Yes, basically what you need is a tuner, a digitizer, and enough CPU to do the job. The last one can be the killer, though.
Here's how you can receive multiple signals at once with one tuner - let's pick on ordinary FM, and let's say I want to receive 95.1 MHz and 96.3 MHz.
The first requirement is that the two signals in question have to be reasonably close in strength - if one signal is coming in at -60 dBm (one millionth of a milliwatt) and the other at -120 dBm (one millionth of one millionth of a milliwatt) it's not going to work. But let's say both signals are coming in at -100 dBm, so there isn't a problem there.
OK, so what I do is make a receiver that will amplify all signals around 95.7 Mhz (half-way between the two) and downshift that to a convenient IF, say 10.7 MHz. Ideally, I'd want to bandwidth limit the signal to about 1.5 Mhz - that way I get both the signals I want, and not much else.
So my receiver is now outputting a signal at 0 dBm (1 milliwatt). If I look at that signal on my spectrum analzyer, I see 2 peaks - one at 10.1 MHz (the signal that used to be 95.1 Mhz), and one at 11.6 Mhz (the signal that used to be at 96.3 Mhz).
OK, now I digitize the signal. I need to sample at more than 3 Msample/sec (Nyquist's criterion) - any less and the two signals will be "folded" into one, and it's game over. To keep it simple, I will digitize the signal at 40 MSample/sec.
Now, I have a bitstream that contains the information for both signals. First, I multiply the signal by a mathematically generated cosine and sine wave at 10.1 MHz. This will give me two signals - I and Q. I is the "in phase" signal - the product of the cosine signal and the digitized signal. Q is the "quadrature" signal - it is 90 degrees, or a quarter circle out of phase with "in phase" signal (hence the name quadrature).
Next, I lowpass the signal - I run I and Q through a digital filter that removes all frequency components above 75 KHz.
Now, I compute a four-quadrant arctan() on the I and Q filters - this gives me the phase angle of the signal. I then differentiate that signal - subtract each sample from the previous sample. That gives me the instantanious frequency of the 95.1 MHz carrier - and there's your audio (if you want stereo I have to go trhough a few more steps....)
Now, I do the exact same thing, except this time I use a mathematically generated 11.6 MHz cosine/sine wave. The end result is the 96.3 MHz signal.
Now, as you can guess, that's a lot of math. Hoever, there are chips that do all of that for you. The Intersil 50216 I keep mentioning has 4 independant sections, each of which will do all of those steps, on a 40 MHz signal (or faster), in real time. If you do the math, the chip works out to about 5 to 10 billion operations a second, for 10 watts.
Chips like the 50216 are used by cellular folks - the idea is they grab the entire cellular band, digitize it, and the pull the calls out of the mix. You have only 1 drify, nasty analog receiver section, and hundreds of nice, stable digital sections.
There are a few problems with this approach, however:
1) The wider the receiver, the more noise it picks up. A receiver that is listening to 1 MHz of the spectrum picks up roughtly ten times as much noise as a receiver listening to 100 kHz of spectrum. That extra noise limits what you can tune in. 2) Strong signals in your receiver's bandwidth will prevent you from hearing weak signals - this is called "desense". It's one of the things that makes CDMA and TDMA cellular harder to do than dumb old AMPS - a phone near the tower has to be told to speak softly, so that the tower can hear distant phones. 3) Faster is harder - digitizing a 455 kHz IF is dirt cheap. Digitizing a 10.7 MHz IF is harder. Digitizing a 100 MHz IF to be able to cover the whole cell band is a bitch.
(Hey Meirowsky!) Other possible sources for gear
on
HDTV via GNU Radio
·
· Score: 1
I wonder if my buddy at Spectrum Signal Processing is reading this thread - perhaps they might be able to release a slightly lower cost solution to this.
Actually, 20MHz isn't so bad - I work with 40 Msample/sec 12-bit flash converters, and there are 100 Msample/sec 12-bit flash converters on the market.
However, you DON'T build things like this with your brother's wood-burning kit and a old nail - These parts come in surface mount packages, and your board has to be carefully designed to maintain proper impedance matching on the RF traces, as well as having excellent grounding (RF and digital grounds meeting at one and only one point, ground planes cut as needed to prevent current loops, etc.).
