRT monitor.

Re:

[darkshadow]

I used to pickup CB broadcasts on the built-in speakers on my monitor.

Re:

[nobaloney]

And I can make one with no resistors, no microcontrollers, a core from a roll of toilet paper, some fine wire, a steel razor blade and a piece of the so-called lead (it's really graphite) from a #2 pencil.

;)

Obvious Next Step

[Umbral Blot]

This seems like a "duh" improvement. If you can hard-wire some logic then clearly you can implement the same logic in software, gaining the ability to update the logic, or make it more flexible in other ways, at the cost of speed and, possibly, power. Haven't there been a number of other devices that have evolved in this way?

Re:

[kcbanner]

Yeah, firmware downloaded at driver load rather than flashed on a chip. I know its still software but the same idea.

Re:Obvious Next Step

[Anonymous Coward]

It's not quite a "duh" nor is it clear without apply a lot of brain-power. In an analog radio there is no "hard-wired logic", its just the physical properties of the components engineered to work with electromagnetic waves. Software radios are only possible because digital processors are cheap/small/fast enough to approximate what the analog components are physically doing by crunching some very clever math (FFTs) in real-time.

Re:

[Umbral Blot]

That is a logic, in the sense of a function that converts inputs to outputs in a regular way. Just not a boolean logic.

Re:

[Mathinker]

You seem to be making two assumptions whose validity is not obvious to me:

(1) All physical processes are deterministic.
(2) All deterministic problems are computable.

It is well known that there are lots of deterministic problems which are not computable [wikipedia.org].

If you somehow are making a deep philosophical statement that no problems derived from simulating physical reality are in this category of problems (a statement which as far as I can see needs justification), you still have the problem that they might well be

Re:Obvious Next Step

[Dun Malg]

That is a logic, in the sense of a function that converts inputs to outputs in a regular way. Just not a boolean logic.

No, that's not considered "logic" in the electronics world. "Logic" in the electronics sense means circuits that do useful work using two states (high/low) to represent true and false. These are considered digital systems, as opposed to analog systems, one of which is the classic coil-capacitor-diode AM radio receiver.

Software radios are awesome!

[mind21_98]

As long as they're not restricted to Windows (see: Winmodems) :D

Re:

[onineko]

Bad mind21_98, making me have flashbacks to dial-up tech support. No cookie.

AT+MS=V34
AT&F&C1&D2 /cry

It's the multiplexing

[Animats]

It's not that a single software-defined radio is all that important. It's that you can do the transforms on the incoming waveform and then extract N different channels with one signal processing system. That's what's been making cellular base stations go for almost two decades. (All the hard work is on the receive side; transmission is easy.)

First generation cellular base stations (i.e. AMPS) had one big analog card per channel, each heavily shielded from its neighbors. The amount of hardware required was huge, and cell sites tended not to be fully populated with channel cards, so they were easy to overload.

Then things started to go digital, with combinations of analog and DSP components processing the signal. Both GSM and CDMA inherently assume digital processing, and in early systems, hard-wired special purpose components were used. As CPUs get faster, there's a steady trend toward using general purpose CPUs.

It's still rare to actually process RF directly in software. Usually, there's a local oscillator and mixer to down-convert the desired band to a working IF frequency, which is then digitized and processed. So it's only necessary to digitize at maybe 10-100MHz, not up in the gigahertz range.

For lower bands, though, a true software RF receivers [rfspace.com] are available. These just suck up everything from 0 to 30MHz and digitize it. An attached PC does all the hard work.

Maybe use block frequency converters?

[Kadin2048]

The 'true software receivers' are interesting, but ultimately I think they're overkill once you get out of the HF bands. Maybe this will be one of those 'who needs more than 128k?' comments, but I really don't see any reason why you need to sample the RF directly when you're dealing with VHF or UHF, it just seems excessive. If you want to digitize a 1GHz input, you're going to need to sample it at least 2GHz, and probably significantly higher if you want to do any cool DSP-type stuff. That's gotta start doi

didn't someone ...

[sideswipe76]

Come up with a new division algorithm for sampling RF? Like, divide 3 instead of 2? I am not an EE but I remember reading it

Re:didn't someone ...

[Man On Pink Corner]

Something many people don't understand is that the Nyquist criterion applies to the bandwidth of the recovered signal, not to its carrier frequency. So if you want to recover a 10-kHz wide signal at 800 MHz, you don't need to sample at 1600 MHz... you just need to sample at 20 kHz, using an ADC with lots of front-end bandwidth.

