Re: [Flexradio] Manual notch filter?
True but I think you already know I did HMM using mixtures of Gaussians in 1986 in possibly the best set of technical papers I ever wrote at our common place of business. In a more refined version of it later, applied to Markov chains and not to continuous time and space stochastic processes, it was Desjardin's vote for paper of the year because he loudly proclaimed it so in a meeting with management. Between the several of us here with this experience, we definitely know enough to tackle this problem. That said, we are definitely going to have make this user tunable. On my new supercomputer, with a Intel QX6880 (Core 2 Quad Extreme), and a high end GPU graphics card with its 128 little floating point supercomputers and Intel's top of the line motherboard, I will be able run at least my Markov chain on a mixture of a few gaussians since the solution for the separated Ricatti equations for the covariance is a simple 2nd order ODE and the conditional mean can be quantized in time, discretized in value to the point it applies. But if I were running a 3 GHz Sempron, I probably would give up 10 dB of perfection to get 10 dB of suppression and still run! The extended Kalman Filter and smoother is particularly well suited to handling the mixture of Gaussian stochastic processes in lots of cases. When I successfully demodulated the Soviet VEGA balloon probe transmission for Ed Posner at JPL this was exactly what I used. It definitely paid to have a Cray supercomputer in those days! Now, my new supercomputer on my desk will outperform it by a lot in scalar arithmetic but with SSE4 and EMT64, in all but a few examples, it will nearly equal it in vector performance with the exception of scatter gather to the vectors of course. For shorter vectors, less than a vector of vectors, the Core 2 Quad extreme will all outperform the Cray 2 because of the huge startup latency in the memory bandwidth on the Cray. What was it Seymour said? Something like It is a computer design I dashed off and made from personal computer parts. The memory bus frequency on 64 bit wide memory is 800 MHz on my desktop! I decided to forego the high speed memory bus technology, that which will natively support the full 1.33 GHz FSB, because Intel does not yet believe in it enough to put out a motherboard. The one I chose, takes the Core 2 Quad 1.33 GHz FSB and interfaces it to the 800 MHz memory bus seamlessly. I can live with 1.25 nsec clocks to memory! With PCI-E, I will have better I/O than we did on the Cray 2! FORGET THE GOOD OLD DAYS. We are in them. Bob N4HY Frank Brickle wrote: On 7/11/07, *Jim Lux* [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: AKA an adaptive signal canceller. You adapt to find the strongest signal (in time/frequency, as with radar STAP), subtract it from the input. Then find the next strongest signal, subtract it, etc. That's one way, but it's not what Bob was talking about. There are different approaches that really do rely on estimating inverse filters. The chief differences depend on whether you can make Gaussian assumptions about the interferers. They are all power independent, however. 73 Frank AB2KT -- Robert W. McGwier, Ph.D. Center for Communications Research 805 Bunn Drive Princeton, NJ 08540 (609)-924-4600 (sig required by employer) ___ 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] Manual notch filter?
Bob McGwier wrote: True but I think you already know I did HMM using mixtures of Gaussians in 1986 in possibly the best set of technical papers I ever wrote at our common place of business. Yeah, but I was thinking as well of ICA here. Also, I'm pretty convinced there is an LPC-codebook-based heuristic version of this that depends on one-time work, s.t. the online work is mostly search. The order of the LPC polynomial and the size of the excitation codebook representing splatter are a lot smaller than what you need to reconstruct high-quality signal of interest. 73 Frank AB2KT ___ 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] Manual notch filter?
At 08:18 AM 7/16/2007, Bob McGwier wrote: True but I think you already know I did HMM using mixtures of Gaussians in 1986 in possibly the best set of technical papers I ever wrote at our common place of business. I assume these weren't published in IEEE publications? (or at least not in something indexed in IEEE Xplore). Where might one find them? James Lux, P.E. Spacecraft Radio Frequency Subsystems Group Flight Communications Systems Section Jet Propulsion Laboratory, Mail Stop 161-213 4800 Oak Grove Drive Pasadena CA 91109 tel: (818)354-2075 fax: (818)393-6875 ___ 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] Manual notch filter?