Lastly, you need a proper dithering circuit to introduce noise equivelent to 1/2 of the least significant bit, in order to shape the quantization noise out of the frequencies of interest. Otherwise, you end up throwing away a couple of bits of resolution.
Those are the sorts of things you have top-notch RF designers laying out, and a top-notch fab build for you - either by having such a fab working for you, or by contracting it out.
You don't get harmonics (frequencies that are related to the fundimental by an integer multiple), you get mixing products, also known as "sum and difference".
You get harmonics when you feed a single signal into a non-linear element - feed f1 in, get f1, 2*f1, 3*f1, 4*f1,... out. This is commonly used in tranmsitters to allow the use of a lower-frequency crystal to generate higher frequency carriers - you use a 10 MHz crystal, and the feed it into a non-linear element such as a squaring amp, and pick off the tenth harmonic to get 100 MHz.
Mixing involves feeding 2 signals f1 and f2 into a multiplier - you get f1, f2, f1-f2, and f1+f2 out. Mixing allows changing a frequency by a non-integer relationship. You have heard this used in the voice distorters used on TV to mask mob informants - they mix the person's voice with a low-frequency signal to change the pitch of the speaker's voice. This is also the basis of any modern superheterodyne receiver - you mix two different (heterogenous) signals together.
The idea is to take the signal from whatever frequency it is on, and move it to the frequency you have designed your circuit to work at - an "intermediate frequency", or IF. You then filter the signal, amplify it to a specified level, and repeat as necessary to get the signal where you want it. For example, a standard FM radio might go from the broadcast frequency to a 10.7 MHz first IF, then to a 455 kHz second IF, then finally to the FM detector circuit.
Eventually, in a design like GnuRadio, you sample the signal. The tricky bit is you have to sample at a frequency not less than twice the highest bandwidth in the signal (Nyquist's criterion). For a 6MHz wide TV signal, that means you need to sample at not less than 12 million samples per second.
Then, for a system like HDTV, you are dealing with a complex signal - and I mean complex as in sqrt(-1), not just as in "not simple" - you need both the real (in-phase, or I signal - the "real" part) and the quadrature (out-of-phase, or Q signal - the imaginary part). The signal is 8VSB - eight level vestigial sideband. So you have to do carrier recovery and tracking (because the carrier itself was removed - that is what makes it a sideband signal), then you have to convert the signals from the analog RF signal into one of 8 levels (slicing is the technical term). However, you have to slice accurately in 2 dimensions - you have to slice at the correct level (is.7 volts a 6 or a 5?), and you have to slice at the correct time (the symbols are only defined at certain times - any other time the signal isn't valid, it is a blend of the current and the (next|previous) symbol - what is called inter-symbol interference or ISI). So you have to do symbol tracking - figuring out when to sample, and at what levels to slice.
Finally, once you have a symbol stream, you then have to do all the foward error correction - you have to de-interleave the signal (think of unshuffling a deck of cards) - interleaving is done so that a transient interference (like a lightning strike) doesn't scramble adjacent bits - the errors are spread out.
Then you do your block error correction - this can undo a small number of bit errors per block (again, that's why you interleave the signal: so that block error correction needs to only correct a few bit errors per block).
Then you do some more protocol recovery, and you have an MPEG stream.
Normally, you do this sort of stuff with a big FPGA or an ASIC. The GnuRadio folks are doing it in software. The up side is that you can more easily tweak the code. The downside is that you are not going to be real-time for a few more iterations of Moore's "Law".
What gets to be REALLY fun is when, in addition to all of the above, you have to compute parametrics on the signal - not just recover the bits, but measure how far out of ideal the signal was (that's the sort of stuff I do for a living.) When you do that, you have to do all of the above, THEN once you have an error corrected bit stream you have to regenerate an ideal signal and compare the received signal against it, and measure how far away from the ideal signal the real signal is.
And THAT is when you start using multi-GHz processors, 10 million gate FPGAs, big-ass DSPs, and all sorts of other fun stuff.
Well, I DO do this stuff for a living, as well as being a computer geek and a ham.
But really, $1300 for the digitizer card is a bit steep - I work with a system using a 40 MSamp/sec 12 bit flash converter and Intersil 50214. The Intersil is about $30, and I don't think the flash converter is much more. Add a $50 FPGA to do the interfacing to the PCI bus, and you could do scatter-gather busmastering capture to the main system pretty easily.
