Re: [Flexradio] [KB] FLEX-5000 FAQ has been updated (important)
Jim Lux wrote: At 05:49 PM 4/23/2007, Bob Maser wrote: FWIW, the C and D versions will be twice as large as FT-2000D and 1.3 times as large as a IC-7800. I wonder how much these big dudes are going to weigh, I'm guessing around 35 lbs unless a switching power supply is used, hope not. There's no good reason not to use a switching supply these days, assuming you carefully specify/design/choose your supply. Sure, you can't use a $30 unbranded whitebox PC supply, but it's certainly possible to use switching power supplies in high performance RF equipment. (e.g. the radio science receivers on deep space probes use DC/DC converters, and they are insanely sensitive to interference, most high end lab equipment uses switchers, if only to run the ubiquitous PC motherboard in the instrument) With a good switcher you can get very much better regulation, almost total insensitivity to line voltage variation, a lot less heat dissipated in the enclosure, and better transient response. Of course, switching power supplies are like chainsaws.. powerful for evil as well as good. I've been using a lot of off the shelf DC/DC bricks recently and found most of them very quiet. It *is* something that cannot be done casually, though. Jim, W6RMK Switched power supplies vary a lot with regards to RF emissions. I replaced one that came with a case with an expensive 70UKP PSU and it outputs no detectable RF noise at all. When listing to the radio, one cannot tell if the computer is on or off based on the RF receiving. In case people are wondering, the PSU I use is made by TAGAN. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ FlexRadio Homepage: http://www.flex-radio.com/
Re: [Flexradio] Higher sampling rates yeilds improved sensitivity?
Joe - AB1DO wrote: Dan, just out of curiosity I performed the following experiment: Using PowerSDR1.9.0 SVN821 Scound card is a Delta-44 Disconnected the Delta-44 cable at the break-out box, thus disconnecting the hardware Preamp set to Med Measured the noise floor in a 500Hz filter. To stabilize the digital signal meter, I set it to average over a period of 3 seconds. Result: At a sample rate of 48kB/s, the noise floor measured -130.5dBm At a sample rate of 96kB/s the noise floor measured -132.5dBm That would indicate an improvement of around 2dB in sensitivity, though not quite the 3dB you predicted. I cannot test 192kB/s (yet). Hope this helps, 73 de Joe - AB1DO You might not be measuring what you think you are measuring. The results you get are a result of the fft algorithm. The fft algorithm indicates power present in each bin. At 48kHz, lets say you get noise power in the 500Hz bin with 10 units of noise (bogus scale just to demonstrate a point) At 96kHz, this bin gets broken into 2. One of these bins will have the 500Hz signal, the other will not. So, on average, the 500Hz bin will now have 5 units of noise, with the other 5 units in the next door bin. One therefore has the apparent reduction in noise at 96kHz over 48kHz. As the sample rate increases, each bin has a narrower bandwidth. Oversampling does improve the result a bit, but one gets diminishing returns, so 60Mbits/s sampling at 16bit, is unlikely to give 26bit accurate samples at 48Khz. One does not spontaneously improve the dynamic range of the front end just by oversampling. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Linux, any chance of a knoppix like setup?
Jim Lux wrote: At 02:58 PM 1/1/2007, Ken N9VV wrote: I enjoyed this thought provoking article about the real cost of M$ Virus (Vista) http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.txt de ken snip And that gets to what the future of an SDR1000/PowerSDR is... is an SDR1000 a hacker platform? is it a consumer software radio? I think the answer is both. It works very nicely as a consumer radio, but also is open enough to act as a hacker platform. If the latter, then PowerSDR must go the Vista route (unless MS goes must is way to strong here. PowerSDR does not have to go any particular route. It is an open platform and will just go whichever way users want it to go. out of business or becomes a 10% minority share player in the market). There are already limitations imposed on PowerSDR (as shipped) to meet regulatory requirements, and any peculiar DRM related functional issues would be the same. Hey, the source code can still be open and so can the hardware interface specifications, so the philosophical intent of Gerald, et al, can still be met. Regulations are different in each country. The PowerSDR source code ships to be compatible with US Regulations, but users in other countries are free to modify the source code they use in any way they see fit and lawful. For example, the UK authority is not nearly as draconian as the FCC. As far as the former goes, there's a small and vibrant community of people playing with the SDR1000 hardware platform in a variety of ways. And I think it will stay that way. But recognize that the software/hardware hacker and tinkerer is a distinct minority of the total SDR1000/PowerSDR market. There are a lot of people who would be perfectly happy with a SDR1000 in a sealed (no user serviceable parts inside) box connected to a sealed Windows Genuine Advantage (No user serviceable software inside) Vista box, as long as the box works. The SDR1000 is most certainly not a no user serviceable parts inside product. ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] [hpsdr] D anyone?