MUSIC was invented where Frank and I worked for over 20 years together in the middle 1960's. It can be a problem living behind locked doors marked SHUT UP AS YOU LEAVE. But your point is well taken. One or more of these existing algorithms can be made to work. There is a large body of literature all over the place but in especially the bistatic radar literature it is very popular where you are always working to find the weak signal amongst the yelling throng. We will find something implementable that does not carry us into the next leap in Moore's law to accomplish. Bob Jim Lux wrote: At 11:41 AM 7/11/2007, Bob McGwier wrote: Here is the grand experiment we are going to try when we finally get to calm down from the Flex5000 rush to finish. I have done enough matlab/octave experimentation to expect it to work so long as we define what it is we mean by work. Suppose you are listening to weak signal A. Strong signal B comes on and its main power is well out of your passband but the splatter or sidebands are in your passband and harms your ability to hear signal A.The mathematical idea is that the portion of the signal B that is in your passband is correlated with the main signal that is out of your passband. It is strongly correlated and we should be able to derive a filter that will predict a version of the signal that is IN your passband. The property of the signal we will optimize on is to reduce the energy of the interference to the best of our ability. If we get 20 dB reduction of the inband interference from an out of band interferer, I will consider it a victory. Much more than that and I will consider it to be a major league success. AKA an adaptive signal canceller. You adapt to find the strongest signal (in time/frequency, as with radar STAP), subtract it from the input. Then find the next strongest signal, subtract it, etc. MUSIC, ESPRIT, etc. all implement various forms of this. With something like PSK31 as the interfering signal (or, possibly CW, and even more remotely possible, ssb voice), you've actually got some side information as to the structure of the interfering signal, which reduces the space over which the algorithm has to work. It's basically a signal estimation problem, and there's a lot of theory out there to draw from, both in radio and acoustics. Early significant similar applications were cancelling 60 Hz artifacts in EKG and EEGs by guys like Widrow in the 1960s. There was a good review article in IEEE Proceedings in the late 70s, early80s that talked about this. The papers by Schmidt describe how MUSIC works quite nicely. Lately, there's been a lot of work using multiple antennas, so you get spectral, spatial, and temporal information. 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 Knowledge Base: http://kb.flex-radio.com/ FlexRadio Homepage: http://www.flex-radio.com/ -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair If you're going to be crazy, you have to get paid for it or else you're going to be locked up. Hunter S. Thompson ___ 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] Manual notch filter?
If we were rendering in OpenGL, that would come for free and along for the ride. Yes, I am on my hobby horse. I do not like harming the performance of the overall radio because we are afraid somebody might have a ten generation old graphics card. Please, somebody give me some more ammo. Bob Peter G. Viscarola wrote: I like this idea quite a bit. Mainly because I use this concept all the time in other applications (IDE, Paint Shop Pro, Word, etc). I set my sights much lower. I'm just hoping some day in the distant future we'll be able to re-size the panadapter display that we already have. Ah, to dream... de Peter K1PGV ___ 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/ -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair If you're going to be crazy, you have to get paid for it or else you're going to be locked up. Hunter S. Thompson ___ 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] Manual notch filter?
At 08:25 PM 7/10/2007 -0400, you wrote: Hi Ray, Point well taken. I shouldn't have described what I had in mind as splatter. Over modulation would probably be more correct. I DX foreign medium wave stations from Asia and the Pacific, and the #1 reason this type of DXing is a big challenge is due to the wide signals from domestic (North American) broadcasters, especially the 50kw flamethrowers in the vicinity. For instance, when I tune 1017 kHz, A3Z Tonga with my SDR-1000, I expect some QRM from any domestics on 1020. However, even with directional Beverages and phased arrays I sometimes have problems with KOMO 1000 (Seattle) putting out a swath of energy and monkey chatter that affects 1017 kHz (noticed when tuning in LSB to avoid the nearer station on 1020). That's why I was thinking maybe a broad notch that I could manual drop on 1000 kHz (for instance) would help in this regard. The challenges of foreign MW DXing are not unlike those of ham radio contesting. The SDR-1000 is the best radio I've encountered for this purpose, when coupled with some carefully-chosen low pass filtering. 73, Guy KE7MAV Hi, Have you tried RF phasing to reduce local MF interference? For example you would be receiving A3Z on your phased array or Beverage and you can be receiving KOMO on a small loop antenna. Combine the signals and adjust the loop so its phase cancels KOMO on your DX antenna. You could also use a small whip for KOMO and use a separate combiner/phase shift circuit to do the same thing. MFJ used to market such a device ... designed for HF ... however I have heard of dxers modifying it for MF. Personally I have used this kind of 'RF phasing' for qrm rejection with my interest in Crystal Radio DXing. It takes a little getting used to but it works. I bring the antenna into the shack into a kind of 2 stage antenna tuner (2 high Q circuits in series) carefully adjust both circuits to maximize the DX and minimize the QRM. In my experience it is easier to deal with the interference of weak signals before detection. Jim VE3CI ___ 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] Manual notch filter?