Use a $50 Intersil 50216, and you could do most of the heavy lifting with it - Final IF filtering, I/Q recovery, post-detection filtering, symbol tracking, etc. That would remove a lot of the CPU load from the system, possibly allowing for real-time aquisition and decode.
Go to one of the board fab houses, and you could probably get a board built for about $500, maybe less.
Considering that people are spending $500 for video cards, this might not be so bad.
Man, I wish the Gnu folks would build their own hardware card rather than the card they are currently using - it's quite expensive.
I'd love to see them put a decent FPGA, an Intersil 50216 4 channel digital downconverter, and a nice 60 Msample/sec 12 bit flash A/D converter on the card - they could do that for a bill of materials of about US$200, and have enough power to do the capture properly.
Before you say "Fine - why don't YOU design it?": I'd love to get more involved in GnuRadio, but I'm afraid of potential conflicts of interest both ways - contaminating GnuRadio with my professional work and possibly exposing my employer to problems with GPL infringment.
Also, is anybody big in the Gnu Radio project going to be at IWCE (International Wireless Convenention and Exposition) March 10 - 14? If so, where? I'm getting in on an exhibitor's badge - maybe I could get pictures?
1) Start learning Tae Kwon Do - it's a better fit than Karate. 2) As soon as you are old enough, buy lots of AR-15's and street sweepers. Hold them until the Democrats get into power. Sell for big profit. 3) Save as much money as you can - on your first job, put all your overtime pay into investments (see #2, above). 4) Don't do business with United Engines Specialists in Wichita - they don't understand how to connect an oil pump. 5) Get Mom to stop smoking. Failing that, after her first bought with cancer, insist she be checked every six months by a competent oncologist. 6) Don't go to the hospital in Ark City (see #5). 7) Learn Z80 assembly, write a BASIC interpreter, release it to all who wish to use it, with the proviso that they have to give others the same distribution rights you gave them.
First, viewport vs. workspaces - the arguement was that since workspaces and viewports "did the same thing" (let you have more deskspace than desktop) there was a redundancy. So, the Gnome team eliminated one. I feel they eliminated the wrong one.
I've tried running Sawfish, and it crashes horribly. This makes getting my beloved viewports back somewhat more difficult.
"People don't hate computers, they hate lazy programmers." The problem is that it is far easier to remove features than to properly manage them so that newbies have what they need, and power users have what they want.
"Good programmers are lazy." But there are two kinds of lazy - stupid lazy and smart lazy. Smart lazy will do more work up front to remove work later on, stupid lazy will do less work up front but more work overall. I feel that the Gnome guys were stupid-lazy in the workspace/viewport matter - they removed a very useful feature to save themselves work up front, while making more work long term.
I've said it before, and I shall now say it again - I fear for the future of Free Software. I feel very much like a pilgrim who has come to a new land to escape religious persecution in the Old World, only to find that everybody in the New World is setting up to do the exact same thing! We get people fleeing Windows or Mac or.?, and the first thing they do when the arrive on our shores is start making things just like what they left.
This is addressed to all the posters who posted varients of "Why don't we just catch all the junk?"
Since you don't understand the problem, allow me to offer to help you understand it.
Come to my house. We'll go into the back yard, and I'll shoot at you with my AR-15. You catch the bullets. That's MUCH easier than catching orbital debris - the bullets are much larger (40 grains is roughly 2 grams) and MUCH slower (3600 feet per second is roughly 1 km/sec). Also, you will know ahead of time where the bullet will be - I'll make it easy and aim right at you.
Now, when you can catch those bullets, you can move up to orbital debris - much smaller, much faster, and moving on unknown trajectories.
"But we'll just use a big Kevlar net! We won't have to know where the bullets are heading!"
Fine. Here's your Kelvar net, about 1km on a side. It will only take about 1000 years to catch most of the debris, since "Space is big. Really really big. You can't believe just how mind-bogglingly huge space it".
To simulate the launch, let's go to Colorado Springs. I'll pay your way into Pike's Peak. Go to the top of Pike's Peak with the net - it's only a couple of tons. No, you cannot drive - you have to walk. I'll wait. That will help you understand the COST of putting your big net into space.
DON'T take what you see on Star Dreck as reality - space is HUGE, junk is SMALL. This is not a simple problem.
Ah. Best not get too nasty about SBC - I know one of their techs down there;)
I grew up in Ark City, and tried to get a job out at Strother Field. So I know a little bit about Winfield. Is the economy there getting as hammered as Ark City's?