Naylor Jonathan wrote: * High Performance Software Defined Radio Discussion List * Hi All You don't need to use esoteric languages to get cross platform capability. The use of C++ and careful use of cross-platform libraries can make for a very pleasent development environment and porting is often a one-time job taking a few minutes. The software for UWSDR is written that way and runs on Linux, Windows and Mac OS X already. The number of platform dependent #ifdef's is small. Jonathan ON/G4KLX I agree. Keep is simple. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Linux, any chance of a knoppix like setup?
Jim Lux wrote: Sure. BUT PowerSDR is a product from a company that presumably wishes to stay in business and has to sell product to do so (unless Gerald is going to altruistically support ham radio into the future..). And for the next few years at least (and probably well into the next decade) the dominant platform (in terms of percentage of computers) is going to be windows (just out of inertia, and because MS can spend a gargantuan sum of money to keep it that way). Out of the hundreds,if not thousands, of SDR1000 owners, I suspect a very small percentage participate on this list, and there are a huge number of people just appreciating the SDR1000/PowerSDR combination as a high performance black box appliance. And, statistically, those people are more likely to be running Windows. I don't believe Flex-radio sell the PowerSDR at all. It is open source and GPL. Flex-radio sell the Flexradio HARDWARE, and use PowerSDR as a tool to do that. The better PowerSDR is, the more Flexradio HARDWARE they will sell. They let other people in the open source community improve the software with them and that results in better, more reliable software, and therefore more Flexradio hardware sales. The vocal minority, interested in tinkering, etc., for whom open source is a godsend, probably has a higher percentage of Linux users. Further, just because they're willing to tinker, they're also willing to suffer some amount of pain to shift from Windows to Linux (and, yes, there is significant pain in doing so, notwithstanding how congenial the environment is after the changeover). I don't believe there is significant pain to shift from Windows to Linux. Microsoft might want users to think that, but it really is not true. The SDR1000 is most certainly not a no user serviceable parts inside product. The fact that it is user servicing allowed and encouraged but supports the black box model is all to the better. That is more the point I was trying to make. Jim, W6RMK ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Linux, any chance of a knoppix like setup?
Jim Lux wrote: I call BS. It is a royal pain just to reinstall your existing applications on a new computer, staying in the Windows world. There are lots and lots of Windows only applications out there that are quite useful, if not necessary. For instance, I use 4NEC2 as a front end for NEC analysis. It's not available for Linux, and I'm not particularly eager to go back to writing and reading bare NEC decks. Works fine here in Linux using a tool called wine. It lets you use your must have windows applications under linux, until a better alternative presents inself. I use Microsoft Word's equation editor, reviewing, and cross referencing capabilities a lot, and open office is incompatible for some reason. I haven't dug into why, but since I need to generate MS Word documents for others to review and work on, I'm not likely to change, nor am I interested in spending lots of time figuring out how to make it compatible. I have no idea on this one, so you might have a point here. What about hot-syncing my Treo with my PC? Works fine. Using a bluetooth radio link to do the sync. What about support for my Tablet PC? I'd hate to give up my stylus and the ability to take notes on a tablet. Works fine in Linux. Linux support touch screens and the like. Then, there's those horrible, but necessary, websites that are IE only. All too many manufacturers of components put their data out with slick IE only web interfaces. Why, I do not know (just ignorance on their part, or they hire a low budget web developer who is MS centric). This may or may not be true. I have just never found such a site yet. What about compatiblity with my co-workers? I work somewhere where we have a variety of OSes (Win, Mac, Linux, Solaris, etc.) and people that are non-Windows users tend to wind up having a Windows machine too, just to interoperate. (This just moves the pain of interoperation to just one person, rather than inflicting it on many people) The occasional incompatibility between Powerpoint on the Mac and Powerpoint on the PC alone is a pain, and they're both MS products. There are incompatibilities between MS Office 2000 and MS Office 2003 both on the Windows platform, so you cannot really use this complaint against Linux. So, if you are running in your own isolated world, you can probably find functional equivalents for most applications that are Linux compatible, and your work can go along just as well or better. However, many people are in a Windows environment at work, and would just as soon use the same applications at home as at work, especially if their life isn't wrapped up in computers and they derive no special thrill from being multi-OS-lingual. So, I call BS on the claim of no significant pain to move from Windows to Linux. It just ain't so, which means that if you want people to move, you have to provide not only comparable functionality, but also make the move to Linux (and back to Windows) relatively painless. It's the move back that is especially important, because you may find that Linux just isn't going to work for you. You clearly have your view, and I have mine, I guess we can call this quits and end this thread. :-) Jim, W6RMK ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Vista / XP / Linux