Yes, I've done this before with the Radio Plus Quantum Phaser and my current Wellbrook phased array. Some of my MW DX friends have done extensive work in this area by modifying the MFJ phaser, or building Misek-based units such as the phasers Dallas Lankford designs. Mark Connelly in particular is leading the pack with phasing approaches. His Web site is a wealth of information: http://www.qsl.net/wa1ion/ Part of the difficulty in phasing semi-locals from my usual DXpedition locations at the WA coast is the combination of groundwave and skywave during the prime sunrise/sunset DX windows. Arrival angles of the foreign DX varies a lot at sunrise, too, and makes it very tough to impossible to achieve a steady null. Guy KE7MAV -Original Message- From: Jim Dunstan [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 11, 2007 9:47 AM To: [EMAIL PROTECTED]; flexradio@flex-radio.biz Subject: Re: [Flexradio] Manual notch filter? SNIP Hi, Have you tried RF phasing to reduce local MF interference? For example you would be receiving A3Z on your phased array or Beverage and you can be receiving KOMO on a small loop antenna. Combine the signals and adjust the loop so its phase cancels KOMO on your DX antenna. You could also use a small whip for KOMO and use a separate combiner/phase shift circuit to do the same thing. MFJ used to market such a device ... designed for HF ... however I have heard of dxers modifying it for MF. Personally I have used this kind of 'RF phasing' for qrm rejection with my interest in Crystal Radio DXing. It takes a little getting used to but it works. I bring the antenna into the shack into a kind of 2 stage antenna tuner (2 high Q circuits in series) carefully adjust both circuits to maximize the DX and minimize the QRM. In my experience it is easier to deal with the interference of weak signals before detection. Jim VE3CI ___ 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] Manual notch filter?
All, As I was [one] of the submitters of the manual notch filter, I have given some thought on how it can be implemented. Open discussion. I like to click on a signal to do something with it, and I am dedicated to the mouse. However, that is not going to work, as clicking on a signal moves the frequency there. How about holding down CTR then clicking on the signal? A CTR double click removes it; another CTR click on another freq adds another notch. Shift click anywhere removes all notches. The depth/freq width is preset in the menu. Another important thing is to show the notch(s) on the display. Simple but effective. I am familiar with MixW notch, and it uses a drop down window. That is cumbersome and slow compared to a CTR click. 73, Chas, w1cg At 06:47 PM 7/10/2007, Eric Wachsmann wrote: There are multiple issues at hand here. First, the technical aspect of how to implement the filter. I'm sure there are latency considerations unless we somehow combined this into our existing RX filter. Those issues are really for our DSP gurus N4HY and AB2KT to figure out. While there are questions in that arena, I suspect the more problematic issue at hand is how to interface with the notch. We have just about exhausted the combinations of mouse clicks/drags with the display. Adding another interactive element could easily cause (more) confusion. We will tread carefully before adding further special handling cases to the display as a result. As has been mentioned previously, we are focused currently on the launch of the FLEX-5000. As such, I wouldn't expect a feature like this to jump out in the next day/week/month or two. But don't let that keep you from discussing such ideas. Keep the thoughts flowing. Typically the better laid out the plan before we go to code it, the faster the process and the more quickly it converges into a functional feature. Eric Wachsmann FlexRadio Systems -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] radio.biz] On Behalf Of Tim Ellison Sent: Tuesday, July 10, 2007 5:29 PM To: Guy Atkins Cc: flexradio@flex-radio.biz Subject: Re: [Flexradio] Manual notch filter? The notch filter should be able to work anywhere in the passband of the audio ~180 KHz when running at 192 KHz sampling rate. Eric has the last word on that. -Tim -Original Message- From: Guy Atkins [mailto:[EMAIL PROTECTED] Sent: Tuesday, July 10, 2007 6:22 PM To: Tim Ellison Cc: flexradio@flex-radio.biz Subject: RE: [Flexradio] Manual notch filter? Tim, Would a notch like this be able to work outside of the filter passband, but within the panadapter window? It would be great to put a wide manual notch on an adjacent channel signal to knock down splatter. However, this might work better (or at all) with software phasing algorithms such as Gerald mentioned in his Dayton presentation. Guy Atkins KE7MAV Puyallup, WA ___ 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/ ___ 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/ ___ 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] Manual notch filter?