Hey guys, see if you can get Gary to consent to an interview on/.
I know the question I would ask:
Given that "they" say computers own the opening and the endgame, while masters own the middle, what would you think of a match up of 2 chess programs and 2 grand masters (yourself being one) - with the computers to advise, but the master to make the final decision? Who would you want to play against (man and machine), and what program would you choose to be your assistant?
I have a friend in Belle Plain, and he have very little good to say about Sprint.
They won't deploy DSL, only their wireless service. Unfortunately, where he is he would need a 75 foot tower to have LOS to the transmitter.
Personally, I don't see a problem, but I'm a ham - the bigger the stick the better.
And as I said in my journal, Southern Kansas really does understand customer service - and their eyes don't glaze over when you use the "L" word.
And a friend of mine gets quite good service from Haviland Telephone Co, but that's hardly surprising - when he filled out his forms to get internet service from them, under Employer/Job Title he truthfully put down "Your Boss (ret.)"
OK, I was trying to be polite, but I see that was wasted.
You are full of shit.
Yes, in some areas the Baby Bells are the ILECs and own the wires.
However, there are plenty of areas in which the Bells NEVER owned the wires - in those places the ILEC is not, and never has been, a Baby Bell, a part of AT&T, or anything resembling it.
You mis-interpreted information covering part of the country (a large part to be sure, but a part, not the whole) to cover the whole company.
Since you haven't done ALL your homework, I suggest you do so.
Since you seem to be incapable of simple Googling, I will help you out.
Here I sit, in rural Kansas (the lot my house is on was a wheat field less than three years ago), typing this comment and downloading the SGI Freeware package for Irix over my DSL.
A DSL connection that has NOTHING AT ALL to do with a Baby Bell.
Believe it or not, SBC, but you are NOT the only game in town. The independant telcos are doing MUCH BETTER at deploying DSL than you are!
I thought it funny - last Friday, I came home to find a flyer on my door for DirectTV's sat based Internet service. I guess the poor schlub who came down from Wichita thought that we rubes in the country couldn't possibly have fast Internet service...
Thanks, I'll take my nice 50ms ping over a bird any day of the week.
Many of these reputation managers involve rating methods, from Epinions.com's Web of Trust, to eBay's ratings (and huge anti-fraud department), to Slashdot.org's highly-evolved Meta Moderation system.
DNS should be reversed...
on
U.S. Endorses ENUM
·
· Score: 4, Insightful
(NOTE: I realise what I am about to propose will never happen.)
The DNS system should be reversed - in other words, this site should be http://org.slashdot
Justification: The ideal would be for the domain to move from the least specific to the most specific. Consider the current system: First, you have the protocol - the most general part of the URL. Then, you have the domain, moving from the most specific to the most general. Then, you have the URI (directory and filename), which moves from the most general to the most specific.
Now, consider if DNS were to be reversed. You would move from the most general (the protocol), then the TLD, then the organization, then the machine, the directories, the file name, and any CGI args.
The ENUM system would be more in line with telephony - you would have the country code, then the area code, exchange, and finally number, just like the current system, rather than having to reverse the number.
You could still have the completion feature you have now - if you type tel://555.1212 the system could automatically apply the default country code and area code, it would just prepend rather than append.
(Oh, BTW: on ENUM, they should have allowed each logical grouping of the telephone to be one subdomain - in other words, county code.area code.exchange.number, rather than c.o.u.n.t.r.y.c.o.d.e etc.)
Slashdot Mirror
Yes, basically what you need is a tuner, a digitizer, and enough CPU to do the job. The last one can be the killer, though.
Here's how you can receive multiple signals at once with one tuner - let's pick on ordinary FM, and let's say I want to receive 95.1 MHz and 96.3 MHz.
The first requirement is that the two signals in question have to be reasonably close in strength - if one signal is coming in at -60 dBm (one millionth of a milliwatt) and the other at -120 dBm (one millionth of one millionth of a milliwatt) it's not going to work. But let's say both signals are coming in at -100 dBm, so there isn't a problem there.
OK, so what I do is make a receiver that will amplify all signals around 95.7 Mhz (half-way between the two) and downshift that to a convenient IF, say 10.7 MHz. Ideally, I'd want to bandwidth limit the signal to about 1.5 Mhz - that way I get both the signals I want, and not much else.