That's an oversimplification, but it may be what you were thinking of.

Re:

[Sigurd_Fafnersbane]

Nyquist apply to the signal you want to process. If you want to do your filtering in the digital domain you will first have to capture both your wanted signal and the signals you seek to suppress. Otherwise you have your selectivity in your hard-ware and not in your software.

The function of "ADC with lots of front-end bandwidth" is what the hardware in the RF front-end is doing in a traditional radio system.

In GSM you must be able to detect your own signal at say -108dBm while you have a blocker at 0d

Re:

[Agripa]

In GSM you must be able to detect your own signal at say -108dBm while you have a blocker at 0dBm. Every 3dB is a doubling in power, 0dBm is 1mW so -108dBm is 1/(2^36)=1.45e-11 mW. If you need 3 bit s/n in your wanted signal to decode it you will need at least 3+36 bits to represent the samples.

Resolving the 108 dB dynamic range requires 18 bits and not 36. The RF energy is measured in power which is impedance agnostic while A/D and D/A converters deal with voltages. Of course even a converter with 18 bit

Re:

[Sigurd_Fafnersbane]

You are right about the 18 bits for the dynamic range. The three bits for having enough s/n of the wanted signal is still needed though so it would be 21 bit.

You are also right that this is slightly academic since no-one would implement a handset in this way.

I am also rather sure that even the base-station in the story is using a band-select filter in front of the LNA to limit the signal to in-band blockers.

Re:

[Agripa]

Base stations are getting better all of the time with improvements in the processors and converters. The last time I checked the most cost effective designs split the frequency band into 20 to 40 MHz slices for conversion.

Re:

[Sigurd_Fafnersbane]

Limiting your in-put bandwidth to 20-40MHz is a big help against blocking signals. The most power-full blockers for a base-station will either be out-of-band blockers like TV broad-casting, radar or other applications or it will be handsets from competing cellular providers that operate outside the providers own licensed band.

It would make sense for an operator to order base-stations with a duplex filter only wide enough to cover the frequencies for which the operator have a license.

All modern handsets

Re:

[Agripa]

Since a handset will move around and can roam between multiple operators the requirements for a handset is bigger. You need the full dynamic range since yout own operator may have weaker signals than other carriers in your present cell and you still need to decode yuor own channel.

Handsets certainly face a different set of challenges but having to only transmit and receive on a single channel or pair helps a lot. For many years now even completely analog receivers often have had varactor tuned RF filters b

Re:

[gregorio]

Something many people don't understand is that the Nyquist criterion applies to the bandwidth of the recovered signal, not to its carrier frequency. So if you want to recover a 10-kHz wide signal at 800 MHz, you don't need to sample at 1600 MHz... you just need to sample at 20 kHz, using an ADC with lots of front-end bandwidth.

If your radio is entirely based on software, then you'll need to do the filtering and de-modulation using digital filters and that will handle the "entire" wave and will actually nee

Re:

[LM741N]

If what you say is true, then how do you channelize your wide band receiver?

Somewhere there has to be an analog filter that is one channel wide. Cellular handsets, whether GSM or CDMA use SAW filters for that job and synthesizers to mix the desired signal down to the SAW filter freq.

Re:

[Sigurd_Fafnersbane]

You can get around the channel select SAW filter by using direct conversion.

In a modern handset (not software radio) you would use direct conversion meaning that you would create two sets of mixing products between your incoming signal and two copies of an LO running at the carrier frequency 90 degrees out of phase with each other.

The desired signal would be represented by the resulting complex signal from the two mixers (real and imaginary part) and the output from the mixers will be low pass filtered

Re:

[LM741N]

High band CDMA is 1930 to 1990Mhz. So in your already complex DC chip you are going to put an ADC running at a multiple of 60Mhz? In your dreams. The technologies required are different for high speed logic and low noise figure microwave. SiGe comes close.

In real direct conversion handsets there still is a synthesizer, there still is filtering to meet Adjacent Channel Power (ACP) requirements and strong signals out of band as these radios are full duplex. So you really haven't gained much vs. the tradi

Re:

[Sigurd_Fafnersbane]

Adjacent Channel Power requirements can be handled by the on-chip low-pass filters. In CDMA2000 you have a channel bandwidth of around 1200kHz so you implement channel select low-pass filters with 600kHz bandwidth which is very do-able on-chip. These filters are analogue (they have to be before the A/D).