Ken N9VV wrote: My first encounter with Linux was very disappointing. I could not get WiFi links to my router to work (making it virtually impossible to update Ubuntu). Then my PCI card for USB was not recognized. Finally I could not find a utility that would show me when webpages were updated (such as WebSiteWatcher for Windoze). I guess I will just have to give up some favorites in order to achieve some peace of mind :-) de ken Linux is really not that difficult to get to know now. Especially with distros like Ubuntu where real money is being spent to make them easier to use on the desktop. All people need to understand is that Linux is not Windows. A move from Windows to Linux is about the same difficulty as moving from Windows to Apple Mac OS X. Once one finds out where things are, they are both easy to use. WiFi links are still difficult. For example, my laptop wifi just fails most of the time in Windows, but using the Linux madwifi drivers works reliably every time. It very much depends on the Wifi chipset being used. If it is a very popular one, it will work well in Linux, if it is a rare one, drivers might not yet exist or one might have to use the ndiswrapper drivers. A bit of googling should get your Wifi working in Linux. You must have a very old motherboard without a motherboard based USB port already on it. Why do you need the PCI USB card? For installing software on ubuntu, one just runs a program called synaptic from the System-Administration menu. Other Linux distros use similar tools generally called package managers. One simply gets a list of all software that can be installed on Linux and one simply ticks the ones one wants. No going to web site X and downloading and then installing like in windows. There is just one place for all applications. For special cases where the software is not on the synaptic list, one can use a number of alternative methods to get the software one needs. It would be very easy to get FlexRadio to appear in the synaptic list of applications. So, in conclusion, when Linux is used on mainstream hardware with mainstream applications, it is very easy to use, but once one tries to use applications that are not so common, some more detailed knowledge of Linux is sometimes required. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] [OT] A must read A Cost Analysis of Windows Vista Content Protection
KE5EUP wrote: Here is a link to the original post: http://it.slashdot.org/article.pl?sid=06/12/22/1727245from=rss and here is the document: A Cost Analysis of Windows Vista Content Protection === Peter Gutmann, [EMAIL PROTECTED] http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.txt Last updated 22 December 2006 Well, Microsoft has just gone too far this time. It is yet more reasons to install Linux. Linux is doing well enough at the moment, without help from Microsoft! I am sure that the users will just purchase EDVDs (China's HD DVD format) instead. It is free of IP and will suit open source very well. In open source, the only features that get implemented are the ones user's want, so I don't think open source will get round to implementing content protection features similar to Microsoft Vista because users don't want it. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] [hpsdr] PS3 support in Linux 2.6 - Cool!
It is not surprising really. The cell processor was developed and tested using Linux. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] FlexRadio and Apple Computers
Ove Rønning wrote: Hi everyone. I’ve already made a similar posting in one of the FlexRadio forums, but perhaps this is a better place for it. I’m very fond of Apple computers, but to run PowerSDR one needs Windows. With the Intel based Macs of today Windows isn’t a problem using either the Bootcamp or the Parallels software. I’d like to use a MacBook laptop for my FlexRadio setup. Is anyone using an Apple computer together with the SDR-1000 and PowerSDR? If so, what kind of computer and are you using Bootcamp or Parallels? Ove Ove, It might be better to try and port the Linux dttsp code over to the Apple. I think it is easier to port code from Linux to Apple, than it is for Windows to Apple. I think jackd has already been ported to Apple, so hopefully it will not be too much of a problem. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Best Sound Card For Sensitivity Only
Alberto I2PHD wrote: Give a look at this : http://www.emu.com/products/product.asp?category=505subcategory=491product=13552 The specs are outstanding... 73 Alberto I2PHD --- Andy Smith wrote: Hi Folks, Can someone please tell me which soundcard specs to look at that will give the ultimate in SDR sensitivity (not just for the SDR1000), I presume the number of bits and dynamic range make a difference but I am looking for the ultimate (ideally USB or Firewire) sound card for sensitivity only, can the FA-66 be bettered for sensitivity alone? Thanks, Andy. Just FYI. I am writing a Linux ALSA driver for the emu cards at the moment. emu1212m and 1820m currently work. Still waiting for a hardware sample for the emu1616m from emu. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] What PC?