So my receiver is now outputting a signal at 0 dBm (1 milliwatt). If I look at that signal on my spectrum analzyer, I see 2 peaks - one at 10.1 MHz (the signal that used to be 95.1 Mhz), and one at 11.6 Mhz (the signal that used to be at 96.3 Mhz).
OK, now I digitize the signal. I need to sample at more than 3 Msample/sec (Nyquist's criterion) - any less and the two signals will be "folded" into one, and it's game over. To keep it simple, I will digitize the signal at 40 MSample/sec.
Now, I have a bitstream that contains the information for both signals. First, I multiply the signal by a mathematically generated cosine and sine wave at 10.1 MHz. This will give me two signals - I and Q. I is the "in phase" signal - the product of the cosine signal and the digitized signal. Q is the "quadrature" signal - it is 90 degrees, or a quarter circle out of phase with "in phase" signal (hence the name quadrature).
Next, I lowpass the signal - I run I and Q through a digital filter that removes all frequency components above 75 KHz.
Now, I compute a four-quadrant arctan() on the I and Q filters - this gives me the phase angle of the signal. I then differentiate that signal - subtract each sample from the previous sample. That gives me the instantanious frequency of the 95.1 MHz carrier - and there's your audio (if you want stereo I have to go trhough a few more steps....)
Now, I do the exact same thing, except this time I use a mathematically generated 11.6 MHz cosine/sine wave. The end result is the 96.3 MHz signal.
Now, as you can guess, that's a lot of math. Hoever, there are chips that do all of that for you. The Intersil 50216 I keep mentioning has 4 independant sections, each of which will do all of those steps, on a 40 MHz signal (or faster), in real time. If you do the math, the chip works out to about 5 to 10 billion operations a second, for 10 watts.
Chips like the 50216 are used by cellular folks - the idea is they grab the entire cellular band, digitize it, and the pull the calls out of the mix. You have only 1 drify, nasty analog receiver section, and hundreds of nice, stable digital sections.
There are a few problems with this approach, however:
1) The wider the receiver, the more noise it picks up. A receiver that is listening to 1 MHz of the spectrum picks up roughtly ten times as much noise as a receiver listening to 100 kHz of spectrum. That extra noise limits what you can tune in.
2) Strong signals in your receiver's bandwidth will prevent you from hearing weak signals - this is called "desense". It's one of the things that makes CDMA and TDMA cellular harder to do than dumb old AMPS - a phone near the tower has to be told to speak softly, so that the tower can hear distant phones.
3) Faster is harder - digitizing a 455 kHz IF is dirt cheap. Digitizing a 10.7 MHz IF is harder. Digitizing a 100 MHz IF to be able to cover the whole cell band is a bitch.
I wonder if my buddy at Spectrum Signal Processing is reading this thread - perhaps they might be able to release a slightly lower cost solution to this.
Or not.
Hey Meirowsky - You reading?
Actually, 20MHz isn't so bad - I work with 40 Msample/sec 12-bit flash converters, and there are 100 Msample/sec 12-bit flash converters on the market.
However, you DON'T build things like this with your brother's wood-burning kit and a old nail - These parts come in surface mount packages, and your board has to be carefully designed to maintain proper impedance matching on the RF traces, as well as having excellent grounding (RF and digital grounds meeting at one and only one point, ground planes cut as needed to prevent current loops, etc.).
Lastly, you need a proper dithering circuit to introduce noise equivelent to 1/2 of the least significant bit, in order to shape the quantization noise out of the frequencies of interest. Otherwise, you end up throwing away a couple of bits of resolution.
Those are the sorts of things you have top-notch RF designers laying out, and a top-notch fab build for you - either by having such a fab working for you, or by contracting it out.
Yes, things like a PCI core are DEFINITELY something you want to be able to use, not create!
That's where Gnu + hardware is a great thing - opencores and the like are GREAT ideas.
A few nitpicks:
.7 volts a 6 or a 5?), and you have to slice at the correct time (the symbols are only defined at certain times - any other time the signal isn't valid, it is a blend of the current and the (next|previous) symbol - what is called inter-symbol interference or ISI). So you have to do symbol tracking - figuring out when to sample, and at what levels to slice.
You don't get harmonics (frequencies that are related to the fundimental by an integer multiple), you get mixing products, also known as "sum and difference".