Re:

[LM741N]

You still need a duplexer (I don't know if CDMA2000 uses SAW based ones), LNA, some sort of gain. ADC's don't work with microvolt signals I don't believe. Otherwise they would have to have incredible noise figures. Something ahead of them has to establish the NF and provide gain.

Re:

[wramsdel]

If you want to digitize a 1GHz input, you're going to need to sample it at least 2GHz

Nope, not quite. If you want to digitize a signal with a bandwidth of 1 GHz, you'd need to sample it at at least 2 GHz. You can sample a signal with a 1 GHz center frequency at significantly less than 2 GHz as long as the signal is sufficiently band-limited (to prevent aliasing) and the bandwidth of the data converter and front-end are greater than 1 GHz. It's not uncommon to find affordable ADCs with sample rates around

Re:

[dlinear]

The problem with block downcoverters is that that is not truly a software radio and limits flexibility immediately, by reducing the spectrum available. This is the limiting factor of an modern day SDR system. Without the block downcoverters though it's hard to keep unwanted signals out (CDMA with a higher signal power then WiFi for example). But with modern day hardware and signal processing capabilities a novel prefilter can be designed, say with 20MHz tuning blocks that are to be completely digitized by a

Two Words

[keithmo]

GNU Radio [gnu.org].

Re:

[Rorschach1]

I'm not sure if they're going to be represented this year, but I've seen some GNU Radio stuff shown at the annual ARRL/TAPR Digital Communications Conference, which happens to be coming up next week in Hartford, CT. I see a couple of SDR-related topics on the schedule, including the Sunday seminar.

Even if you're not an amateur radio operator, it's worth checking out if you're interested in SDR. And the banquet speaker this year is Bruce Perens of Debian and OSI fame.

http://www.tapr.org/dcc [tapr.org]

Re:

[mako1138]

GNU Radio is also a good example of the cost downside to SDR. The basic board, the USRP [ettus.com], costs $700. And then you gotta buy daughterboards.

I figure in a few more years we'll get cheap SDR.

Re:Two Words

[FrostedWheat]

You can use a capture card with a BT878 chip as a cheap entry into SDR and GNU Radio. See Here [domenech.org]

The card I have didn't require any kind of modifications, and I've successfully captured signals all the way up to about 400kHz directly from the air simply using a long wire, including digital radio (the unfortunately named DRM [wikipedia.org]) signals.

Re:

[Duncan Blackthorne]

What I find interesting (and horrifying at the same time) from that site, is that the MPAA and the FCC are actually discussing legally limiting who can purchase fast ADCs in order to protect their IP. So, what, if they got their way, I'd have to get some sort of license to purchase an integrated circuit because I might use it to build an HDTV receiver that they can't control? What a bunch of jerks!

Three Letters

[jbengt]

FCC
/http://www.softwarefreedom.org/resources/2007/fcc-sdr-whitepaper.html/ [slashdot.org]
http://www.dslreports.com/forum/r18623835-FCC-says-freeopen-source-software-radio-drivers-are-OK/ [dslreports.com]

A little too much feature creep.

[raydubicki]

Companies seem to forget that there is still a market for the simple. It took me two weeks of looking to find a piece of stand alone desktop equipment that satisfactorily met the following requirements:

1) AM/FM radio
2) AC plug
3) Headphone jack
4) Let's try keeping it under $30
5) Doesn't look like crap.

Sometimes, all you want is to listen to the baseball game on the radio. I didn't want to stream online (especially paying the usurious fees charged by MLB). I didn't want to change batteries. I didn

Re:

[Propaganda13]

Next thing you know, they'll want to communicate with these radios.

Re:A little too much feature creep.

[FooAtWFU]

Dear Mr. Barely Glanced at the Fine Summary:

This is about radios in a variety of communication devices. Like cell phones. And cell phone towers. Especially cell phone towers. Not so much your Sony Walkman et al.

Looking in the wrong section.

[zippthorne]

Buy an alarm clock from a drug store. They often have AM/FM radios thrown in there.

Why does it have to "not look like crap?" Why can't it look like you didn't overspend on sony quality?

Now.. whatever happened to mass-produced small crystal radios? Those'd be interesting for hurricane kits, especially if they could tune the broadcast FM band (but obviously not as an FM receiver. You can still hear FM with an AM reciever, it just doesn't sound all that great. Voice is fine, though.)