Alan NV8A wrote: I think you mean PCI Express. PCI-X, despite the confusing similarity of names, is something else. BTW, although we are accustomed to speak of CPU speeds (e.g., 2,8GHz), both Intel and AMD are just using meaningless model numbers. E.g., my AMD dual-core CPU is called a 3800+, but the clock speed is actually only 2.0GHz. Anybody who goes looking for a new machine needs to figure out the actual speed. 73 Alan NV8A AMD use it's model numbers so that you can compare CPUs in their range. The clock speed actually has very little to do with how quickly the CPU can execute instructions, so the AMD model numbers are actually a better judge than the clock speed. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Vsound Update
Tim Ellison wrote: OK, folks. Listen up. I have the 411 on Vsound. First off, a bit of patience is in order. Rome wasn't built in a day. Neither will Vsound I had a chance to exchange a few e-mails with Phil regarding the current state of Vsound development. Just because you have not heard anything or seen a blog entry doesn't mean that nothing is going on. A lot is. Here IS what is going on. The delay getting a driver released is partly due to the rapid development of HPSDR (of which Janus will be of great interest to all SDR-1000 users) and mostly to do with our fine friends in Redmond Washington - Microsoft. The problem is Vista and the new low latency sound subsystem that runs in user mode; WDF (Windows Driver Foundation) of which some of it is supported under XP. The challenge is to be able to develop a universal user mode driver that will work with both Vista and XP. This effort is important for several reasons. One is that from a support standpoint, it is best to support one release. Second is that it would provide a low latency sound subsystem for BOTH XP and Vista similar to what jack does in Linux. If he takes the easy way out and makes an XP only version, there will not be any guarantees that it will work with Vista or be updated in the future to do so. I think it is a prudent decision to take the path he has been trying to be ready for Vista since it is so close to being released. Here is the rub. Since Vista is still in beta and features and technologies are stabilizing; WDF is still a moving target. Phil has told me that he had some initial success with his first cut at a functional user mode driver, but the next beta release of Vista broke it. He is try to find out what changed and why. To that end, Phil has been in direct touch with one of the WDF developers in Redmond and other developers going through the same pains as he is. Microsoft is FAMOUS for poorly documenting their technologies. WDF is no exception. For more info on WDF you can check out this PowerPoint presentation. http://download.microsoft.com/download/f/0/5/f05a42ce-575b-4c60-82d6-208 d3754b2d6/UMDF_Intro.ppt Now, for those that paid their $$ to begin this development effort, you are to be commended for you contribution and foresight, but you have to look at this process like an investment. You paid for development not a finished product. A finished product will be the successful result of development. If you were expecting a quick ROI, then your expectations need to be modified a little bit. What you have to remember is that this risk free investment WILL pay off. The Vsound development process isn't like what Eric does by spoiling us with 2-4 upgrades a week. If it wasn't for SVN, our last upgrade would have been back on 23-June-06 Some of us know Phil personally and professionally and others know him by his immense contributions to SDR and the SDR-1000. He is an upstanding and honest person of the highest caliber and I have no reason to doubt that there will not be a Vsound in the coming months and it will knock the socks off of VAC for what we Flexers want to do with it. Others on the reflector can vouch for his character as well. Now, not everybody is going to agree with waiting a bit longer for Vsound to be done right. That is your right. But I ask that if you feel that you have to express your comments regarding the pace of development, that you do not use a public forum such as the reflector for that purpose. That should be taken up directly with Phil in a private correspondence in a professional manner. Like how we all want to be treated. Thanks Phil for providing me with a detailed update on Vsound and allowing me to share it with the SDR-1000 community. The best of luck to you battling the mighty monster in Washington. -Tim Do you need any help with a Linux driver. I am an ALSA developer. Maybe we could get the HPSDR working in Linux earlier? James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Tonight's Teamspeak audio