You get harmonics when you feed a single signal into a non-linear element - feed f1 in, get f1, 2*f1, 3*f1, 4*f1,... out. This is commonly used in tranmsitters to allow the use of a lower-frequency crystal to generate higher frequency carriers - you use a 10 MHz crystal, and the feed it into a non-linear element such as a squaring amp, and pick off the tenth harmonic to get 100 MHz.
Mixing involves feeding 2 signals f1 and f2 into a multiplier - you get f1, f2, f1-f2, and f1+f2 out. Mixing allows changing a frequency by a non-integer relationship. You have heard this used in the voice distorters used on TV to mask mob informants - they mix the person's voice with a low-frequency signal to change the pitch of the speaker's voice. This is also the basis of any modern superheterodyne receiver - you mix two different (heterogenous) signals together.
The idea is to take the signal from whatever frequency it is on, and move it to the frequency you have designed your circuit to work at - an "intermediate frequency", or IF. You then filter the signal, amplify it to a specified level, and repeat as necessary to get the signal where you want it. For example, a standard FM radio might go from the broadcast frequency to a 10.7 MHz first IF, then to a 455 kHz second IF, then finally to the FM detector circuit.
Eventually, in a design like GnuRadio, you sample the signal. The tricky bit is you have to sample at a frequency not less than twice the highest bandwidth in the signal (Nyquist's criterion). For a 6MHz wide TV signal, that means you need to sample at not less than 12 million samples per second.
Then, for a system like HDTV, you are dealing with a complex signal - and I mean complex as in sqrt(-1), not just as in "not simple" - you need both the real (in-phase, or I signal - the "real" part) and the quadrature (out-of-phase, or Q signal - the imaginary part). The signal is 8VSB - eight level vestigial sideband. So you have to do carrier recovery and tracking (because the carrier itself was removed - that is what makes it a sideband signal), then you have to convert the signals from the analog RF signal into one of 8 levels (slicing is the technical term). However, you have to slice accurately in 2 dimensions - you have to slice at the correct level (is
Finally, once you have a symbol stream, you then have to do all the foward error correction - you have to de-interleave the signal (think of unshuffling a deck of cards) - interleaving is done so that a transient interference (like a lightning strike) doesn't scramble adjacent bits - the errors are spread out.
Then you do your block error correction - this can undo a small number of bit errors per block (again, that's why you interleave the signal: so that block error correction needs to only correct a few bit errors per block).
Then you do some more protocol recovery, and you have an MPEG stream.
Normally, you do this sort of stuff with a big FPGA or an ASIC. The GnuRadio folks are doing it in software. The up side is that you can more easily tweak the code. The downside is that you are not going to be real-time for a few more iterations of Moore's "Law".
What gets to be REALLY fun is when, in addition to all of the above, you have to compute parametrics on the signal - not just recover the bits, but measure how far out of ideal the signal was (that's the sort of stuff I do for a living.) When you do that, you have to do all of the above, THEN once you have an error corrected bit stream you have to regenerate an ideal signal and compare the received signal against it, and measure how far away from the ideal signal the real signal is.
And THAT is when you start using multi-GHz processors, 10 million gate FPGAs, big-ass DSPs, and all sorts of other fun stuff.
Well, I DO do this stuff for a living, as well as being a computer geek and a ham.
But really, $1300 for the digitizer card is a bit steep - I work with a system using a 40 MSamp/sec 12 bit flash converter and Intersil 50214. The Intersil is about $30, and I don't think the flash converter is much more. Add a $50 FPGA to do the interfacing to the PCI bus, and you could do scatter-gather busmastering capture to the main system pretty easily.
Use a $50 Intersil 50216, and you could do most of the heavy lifting with it - Final IF filtering, I/Q recovery, post-detection filtering, symbol tracking, etc. That would remove a lot of the CPU load from the system, possibly allowing for real-time aquisition and decode.
Go to one of the board fab houses, and you could probably get a board built for about $500, maybe less.
Considering that people are spending $500 for video cards, this might not be so bad.
Man, I wish the Gnu folks would build their own hardware card rather than the card they are currently using - it's quite expensive.
I'd love to see them put a decent FPGA, an Intersil 50216 4 channel digital downconverter, and a nice 60 Msample/sec 12 bit flash A/D converter on the card - they could do that for a bill of materials of about US$200, and have enough power to do the capture properly.