Re:

[ByteSlicer]

Buy an alarm clock from a drug store. They often have AM/FM radios thrown in there.

I never saw an alarm clock with a headphone jack (like the parent post requested). It would defeat the purpose of an alarm clock, I guess ;)

Crystal radios ??

[the_rajah]

Are not particularly practical for FM. Yes, an AM radio can demodulate FM through a technique known as "slope detection". Crystal radios bandwidth slope is so spread out that, even if crystal radios worked well at 88 to 108 MHz frequencies, the recovered modulation would be so small as to not be usable, even though that's wide-band FM. Years ago I had some reasonable luck receiving FM broadcast signals with a home built super-regenerative receiver using a single tube, but that's far from being a crystal set

Re:

[Varitek]

especially paying the usurious fees charged by MLB

MLB's audio service is $15 a year, for every game. It's a bargain.

I read this and...

[Nom du Keyboard]

replacing radios with software.

I read this and end up believing that my next radio will be delivered to me as a software printout on a sheet of paper.

Re:

[Dogtanian]

I read this and end up believing that my next radio will be delivered to me as a software printout on a sheet of paper.

Typing in program listings? I thought that had pretty much died out by the end of the 1980s, and thank God for that. It was a PITA back then, can you imagine how long it would take you to type in software nowadays? If we generously assume that one can fit a 16KB BASIC listing onto one A4/legal-sized page, a 16MB program (pretty small by today's standards) would require 1000 pages!

(Meanwhile, a double-layer DVD's worth of data would need roughly half a million pages, so you'd need a small truck to deliver

Bose blows

[xs650]

I hope it's better than his fathers hardware. Overpriced crap that only clueless people who like to pay too much for popular brand name products buy. And unavoidably bought by millions of car buyers that don't have a choice.

Mod parent up

[Paktu]

This is absolutely true. Bose products are junk, but years of marketing have convinced the public that they sell "premium" sound equipment.

Re:

[zippthorne]

They do do some clever audio munging^h^h^h^h^h^h^hprocessing to make it sound "fuller." And they claim to do it in hardware ironically, especially as they don't do anything that couldn't be done with cheap DSP.

Re:

[ageoffri]

Truer words have rarely been posted here. For people who care about audio quality Bose is a complete joke.

No highs, no lows, gotta be Bose.

Re:Bose blows

[dreddnott]

I first heard this as a charming little poem:

Got no highs? Got no lows?
Only midrange! Must be Bose.

Re:

[tjstork]

If Bose is not a quality audio solution, then who is? Are we back to Sony, Pioneer? Or is there some other premium band? And, what do you even look for? Bose at least plays there stuff in a store, you can hear it, and it sounds pretty good. So, what kind of music do you listen to that demands something else?

Everyone says Bose sucks, but no one ever says, well, who is better.

Also, what's the -best- sound card for hardware wavetable MIDI synthesis?

Re:

[zerocool^]

Ok, I'll bite.

I worked years ago in the Audio department at a best buy. I don't know the current state of home electronics, but I know what the mid-range state of electronics was about, oh, 8 years ago.

If Bose is not a quality audio solution, then who is? Are we back to Sony, Pioneer?

I'd rather have EITHER of those brands of speakers over bose. Any day. We also sold Cerwin Vega and JBL and yamaha, and I'd rather have any of those. The only brand that I'd buy bose over was "KLH", which was our generic h

What's that stuff between 100-250Hz? Must be Bose.

[gmarsh]

"No highs, no lows..."

Having actually swept set of Bose 901's with Audio Precision gear and a calibrated mic, I can tell you that they've got one of the flattest responses I've seen. (Assuming of course you use the big equalizer box that comes with it...)

Problem is people nowadays have become accustomed to "XLOUDPHATDXBASS". People listen to portable radios with the "loudness" switch set to the on position. They listen to radio stations which heavily process their audio with excessive bass and treble, with

Re:

[xs650]

Parent obviously maked flamebait by some wanker who hasn't bought several cars where the sound system included in the price of the car was by Bloes.

Cell Phones

[rebelcan]

I'd really like to see this sort of thing being implemented in cell phones. Unfortunately, where I live, the provier with the best rate plans uses CDMA for their network. All the cool phones I'd like to have use GSM. Having a phone that could switch between the two would be freaking awesome.