Bill Tracey wrote: Tonight's audio from Teamspeak is posted at: http://www.tracey.org/wjt/temp/ts915.mp3 Cheers, Bill Listening to this, I heard 1hour 5 mins into the recording a conversation regarding filling fifos to send data onto the USB bus. The conversation centered around alternating send and receive sample. USB does not work like that. USB transfers blocks at a time, and is a half duplex interface. So, the TX fifo should be filled by X bytes (whatever the USB profile is set to), and then read the RX fifo read till fifo empty again. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] synchronization of multiple audio streams/radios
Jim Lux wrote: Something to contemplate for future incarnations is the ability to synchronize the audio streams (I/Q and/or baseband) from multiple radios, preferably on separate computers, but even on the same computer. If one wants to do interesting things requiring coherent processing, like diversity combining or phased arrays, you need to be able to match up the received signal from one antenna/radio with others. The reason I point this out is that a friend mentioned to me that while there are lots of flexible audio support packages out there (PortAudio, Jack, ALSA, etc.) not all of them offer the ability to synchronize to an accuracy of one sample. In general, systems designed for multimedia (where you have to sync to video frames) are more likely to provide this, at least to milliseconds, although he was unsure if they were good to microseconds (i.e. 1 sample time at 96 ksps is about 10 microseconds). There are, of course, issues when the sample streams have slightly different underlying rates (as, for instance, if you are combining streams from two different audio interfaces), but that's a lesser problem than just making sure the buffers are lined up (or that they have a fixed and knowable offset). Or maybe this is something totally out of scope for PowerSDR and it's descendants.. Jim, W6RMK On Linux and ALSA one can time stamp the audio down to sample accuracy. I am not sure if Jack supports providing this information to the application. The method to do this is quite simple. The sound card hardware tells the driver which sample the ADC and DACs are currently playing from. The application does gettimeofday() to get the current timestamp. The application then calls snd_pcm_delay() to retrieve the amount of samples between the ADC and the next sample to be read from the sound card hardware buffer. One can then interpolate to find out when the next read sample was actually sampled. One then reads the sample from the buffer. sample_accurate_time = current_time - (delay * samples_rate); Now, combine this with all receiving PCs using NTP to keep their clocks accurate, one is left with multiple recorded signals that are very close to being in sync. The recorded streams would probably need minor resampling as the gettimeofday() system call does not use the same clock as the sound card. This resampling could be done at either the source or destination PC. It would probably be best to delay the resampling to the destination PC. Some processing at the destination PC may be required to correct for minor timing differences between PCs, but this should be fairly easy as the limits on the amount of correction needed would be quite small. The improvement to this would be the possibility of using GPS timing sources. Now, if the PC gettimeofday() was synced to GPS timing sources, and also the clocking on the sound card. One would achieve extremely good sync between widely distributed PCs. Special care would be needed with the clocking on the sound card, because a frequency divider would be needed, and the signal after the divider would have to be in sync with all the PCs. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Console Graphics - maybe mode-specific?