Frank's approach of using a 3D style control sounds exciting and I'm guessing lends itself to many other functions for which it is currently difficult to provide a suitable display/interaction metaphor. However, perhaps in the short term, one possible way to disambiguate mouse click intent might be to employ alternate tools other than the standard mouse pointer - e.g. a notch tool which could allow selection and drag-and-drop within the panadapter. Maybe this approach could also be applied to other as yet undreamt of functions. 73, Pete, n3evl -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] radio.biz] On Behalf Of Charles Greene Sent: Wednesday, July 11, 2007 1:20 PM To: Eric Wachsmann; FlexRadio@flex-radio.biz Subject: Re: [Flexradio] Manual notch filter? All, As I was [one] of the submitters of the manual notch filter, I have given some thought on how it can be implemented. Open discussion. I like to click on a signal to do something with it, and I am dedicated to the mouse. However, that is not going to work, as clicking on a signal moves the frequency there. How about holding down CTR then clicking on the signal? A CTR double click removes it; another CTR click on another freq adds another notch. Shift click anywhere removes all notches. The depth/freq width is preset in the menu. Another important thing is to show the notch(s) on the display. Simple but effective. I am familiar with MixW notch, and it uses a drop down window. That is cumbersome and slow compared to a CTR click. 73, Chas, w1cg At 06:47 PM 7/10/2007, Eric Wachsmann wrote: There are multiple issues at hand here. First, the technical aspect of how to implement the filter. I'm sure there are latency considerations unless we somehow combined this into our existing RX filter. Those issues are really for our DSP gurus N4HY and AB2KT to figure out. While there are questions in that arena, I suspect the more problematic issue at hand is how to interface with the notch. We have just about exhausted the combinations of mouse clicks/drags with the display. Adding another interactive element could easily cause (more) confusion. We will tread carefully before adding further special handling cases to the display as a result. As has been mentioned previously, we are focused currently on the launch of the FLEX-5000. As such, I wouldn't expect a feature like this to jump out in the next day/week/month or two. But don't let that keep you from discussing such ideas. Keep the thoughts flowing. Typically the better laid out the plan before we go to code it, the faster the process and the more quickly it converges into a functional feature. Eric Wachsmann FlexRadio Systems -Original Message- From: [EMAIL PROTECTED] [mailto:flexradio- [EMAIL PROTECTED] radio.biz] On Behalf Of Tim Ellison Sent: Tuesday, July 10, 2007 5:29 PM To: Guy Atkins Cc: flexradio@flex-radio.biz Subject: Re: [Flexradio] Manual notch filter? The notch filter should be able to work anywhere in the passband of the audio ~180 KHz when running at 192 KHz sampling rate. Eric has the last word on that. -Tim -Original Message- From: Guy Atkins [mailto:[EMAIL PROTECTED] Sent: Tuesday, July 10, 2007 6:22 PM To: Tim Ellison Cc: flexradio@flex-radio.biz Subject: RE: [Flexradio] Manual notch filter? Tim, Would a notch like this be able to work outside of the filter passband, but within the panadapter window? It would be great to put a wide manual notch on an adjacent channel signal to knock down splatter. However, this might work better (or at all) with software phasing algorithms such as Gerald mentioned in his Dayton presentation. Guy Atkins KE7MAV Puyallup, WA ___ 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/ ___ 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/ ___ 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] Manual notch filter?
A couple of observations... 1. ) I think a simple notch filter that is outside of the filter pass band, or its immediate skirts, is NOT going to effect anything that you hear within the filter pass band. Any transmitter splatter or intermod products that occurs before the ADC can not be removed by an outside of the passband notch filter after the ADC. There may be some smart processing that would be beneficial. 2) A manual notch filter ( or multiple filters ) inside of the passband could be useful. This filter would need to stay RF frequency locked as the receiver is tuned (i.e. not locked to the post detection audio frequency). 3) Notch filters (both manual and automatic ) need to be before the AGC loop such that the receiver gains is not suppressed by the amplitude of the notched signal. 4) With the full dynamic range of signal available from a SDR through VAC to external programs, the DSP in external programs can be nearly as good at the DSP in the SDR ( either by existing design or new improvements ) Think of the external special purpose programs as a second IF signal processor. AL, K0VM ___ 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] Manual notch filter?