Before you say "Fine - why don't YOU design it?": I'd love to get more involved in GnuRadio, but I'm afraid of potential conflicts of interest both ways - contaminating GnuRadio with my professional work and possibly exposing my employer to problems with GPL infringment.
Also, is anybody big in the Gnu Radio project going to be at IWCE (International Wireless Convenention and Exposition) March 10 - 14? If so, where? I'm getting in on an exhibitor's badge - maybe I could get pictures?
(I was 12 in 1977)
1) Start learning Tae Kwon Do - it's a better fit than Karate.
2) As soon as you are old enough, buy lots of AR-15's and street sweepers. Hold them until the Democrats get into power. Sell for big profit.
3) Save as much money as you can - on your first job, put all your overtime pay into investments (see #2, above).
4) Don't do business with United Engines Specialists in Wichita - they don't understand how to connect an oil pump.
5) Get Mom to stop smoking. Failing that, after her first bought with cancer, insist she be checked every six months by a competent oncologist.
6) Don't go to the hospital in Ark City (see #5).
7) Learn Z80 assembly, write a BASIC interpreter, release it to all who wish to use it, with the proviso that they have to give others the same distribution rights you gave them.
OK, so somebody explain why ATA disks can be tested in batches and SCSI cannot. This still sounds like smoke and mirrors to justify raping SCSI users.
(see my rant about this very thing.)
.?, and the first thing they do when the arrive on our shores is start making things just like what they left.
First, viewport vs. workspaces - the arguement was that since workspaces and viewports "did the same thing" (let you have more deskspace than desktop) there was a redundancy. So, the Gnome team eliminated one. I feel they eliminated the wrong one.
I've tried running Sawfish, and it crashes horribly. This makes getting my beloved viewports back somewhat more difficult.
"People don't hate computers, they hate lazy programmers." The problem is that it is far easier to remove features than to properly manage them so that newbies have what they need, and power users have what they want.
"Good programmers are lazy." But there are two kinds of lazy - stupid lazy and smart lazy. Smart lazy will do more work up front to remove work later on, stupid lazy will do less work up front but more work overall. I feel that the Gnome guys were stupid-lazy in the workspace/viewport matter - they removed a very useful feature to save themselves work up front, while making more work long term.
I've said it before, and I shall now say it again - I fear for the future of Free Software. I feel very much like a pilgrim who has come to a new land to escape religious persecution in the Old World, only to find that everybody in the New World is setting up to do the exact same thing! We get people fleeing Windows or Mac or
This is addressed to all the posters who posted varients of "Why don't we just catch all the junk?"
Since you don't understand the problem, allow me to offer to help you understand it.
Come to my house. We'll go into the back yard, and I'll shoot at you with my AR-15. You catch the bullets. That's MUCH easier than catching orbital debris - the bullets are much larger (40 grains is roughly 2 grams) and MUCH slower (3600 feet per second is roughly 1 km/sec). Also, you will know ahead of time where the bullet will be - I'll make it easy and aim right at you.
Now, when you can catch those bullets, you can move up to orbital debris - much smaller, much faster, and moving on unknown trajectories.
"But we'll just use a big Kevlar net! We won't have to know where the bullets are heading!"
Fine. Here's your Kelvar net, about 1km on a side. It will only take about 1000 years to catch most of the debris, since "Space is big. Really really big. You can't believe just how mind-bogglingly huge space it".
To simulate the launch, let's go to Colorado Springs. I'll pay your way into Pike's Peak. Go to the top of Pike's Peak with the net - it's only a couple of tons. No, you cannot drive - you have to walk. I'll wait. That will help you understand the COST of putting your big net into space.
DON'T take what you see on Star Dreck as reality - space is HUGE, junk is SMALL. This is not a simple problem.
You mean, "...that's the EMACS macro
FSV a FSN port for Linux and *BSD based systems.
You'd better have OpenGL running hardware accelerated, but it does work.
How close are you to getting your degree? Depending upon the kind of work you do, you might want to throw a resumee our way.
DSP, RF, networking, Linux. Fun stuff.
Ah. Best not get too nasty about SBC - I know one of their techs down there ;)
I grew up in Ark City, and tried to get a job out at Strother Field. So I know a little bit about Winfield. Is the economy there getting as hammered as Ark City's?
Hey guys, see if you can get Gary to consent to an interview on /.