Re:

[ypps]

Imagine a system where there is no GSM or UMTS or WiMax or WiFi. Just one single radio network that automatically optimizes the communication for each terminal in the network, whether it's in the middle of a city or out at sea. A network where a user with a particular sim-card is free to choose which company or companies it want to use with that sim-card (no more roaming abroad or tie-in with a certain carrier).

That part about the sim-cards will come true approximately when hell freezes over, pigs fly and W

Re:

[DDLKermit007]

I was talking to a Sprint Rep a month back when I was setting up a customer with EV-DO since they don't get Cable/DSL, and Satalite is a joke. I was bitching about their lack of GSM in their phones. Turns out they carry Blackberry phones with GSM radios in them now. No idea how well they work personally (not to mention I'll never buy a BB), but it is nice to see that some phone makers are getting smart enough to know they need to support both if they are going to deal with CDMA.

Re:

[JoeSavage]

I presume you're speaking of the BlackBerry 8830, which has a dual-band GSM radio for the EGSM/DCS bands only. This means it doesn't work in America where they use GSM850/PCS bands. So, unfortunately, you can't pop in a T-Mobile or AT&T sim card and use it on their networks. But, as I work for a company that has standardized on Verizon as their corporate wireless provider, it's the only option if you want to have a single handset that works most everywhere.

Re:

[TooMuchToDo]

Our company just standardized on T-Mobile for our Blackberry users, as the new Blackberry Curve can take advantage of T-mobile@Home's Wifi phone server. While Verizon has a much larger network then T-Mobile, we can now just place a Wifi access point anywhere we need better coverage (branch offices, basement of HQ, home offices of people, etc).

Re:

[DDLKermit007]

Oh I was more concerned with international traveling (I do a little bit of it to say the least). Kinda disappointing to hear about the lack of US support from GSM side though.

Re:

[arivanov]

It is not just radio. Both have a big protocol stack most of which is in real time behind the radio. When you add up all the resources necessary as well as all the fees to leeches like Qualcom it stops making sense. This is besides the fact that the non-GSM networks are not going to be particularly happy to allow phones that can do GSM as well. As far as they are concerned that is a sure way to leak customers.

gnuradio

[siddesu]

actually, there is gnuradio, which is a project (including available hardware) that lets people experiment with software radio. there are quite a few interesting things the folks from the project have done.

if anyone's interested, more here:
http://www.gnu.org/software/gnuradio/doc/exploring-gnuradio.html [gnu.org]

and a bunch of links on wikipedia:
http://en.wikipedia.org/wiki/Gnuradio [wikipedia.org]

Not the first time I noticed this

[Duncan Blackthorne]

I think the title of this posting could be construed as a bit misleading, in that it says 'radio' but when you read the attributed article, they're talking about cellphones, not things like broadcast radio or other areas where RF transmission and reception are necessary. It may or may not be obvious to anyone, but there's no way that tuned RF circuits can be completely eliminated, at least if you're talking about over-the-air transmissions; you still need to at least provide amplification (which must be a tuned circuit) and impedance-match to your antenna (which again must be a tuned circuit).

Re:

[Jott42]

RF reception and transmissio is very important for cellphones. And tuned circuits can be eliminated completely, but this puts ridiculous demands on the AD/DA-converters for most real world applications. The DA-converter could leave enough power to drive the antenna, and impedance matching could be broadband, and thus not tuned. A more practical application is to have a wideband frontend, and then sample a complete band, such as the 2.45 GHz ISM-band, and leave all the channel filters for different aplicati

Re:

[RKBA]

Only for transmitting, not receiving. When I was a young child I made a serviceable AM radio receiver with nothing more than a Gillette Blue Blade (old fashioned double edged razor blade with a silicon coating) to act as a rectifier, a piece of wire for an antenna, and a cheap 99 cent ear piece to hear with. Fortunately for me, there was only one local station broadcasting with enough power to be heard through my jury-rigged radio receiver (KCOK in Tulare, California) otherwise I'd have had all sorts of int

Vanu Bose's bitter battle with MIT

[ortholattice]

MIT owns the software radio patent, but Vanu thinks he should pay no royalties because he was a key developer of the technology, which formed the basis for his PhD thesis. This [rediff.com] is an old article (1999), but I couldn't find a followup on the outcome.