Here is the grand experiment we are going to try when we finally get to calm down from the Flex5000 rush to finish. I have done enough matlab/octave experimentation to expect it to work so long as we define what it is we mean by work. Suppose you are listening to weak signal A. Strong signal B comes on and its main power is well out of your passband but the splatter or sidebands are in your passband and harms your ability to hear signal A.The mathematical idea is that the portion of the signal B that is in your passband is correlated with the main signal that is out of your passband. It is strongly correlated and we should be able to derive a filter that will predict a version of the signal that is IN your passband. The property of the signal we will optimize on is to reduce the energy of the interference to the best of our ability. If we get 20 dB reduction of the inband interference from an out of band interferer, I will consider it a victory. Much more than that and I will consider it to be a major league success. Bob Ray Andrews wrote: Guy, Of course, a notch filter could be coded to work anywhere in the range of the panadapter display. However, don't hold your breath waiting for it to do what you want. If the splatter is caused by an improperly adjusted transmitter somewhere else on the band, then the splatter consists of spurious signals that are within your desired pass band. Notching out the main signal will NOT reduce the spurious signals -- they have already been put there by the dirty transmitter. The only way that this type of notch filter would help is if the splatter is caused by overload in your receiver, either in the hardware or in the signal processing software. Sorry, 73, Ray, K9DUR ___ 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/ -- Robert W. McGwier, Ph.D. Center for Communications Research 805 Bunn Drive Princeton, NJ 08540 (609)-924-4600 (sig required by employer) ___ 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] Manual notch filter?
Wow! until this I had not thought there was any bennfit to out of passband notch. Jim - W4YXU - Original Message - From: Bob McGwier [EMAIL PROTECTED] To: Ray Andrews [EMAIL PROTECTED] Cc: flexradio@flex-radio.biz Sent: Wednesday, July 11, 2007 1:41 PM Subject: Re: [Flexradio] Manual notch filter? Here is the grand experiment we are going to try when we finally get to calm down from the Flex5000 rush to finish. I have done enough matlab/octave experimentation to expect it to work so long as we define what it is we mean by work. Suppose you are listening to weak signal A. Strong signal B comes on and its main power is well out of your passband but the splatter or sidebands are in your passband and harms your ability to hear signal A.The mathematical idea is that the portion of the signal B that is in your passband is correlated with the main signal that is out of your passband. It is strongly correlated and we should be able to derive a filter that will predict a version of the signal that is IN your passband. The property of the signal we will optimize on is to reduce the energy of the interference to the best of our ability. If we get 20 dB reduction of the inband interference from an out of band interferer, I will consider it a victory. Much more than that and I will consider it to be a major league success. Bob Ray Andrews wrote: Guy, Of course, a notch filter could be coded to work anywhere in the range of the panadapter display. However, don't hold your breath waiting for it to do what you want. If the splatter is caused by an improperly adjusted transmitter somewhere else on the band, then the splatter consists of spurious signals that are within your desired pass band. Notching out the main signal will NOT reduce the spurious signals -- they have already been put there by the dirty transmitter. The only way that this type of notch filter would help is if the splatter is caused by overload in your receiver, either in the hardware or in the signal processing software. Sorry, 73, Ray, K9DUR ___ 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/ -- Robert W. McGwier, Ph.D. Center for Communications Research 805 Bunn Drive Princeton, NJ 08540 (609)-924-4600 (sig required by employer) ___ 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/ -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.476 / Virus Database: 269.10.2/891 - Release Date: 7/8/2007 6:32 PM ___ 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] Manual notch filter?
All, As I was [one] of the submitters of the manual notch filter, I have given some thought on how it can be implemented. Open discussion. I like to click on a signal to do something with it, and I am dedicated to the mouse. However, that is not going to work, as clicking on a signal moves the frequency there. How about holding down CTR then clicking on the signal? How about dragging a custom graphical control over the top of the offending signal (a control that reproduces to some reasonable limit, say five)? Control click is just too awkward and mistake prone. Besides, we're probably going to want to implement this control so that it can be made wider or narrower. Why not do it on the control itself instead of having more screen real estate somewhere with numbers on it? This is not an everyday function. This suggests we indeed want to keep dragging some sort of suitable, visually appealing control over onto the Panadapter or Spectrum displays for each manual filter. When not in use, perhaps it/they sit on the somewhat useless far lefthand side of the panadapter (or spectrum) display. Back in the old Flex forum, I put up pictures of how this might work. Perhaps they are still there. Larry Wo0Z ___ 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] Manual notch filter?