I know the question I would ask:
Given that "they" say computers own the opening and the endgame, while masters own the middle, what would you think of a match up of 2 chess programs and 2 grand masters (yourself being one) - with the computers to advise, but the master to make the final decision? Who would you want to play against (man and machine), and what program would you choose to be your assistant?
LinuxOnHal - which town are you in?
I'm in Viola, KS.
I have a friend in Belle Plain, and he have very little good to say about Sprint.
They won't deploy DSL, only their wireless service. Unfortunately, where he is he would need a 75 foot tower to have LOS to the transmitter.
Personally, I don't see a problem, but I'm a ham - the bigger the stick the better.
And as I said in my journal, Southern Kansas really does understand customer service - and their eyes don't glaze over when you use the "L" word.
And a friend of mine gets quite good service from Haviland Telephone Co, but that's hardly surprising - when he filled out his forms to get internet service from them, under Employer/Job Title he truthfully put down "Your Boss (ret.)"
OK, I was trying to be polite, but I see that was wasted.
& q= independent+telephone+companies
You are full of shit.
Yes, in some areas the Baby Bells are the ILECs and own the wires.
However, there are plenty of areas in which the Bells NEVER owned the wires - in those places the ILEC is not, and never has been, a Baby Bell, a part of AT&T, or anything resembling it.
You mis-interpreted information covering part of the country (a large part to be sure, but a part, not the whole) to cover the whole company.
Since you haven't done ALL your homework, I suggest you do so.
Since you seem to be incapable of simple Googling, I will help you out.
http://www.google.com/search?hl=en&lr=&ie=UTF-8
Now, remove your cranium from your rectum, read the links, and learn.
I'm sorry sir, but you have no clue what you are talking about.
There are plenty of independant phone companies out there, and they DO own the wire.
There is no "law" in the US to the contrary.
I would suggest you go recheck your sources.
You see, MY sources are actual OWNERS of the telephone company. So I think they know just a bit more about the subject than you do.
Here I sit, in rural Kansas (the lot my house is on was a wheat field less than three years ago), typing this comment and downloading the SGI Freeware package for Irix over my DSL.
A DSL connection that has NOTHING AT ALL to do with a Baby Bell.
Believe it or not, SBC, but you are NOT the only game in town. The independant telcos are doing MUCH BETTER at deploying DSL than you are!
I thought it funny - last Friday, I came home to find a flyer on my door for DirectTV's sat based Internet service. I guess the poor schlub who came down from Wichita thought that we rubes in the country couldn't possibly have fast Internet service...
Thanks, I'll take my nice 50ms ping over a bird any day of the week.
Ahem.
Obviously, this is some quaint usage of the term "highly evolved" of which I was previously unaware.
Symantec.
The same Symantec who's Norton Anti-virus product is prominently featured in a rash of spams in my inbox?
The same Symantec who claims to follow up on reports of this to spamwatch@symantec.com? That never seems to lead to any sort of actions?
The same Symantec who just changed their auto-renewal to cost people more money IN THE MIDDLE OF THE RENEWAL CYCLE?
Huh, who'd'a thunk it?
Glad I use somebody else's anit-virus software.
(NOTE: I realise what I am about to propose will never happen.)
The DNS system should be reversed - in other words, this site should be http://org.slashdot
Justification: The ideal would be for the domain to move from the least specific to the most specific. Consider the current system: First, you have the protocol - the most general part of the URL. Then, you have the domain, moving from the most specific to the most general. Then, you have the URI (directory and filename), which moves from the most general to the most specific.
Now, consider if DNS were to be reversed. You would move from the most general (the protocol), then the TLD, then the organization, then the machine, the directories, the file name, and any CGI args.
The ENUM system would be more in line with telephony - you would have the country code, then the area code, exchange, and finally number, just like the current system, rather than having to reverse the number.
You could still have the completion feature you have now - if you type tel://555.1212 the system could automatically apply the default country code and area code, it would just prepend rather than append.
(Oh, BTW: on ENUM, they should have allowed each logical grouping of the telephone to be one subdomain - in other words, county code.area code.exchange.number, rather than c.o.u.n.t.r.y.c.o.d.e etc.)
speak.not.his.name - Cthulhu fan site
whats.your.name - Lynyrd Skynyrd fansite.
bingo.was.his.name - Oh!
Don't mod me past three!
Come up with your own - it's fun!