In older days, his father Amar Bose's company was made possible because MIT let him have the patent for nothing. Now that Amar is (presumably) a billionaire from his high profit-margin products that gross $600 million a year, he has donated $6 million back to

Re:

[pimpimpim]

Hmm, where I did my PhD there were specific rules on who gets to keep the patent (the institute itself, as far as I know). I'd think that of all places MIT has a probably very well worked out contract for this, which he agreed to when starting to work there. With his background, I can hardly imagine he didn't have the knowledge to find this out before starting at MIT, it will be hard for him to get the patent.

As for paying no royalties, I guess it's not the same as owning the patent. I wonder how it works

Re:

[Anonymous Coward]

According to this [mit.edu], it wasn't the royalties, it was that MIT demanded equity in the startup.

To paraphrase the argument, MIT its entitled to royalties, which are tied to the value of the patent, but not equity, since the company's value is more than just the patent (unless that company exists only to hold the patent).

Re:

[RGRistroph]

Our constitution allows for patents to be awarded to inventors, and an inventor is a type of human being. An institute cannot be an inventor. Of course thesis topics are not developed in a vaccuum, but if the thesis advisor was a co-inventor then just put his name on the patent too.

When places such as MIT demand a part of any patent before it is actually invented, and other corporations demand a piece of any patent even if the invention was developed outside of their environment, it corrupts the whole pu

Emergency Communications

[Detritus]

I'd like to see the technology used to solve some of the inter-agency communications roadblocks that afflict the USA. Every agency has their own frequencies, protocols and hardware. In an emergency, they often find that they can't talk to any of the other responders. In addition, it would be great if the radios could work with the current cellular networks. This is one of the reasons that the military is investing money in SDR. Many people still remember the soldiers in Grenada who had to request close air support by using a phone card and making a call on a local wireline phone to Fort Bragg.

Re:

[grumling]

That's kind of the point. You need to talk to the State Police dispatcher to get a highway closed, just load up the Motorola SMARTNET protocol, pick the frequency (or have the radio search) and push the button. Need to contact a hospital for advice on what to do with the guy hopped up on PCP? Load up the P-25 profile and squeeze the pickle. Need to find out where you are? Open up the GPS reciever window. Want to get a Red Cross canteen to the fire line? Dial up the local ARES net and send the request.

BTW th

Re:

[Mr Hoffman]

Cellphones aren't viable for use in emergency services. The towers jam up, or tip over, or loose power. Or all three. Sure, having a cellphone is handy for patching patient information to a hospital or ordering up sandwiches and beverages for the emergency crews. But typical cellphone handsets just aren't built for rough service (eg: getting hit with a fire hose, falling off the running board of a moving fire truck), nor are cellular networks known for disaster-tolerance, nor are cellphones viable for h

Re:

[Detritus]

In my area, the state police are on low-band, local police are on high-band or UHF T-band, and the fire department is on UHF T-band. Some agencies are moving to 800 MHz. The feds are on their own set of bands, distinct from state and local agencies. None of them are interoperable.

The DoD's new Software-based Radio

[flydpnkrtn]

The Joint Tactical Radio System (JTRS or 'jitters') is currently being tested by the US Army... it aims to be "everything in one box," and it was "originally planned to span a frequency range of 2 megahertz to 2 gigahertz. JTRS has been expanded to frequencies above 2 GHz to satisfy space communications requirements"

That's a direct quote from the Wikipedia article (which looks like it's pretty accurate), located here: http://en.wikipedia.org/wiki/JTRS [wikipedia.org]

I'm in the Army, and buddies of mine have played with it and can attest that "it's pretty cool" :)

You should see the aerial..

[cheros]

If you think that's impressive, think about what has to happen to an aerial to support all those different frequencies.

The aerials for these things are mostly ignored but are nothing short of impressive.

Re:

[flydpnkrtn]

Yes that does sound interesting... I've never actually gotten to play with a JTRS unfortunately, I've only heard about them.

Re:

[hughk]

It sounds like a wonderful system when it works and a maintenance disaster waiting to happen in the field. It is very difficult to produce something for the army, navy and the airforce. I suspect it will work probably at fixed installations but remain somewhat tricky elsewhere.

Software radio scaners

[rec9140]

Any one interested in creating a new breed of software based radio scanners (those radios used to monitor police, fire, ems, and other signals) for modes not supported on current scanners or to add features can bring their skills to:

http://groups.yahoo.com/group/gnu_radio_scanner/ [yahoo.com]

This is a group looking to build on the GNU Radio blocks.