I like this idea quite a bit. Mainly because I use this concept all the time in other applications (IDE, Paint Shop Pro, Word, etc). Eric Wachsmann FlexRadio Systems -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 11, 2007 1:08 PM To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; FlexRadio@flex-radio.biz Subject: RE: [Flexradio] Manual notch filter? Frank's approach of using a 3D style control sounds exciting and I'm guessing lends itself to many other functions for which it is currently difficult to provide a suitable display/interaction metaphor. However, perhaps in the short term, one possible way to disambiguate mouse click intent might be to employ alternate tools other than the standard mouse pointer - e.g. a notch tool which could allow selection and drag-and-drop within the panadapter. Maybe this approach could also be applied to other as yet undreamt of functions. 73, Pete, n3evl ___ 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] Manual notch filter?
I like this idea quite a bit. Mainly because I use this concept all the time in other applications (IDE, Paint Shop Pro, Word, etc). I set my sights much lower. I'm just hoping some day in the distant future we'll be able to re-size the panadapter display that we already have. Ah, to dream... de Peter K1PGV ___ 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] Manual notch filter?
At 10:03 AM 7/11/2007 -0700, you wrote: Yes, I've done this before with the Radio Plus Quantum Phaser and my current Wellbrook phased array. Some of my MW DX friends have done extensive work in this area by modifying the MFJ phaser, or building Misek-based units such as the phasers Dallas Lankford designs. Mark Connelly in particular is leading the pack with phasing approaches. His Web site is a wealth of information: http://www.qsl.net/wa1ion/ Part of the difficulty in phasing semi-locals from my usual DXpedition locations at the WA coast is the combination of groundwave and skywave during the prime sunrise/sunset DX windows. Arrival angles of the foreign DX varies a lot at sunrise, too, and makes it very tough to impossible to achieve a steady null. Guy KE7MAV Hi, I see you are no novice regards ekeing out MW dx. I also find the flexradio an excellent DXing receiver, which makes me think there is a market for a similar receive only unit, built on a single board. Jim, VE3CI ___ 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] Manual notch filter?
On 7/11/07, Bob McGwier [EMAIL PROTECTED] wrote: ...It is strongly correlated and we should be able to derive a filter that will predict a version of the signal that is IN your passband. The property of the signal we will optimize on is to reduce the energy of the interference to the best of our ability... Lest we become prematurely enthusiastic...this is a ways off, at least as a routine procedure. Leaving aside the purely technical issues involved, we still need to be aware that *any* processing of this kind is going to involve significant latency. Like any kind of error correction, it depends on having a certain amount of leading data to chew on, with results that can be applied retrospectively to the output data stream. Based on what we know now, the necessary latency will be of roughly the same order as you get from robust digital voice on HF. *However* there is another approach which will yield far lower latency but at the expense of voice quality (although not intelligibility). This approach involves inserting a vocoding stage between the radio demod and the audio output. The result will be approximately cellphone-quality speech, but close to instantaneous response. The interference mitigation operates not on the signal but rather on the reduced vocoder coefficients. This is a lossy procedure, and there's no way to reconstruct what's thrown away in the compression process. But it reduces dramatically the search and computation space for both the inverse interferer filter and and cleaned-up signal of interest. If ever there were a reason to have all the DSP processing on a separate general-purpose CPU host, this kind of cleanup would surely have to rank near the top. 73 Frank AB2KT -- next part -- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070711/3c334d17/attachment.html ___ 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] Manual notch filter?
At 11:41 AM 7/11/2007, Bob McGwier wrote: Here is the grand experiment we are going to try when we finally get to calm down from the Flex5000 rush to finish. I have done enough matlab/octave experimentation to expect it to work so long as we define what it is we mean by work. Suppose you are listening to weak signal A. Strong signal B comes on and its main power is well out of your passband but the splatter or sidebands are in your passband and harms your ability to hear signal A.The mathematical idea is that the portion of the signal B that is in your passband is correlated with the main signal that is out of your passband. It is strongly correlated and we should be able to derive a filter that will predict a version of the signal that is IN your passband. The property of the signal we will optimize on is to reduce the energy of the interference to the best of our ability. If we get 20 dB reduction of the inband interference from an out of band interferer, I will consider it a victory. Much more than that and I will consider it to be a major league success. AKA an adaptive signal canceller. You adapt to find the strongest signal (in time/frequency, as with radar STAP), subtract it from the input. Then find the next strongest signal, subtract it, etc. MUSIC, ESPRIT, etc. all implement various forms of this. With something like PSK31 as the interfering signal (or, possibly CW, and even more remotely possible, ssb voice), you've actually got some side information as to the structure of the interfering signal, which reduces the space over which the algorithm has to work. It's basically a signal estimation problem, and there's a lot of theory out there to draw from, both in radio and acoustics. Early significant similar applications were cancelling 60 Hz artifacts in EKG and EEGs by guys like Widrow in the 1960s. There was a good review article in IEEE Proceedings in the late 70s, early80s that talked about this. The papers by Schmidt describe how MUSIC works quite nicely. Lately, there's been a lot of work using multiple antennas, so you get spectral, spatial, and temporal information. 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 Knowledge Base: http://kb.flex-radio.com/ FlexRadio Homepage: http://www.flex-radio.com/
Re: [Flexradio] Manual notch filter?