Frank Brickle wrote: FWIW, the DttSP radio kernel is being developed and implemented in erlang. Barring unforeseen potholes, erlang will be the platform for the virtual radio. Why was erlang choosen? The FAQ at www.erlang.org states: Start quote 1.4. What sort of problems is Erlang not particularly suitable for? People use Erlang for all sorts of surprising things, for instance to communicate with X11 at the protocol level, but, there are some common situations where Erlang is not likely to be the language of choice. The most common class of 'less suitable' problems is characterised by performance being a prime requirement and constant-factors having a large effect on performance. Typical examples are image processing, signal processing, sorting large volumes of data and low-level protocol termination. Another class of problem is characterised by a wide interface to existing C code. A typical example is implementing operating system device drivers. Most (all?) large systems developed using Erlang make heavy use of C for low-level code, leaving Erlang to manage the parts which tend to be complex in other languages, like controlling systems spread across several machines and implementing complex protocol logic. End Quote So, a typical reason for NOT using erlang is signal processing. Why is dttsp therefore using erlang? James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Hardware for Linux
Scott Gordon wrote: All they talk here recently about hardware needed for dedicated SDR machine running windoze. What kind of hardware are some of you running for Linux/Ubuntu? I have not check Flex site to see if they recommend anything different. I am thinking about putting together another machine and begin to learn Linux thinking down the road it may be a good fit for the SDR? What I am looking for doesn't have to be the minimum but a mid-range pc. Will keep reading some of the earlier post here and see where some of you are at with the SDR on Ubuntu. Thanks Scott KQ8RP http://www.kq8rp.us The specs for a Linux machine are probably about the same as a windows machine. A Linux machine will probably run a bit faster due to not having to run virus scanners etc. Just check that the Motherboard chipset and any add it cards have Linux drivers. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] [OT] test your Microsoft Vista readiness
Alberto I2PHD wrote: KD5NWA wrote: I've also worked on getting the Linux versions on Delphi and CBuilder so they work on the modern Linux Kernels. That is almost complete, I can create visual applications in the IDE, compile them and they will run correctly, the only problem right now is the debugger, it will not run and hangs up. I need to work on it, I feel there is the possibility of a fix in sight, I've just been busy lately but I will have some time available soon. An alternative would be an external debugger. snip That's very interesting...please Cecil keep me posted on your progresses in having C++Builder (or Kylix if you prefer) running under Ubuntu. I am afraid I would have to kiss goodbye all the VCL components I harvested, modified and/or wrote during the last years, but one can always start afresh on the new platform... thanks. 73 Alberto I2PHD I am not sure what exactly you are looking for, but eclipse is a good multi platform development environment for java, C++ and C. Is C++Builder mainly a Windows tool? James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Has anyone seen this CW Transmit problem?
Jeff Anderson wrote: Hi James, At this QTH the problem is definitely at the computer output and *not* at the SDR1K itself. So, the problem is now narrowed down a bit. The problem is now computer hardware or software. So, what spec machine are you using, CPU (hyperthreading, multicore enabled y/n etc.), MEM, HD, Sound card Which software, Flex version, OS version, patches installed etc. One might be able to narrow down the problem if enough people respond. As only a few people apparently see the problem, I would suspect the sound card. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Has anyone seen this CW Transmit problem?
Jeff Anderson wrote: Hi Lee, Very interesting! I haven't been checking my power, so I just tried the following experiment: 1. Using an Autek WM-1 meter (in Peak Mode), set my SDR1K power to 10 watts when read on this meter. 2. Transmit CW: observe RF envelope on an external oscilloscope and Power on wattmeter. Results: Normal Operation: Envelope is clean, and power on wattmeter is 10 watts. Screwy Operation: Envelope appears to have modulation (as seen on scope), and power on wattmeter can be anywhere from, say, 12 to 17 watts (depending upon the apparent depth of the modulation on the signal). (Note: SDR1K Fwd Power also shows a higher reading (15 watts in lieu of the normal 10 watts). So - I'd say there's a good chance you and I are experiencing similar problems. Another strange thing that I've noticed is that, when this problem occurs, there is a slight change in how I perceive the Transmit CW note from my SDR1K speakers - it almost seems as though the note has shifted position spatially. Weird, eh? - Jeff, K6JCA Lee A Crocker [EMAIL PROTECTED] wrote: I have been fighting this problem for several months. The problem started after 1.4.16. Prior to this release the situation was rock solid. I get precisely what you describe. Also my power output advances significantly from a nominal 100w to 135w when I get the modulation. The situation seems to be random and occurs about 10-20% of the time. It will on occasion correct itself during a transmission, or it will go into modulation mode during a transmission. Before it does that I can hear a crackle on the signal. It sometimes has variable penetrance, meaning instead of 135W it may only be 110 or 120 and the modulated portion of the signal is audiably less. I use a P4 3.3ghz with a firebox. I have 2 identical SDR systems including computer and firebox and it happens on both systems. Also I have been told this problem has not occurred at flex headquarters so I am glad to see it is not peculiar to my system. 73 Lee W9OY Has anyone been able to narrow down the problem to the computer soundcard output, or is something going wrong inside the SDR1000 hardware. This problem could be happening in the computer software or the sound card hardware, but identifying which part is wrong would be helpful. There have been cases of some sound card hardware causing the left and right channel to be one sample out of sync. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Cw Latency Problem Solved?