GNU Radio

[wikinerd]

How come an article like this does not contain a link to GNU Radio [gnu.org]?

Software replacing hardware...

[evilviper]

In theory, software (solid-state digital circuits) has huge advantages over hardware. Software offers extreme flexibility, no wear-and-tear, etc. If it worked as well as it should, in theory, there wouldn't be mechanical linkages just about anywhere, anymore. All the controls in your car would be electric, and a significant portion of your car's engine would be gone (no more cam shaft). The same would be true of most everything... If not replacing significant numbers of mechanical components, at least using software to precisely control it, and getting much better efficiency as a result. Yes, your refrigerator, microwave, etc. could all greatly benefit from software control.

There are just two big problems that have made software control a non-starter.

First is customization. Put a spring in the mechanics of an engine, and I can replace it with a shorter/longer/stronger/weaker spring. I can heat it up to weaken it, grind it down, etc... With software, you are given a black box, binary-only, with no documentation on how it works, and definitely no common interface to access and modify it. So every time car companies add another function to their cars' onboard computers, and take away mechanical systems, there's extreme resistance, as buyers know they're out of the loop, and if they want to adjust anything, or if something should go wrong, they can only take it to the select few company-blessed shops, which have paid the necessary bribes to get enough info to do just a few basic things with the onboard computer. And you're entirely screwed if you want more changes than that, because the company doesn't WANT you to, and without man millions of dollars on the line, you're not even a blip on their radar.

Despite what many believe, cost is almost never a problem. For low cost products, low-end micro-controllers can be found for pennies, and even cheaper are the basic I/O elements like thermistors, power meters, transistors, relays, etc. Yet even the dirt cheap processors sold today can do many millions of calculations per second, far faster than could be needed for damn near any products.

Second, and perhaps more important, is reliability. Computer hardware is EXTREMELY reliable. You can go buy a dirt cheap commodity CPU, RAM and MOBO, and be pretty damn sure it will run for 20 years without a SINGLE error. The only big exception to this is power supplies... a marginal one, not supplying enough power will cause a crash, but that generallyonly happens in the case of the cheapest no-name junk. What's more, go up a small step to a high quality MOBO, ECC RAM, redundant PSUs, UPS, etc., and you'll never ever see a hardware-induced glitch.

The reliability problem comes ENTIRELY from poor software, and mostly commonly available kernels, at that. People don't want to believe that, but the facts are that computers are 100% pure math machines, and math is 100% accurate. A computer will do exactly what you tell it to do, but most people are trying to program their computer through several million lines of indirection... If you write, in hex, a simple loop with a bit of processing, a computer will run it error-free, from here until doomsday, but programing a complex system in hex is much too hard, and human programmers aren't perfect enough to do so.

The only real possibility to ensure reliability with reasonable development time is something very much like a micro-kernel. You need a tiny bit (a few hundred KBs) of EXTREMELY-thoroughly audited code, that can very strictly manage memory, do strict input and bounds checking, carefully manage communications between independent modules of code, instantly tear-down and restart any bit of code which shows the slightest signs of an error, and also strictly ensuring real-time operation.

I'm not endorsing any product here. The fact is nothing like this exists. That is why we aren't seeing mechanical systems having components being replaced by software as quickly as they can be redesigned. Open source operating systems

Re:

[smallfries]

First is customization. Put a spring in the mechanics of an engine, and I can replace it with a shorter/longer/stronger/weaker spring. I can heat it up to weaken it, grind it down, etc... With software, you are given a black box, binary-only, with no documentation on how it works, and definitely no common interface to access and modify it.

You seem to be arguing that hardware is more flexible than software - but surely you are not that stupid?
A) How many cellphones now have user customizable parts like "spri

Re:

[evilviper]

You seem to not have read past the sentence you're quoting...

Re:

[smallfries]

If you try and take all sides to an argument then you're still wrong at least once.

SDR has been around for years

[BbMaj7]

Advanced Communications Technologies (ACT) in Australia was doing this with GSM back in 2000 (probably before). AFAICT they never did manage to make it work. Spent millions.

Anyone from ACT/SDR reading this could perhaps fill in more details.

I think the company is out of business now. Here's an early press release:

http://www.rmit.edu.au/browse/News%20and%20Events%2FFor%20Media%2FNews%2Fby%20date%2F2000%2F;ID=poid0yrprddq;STATUS=A [rmit.edu.au]