On 7/11/07, Jim Lux [EMAIL PROTECTED] wrote: AKA an adaptive signal canceller. You adapt to find the strongest signal (in time/frequency, as with radar STAP), subtract it from the input. Then find the next strongest signal, subtract it, etc. That's one way, but it's not what Bob was talking about. There are different approaches that really do rely on estimating inverse filters. The chief differences depend on whether you can make Gaussian assumptions about the interferers. They are all power independent, however. 73 Frank AB2KT -- next part -- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070711/222db0f4/attachment.html ___ 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] Manual notch filter?
The manual notch filter is important. All of the programming effort for the past few months has been towards getting the FLEX-5000 working with PowerSDR and not on providing new features. Enhancements and new features will get put back on the programming to do list once support for the FLEX-5000 is complete. -Tim -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, July 10, 2007 10:57 AM To: flexradio@flex-radio.biz Subject: [Flexradio] Manual notch filter? Over the past 8 months, there has been a couple of enhancement requests to add Manual Notch filter for CW. I always thought a manual notch could be useful on PowerSDR, same as it is on other conventional steamboat rigs. But this is one of the few good enhancement requests that has not been implemented yet. IMHO :) I assume there must be programming issues that make a manual notch very difficult with high cpu overhead, or can't do . Or is it just on the long list of things to do? Could one of of you Gurus comment please? Thanks. 73 John N3WT ___ 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/ ___ 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] Manual notch filter?
I agree a manual notch filter would be useful and would be even better if you could right click the offending signal when in panadapter display and have a selection to apply notch filter. Also it should be available in other modes as well as CW. Just some wishful thinking :-) Dave WO2X Over the past 8 months, there has been a couple of enhancement requests to add Manual Notch filter for CW. I always thought a manual notch could be useful on PowerSDR, same as it is on other conventional steamboat rigs. ___ 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] Manual notch filter?
Maybe implemented as a reverse of the present bandpass. Would really help in getting the 1khz by +40db pks31 signal down to a mild roar! Jim - W4YXU - Original Message - From: Tim Ellison [EMAIL PROTECTED] To: [EMAIL PROTECTED]; flexradio@flex-radio.biz Sent: Tuesday, July 10, 2007 10:14 AM Subject: Re: [Flexradio] Manual notch filter? The manual notch filter is important. All of the programming effort for the past few months has been towards getting the FLEX-5000 working with PowerSDR and not on providing new features. Enhancements and new features will get put back on the programming to do list once support for the FLEX-5000 is complete. -Tim -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, July 10, 2007 10:57 AM To: flexradio@flex-radio.biz Subject: [Flexradio] Manual notch filter? Over the past 8 months, there has been a couple of enhancement requests to add Manual Notch filter for CW. I always thought a manual notch could be useful on PowerSDR, same as it is on other conventional steamboat rigs. But this is one of the few good enhancement requests that has not been implemented yet. IMHO :) I assume there must be programming issues that make a manual notch very difficult with high cpu overhead, or can't do . Or is it just on the long list of things to do? Could one of of you Gurus comment please? Thanks. 73 John N3WT ___ 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/ ___ 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/ -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.476 / Virus Database: 269.10.2/893 - Release Date: 7/9/2007 5:22 PM ___ 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] Manual notch filter?