Frank Brickle wrote: If you want to monitor anything passing through the audio subsystem -- note, some sound cards provide a hard bypass, but that's looping around the subsystem -- you can't ever get around a minimum of 1 buffer latency. 256 sample buffers / 192000 samples per sec = 1.3 ms latency. There will probably always be a way to patch signal around the audio subsystem so as to eliminate latency entirely. If you want to monitor what the audio subsystem and signal processing are doing, however, then some latency is always going to be there. You could provide a secondary digital path through the host computer that used, say, 64 sample buffers. 300 usec isn't bad. But you don't want to use those same 64 sample buffers for your filters, probably. So with minimum latency you won't be actually monitoring the processing, just your input. FireWire systems can likely get the absolute minimum down to around 10 samples. They still won't have passed through the processing in that case either, however. As long as the audio systems use buffered IO, the latency will never be completely eliminated. As long as you use FFT-based convolution for efficient filtering, the true latency will never be less than the length of the primary filters. 73 Frank AB2KT Most sound PCI sound cards use a PCI transaction to transfer a block of bytes across the PCI bus. On most sound cards this is 64bytes. So, with 16bit stereo output, this equals 16 samples per PCI transaction. The sensible values for an application to use are some multiple of 64bytes for the chunk/period of the entire audio buffer. For low latency one would have 2 periods per buffer. Your 256 samples above seems a sensible enough size for a period, with the entire ring buffer being 512 samples. With a bit of clever tweaking, (i.e. in Linux) one could pick a 64byte boundary within the period and start outputting samples, and they will reach the speakers, thus not having to wait for the period to end. It would be a sort of buffer TX cut in feature. The FFT issue has nothing to do with sound card capabilities, but there is no reason why the FFT window should have to be in sync with audio buffer periods. I don't understand why or if FFT is used for CW TX anyway. I would have thought that FFT would only be needed on CW RX. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Cw Latency Problem Solved?
Eric Wachsmann - FlexRadio wrote: Let me give you the skinny right from the horses mouth. Here's what I did: I was using a laptop (P4 ~2GHz) with a FireBox. I set the FireBox to 6ms on the FireBox control panel. This could probably go lower on a more powerful machine. I then set the PowerSDR buffers to 512 for the Audio and DSP. I set the FireBox and PowerSDR to use 96kHz sampling rate. At this speed, our prospective customer was able to send 50WPM using the soundcard monitor (not an external keyer). This is the first time that we have tried this experiment at high speed since we added 96kHz support. Previous attempts at this speed all led to us directing our customers to use external keyers for high speed CW. The long and short of this is that with the right setup (small buffers, low latency, fast PC, etc), high speed semi-break in CW is possible with the SDR-1000 TODAY! Eric Wachsmann FlexRadio Systems Just out of curiosity, what is the real reason for the latency? I use Linux, and users can get high quality, reliable 2ms latency on a very modest PC. That 2ms latency is with a Linux application called Ardour, that users use for real time audio capture, effects and playback. The same latency should be able to be achieved with any Linux application. So, is this latency problem windows specific? Kind Regards James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
Re: [Flexradio] Cw Latency Problem Solved?
Alberto I2PHD wrote: James Courtier-Dutton wrote: Just out of curiosity, what is the real reason for the latency? I use Linux, and users can get high quality, reliable 2ms latency on a very modest PC. That 2ms latency is with a Linux application called Ardour, that users use for real time audio capture, effects and playback. The same latency should be able to be achieved with any Linux application. I know almost nothing about Linux, but a friend of mine who does, once told me that the Linux kernel has some long paths in the disk I/O management area that run with interrupts disabled. I wonder how this could allow to have a guarantee of 2ms latency. But, as said, my knowledge of Linux is nil. 73 Alberto I2PHD One has to be careful in order to get the 2ms latency. For example use ck kernels. These are latency tuned kernels that remove the long paths in the disk I/O management that you mention. ck kernels also place some restrictions on which modules one can load, so the ck just don't include the modules that adversely influence latency. For example, use ext2/ext3 and not reiserfs. Low latency has trade offs though. In order to get low latency, one has to slightly reduce the overall CPU and I/O processing power of the system as a whole. E.g. One gets the low latency, but it will take just slightly longer to compile a kernel. James ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