How about a click, drag and set filter in addition to a fixed width notch filter? Place the crosshairs on one side of the offending signal and define the filter width by dragging dynamically created filter width across it, nulling it out. -Tim Integrated Technical Services www.itsco.com -Original Message- From: Jim McLester [mailto:[EMAIL PROTECTED] Sent: Tuesday, July 10, 2007 1:14 PM To: Tim Ellison; [EMAIL PROTECTED]; flexradio@flex-radio.biz Subject: Re: [Flexradio] Manual notch filter? Maybe implemented as a reverse of the present bandpass. Would really help in getting the 1khz by +40db pks31 signal down to a mild roar! Jim - W4YXU - Original Message - From: Tim Ellison [EMAIL PROTECTED] To: [EMAIL PROTECTED]; flexradio@flex-radio.biz Sent: Tuesday, July 10, 2007 10:14 AM Subject: Re: [Flexradio] Manual notch filter? The manual notch filter is important. All of the programming effort for the past few months has been towards getting the FLEX-5000 working with PowerSDR and not on providing new features. Enhancements and new features will get put back on the programming to do list once support for the FLEX-5000 is complete. -Tim -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, July 10, 2007 10:57 AM To: flexradio@flex-radio.biz Subject: [Flexradio] Manual notch filter? Over the past 8 months, there has been a couple of enhancement requests to add Manual Notch filter for CW. I always thought a manual notch could be useful on PowerSDR, same as it is on other conventional steamboat rigs. But this is one of the few good enhancement requests that has not been implemented yet. IMHO :) I assume there must be programming issues that make a manual notch very difficult with high cpu overhead, or can't do . Or is it just on the long list of things to do? Could one of of you Gurus comment please? Thanks. 73 John N3WT ___ 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/ ___ 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/ -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.476 / Virus Database: 269.10.2/893 - Release Date: 7/9/2007 5:22 PM ___ 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] Manual notch filter?
I agree a manual notch filter would be useful and would be even better if you could right click the offending signal when in panadapter display and have a selection to apply notch filter. Also it should be available in other modes as well as CW. Just some wishful thinking :-) Dave WO2X I've advocated that there be some kind of quiver of manual notch filters that you could drag and drop over the offending signals. Unlike conventional notch filters, they would stay in place until you dragged them off the panadapter or spectrum displays wherever you could place them. I also suggested it look kind of like an arrow so there was room at the top of the gadget to use the scroll wheel (after a click on the top) to adjust the notch's width. The right click isn't the right solution, because it's already tied up in the very important click-to-vfo functionality. Larry Wo0Z PS, an interesting use for a manual notch that has just occurred to me and could be SDR specific would be to informally create a comb filter for RTTY. I don't know if one always would want one, but there have been times where overlapping RTTY signals have made me wish for a comb, but maybe this sort of feature would be enough in terms of having it. I don't know if I'd want a full time comb filter for RTTY because one can tune well enough without a perfect shift. Start tossing in a comb filter and more precise tuning is probably needful. ___ 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] Manual notch filter?
Interestingly, in the digi world (PSK31) both HamScope and MixW have notch filters built right into their waterfall's. You simply right click on the offending signal and notch it out (up to about 40db I think). de ken n9vv [EMAIL PROTECTED] wrote: I agree a manual notch filter would be useful and would be even better if you could right click the offending signal when in panadapter display and have a selection to apply notch filter. Also it should be available in other modes as well as CW. Just some wishful thinking :-) Dave WO2X I've advocated that there be some kind of quiver of manual notch filters that you could drag and drop over the offending signals. Unlike conventional notch filters, they would stay in place until you dragged them off the panadapter or spectrum displays wherever you could place them. I also suggested it look kind of like an arrow so there was room at the top of the gadget to use the scroll wheel (after a click on the top) to adjust the notch's width. The right click isn't the right solution, because it's already tied up in the very important click-to-vfo functionality. Larry Wo0Z PS, an interesting use for a manual notch that has just occurred to me and could be SDR specific would be to informally create a comb filter for RTTY. I don't know if one always would want one, but there have been times where overlapping RTTY signals have made me wish for a comb, but maybe this sort of feature would be enough in terms of having it. I don't know if I'd want a full time comb filter for RTTY because one can tune well enough without a perfect shift. Start tossing in a comb filter and more precise tuning is probably needful. ___ 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/ ___ 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] Manual notch filter?
Tim, Would a notch like this be able to work outside of the filter passband, but within the panadapter window? It would be great to put a wide manual notch on an adjacent channel signal to knock down splatter. However, this might work better (or at all) with software phasing algorithms such as Gerald mentioned in his Dayton presentation. Guy Atkins KE7MAV Puyallup, WA ___ 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] Manual notch filter?
The notch filter should be able to work anywhere in the passband of the audio ~180 KHz when running at 192 KHz sampling rate. Eric has the last word on that. -Tim -Original Message- From: Guy Atkins [mailto:[EMAIL PROTECTED] Sent: Tuesday, July 10, 2007 6:22 PM To: Tim Ellison Cc: flexradio@flex-radio.biz Subject: RE: [Flexradio] Manual notch filter? Tim, Would a notch like this be able to work outside of the filter passband, but within the panadapter window? It would be great to put a wide manual notch on an adjacent channel signal to knock down splatter. However, this might work better (or at all) with software phasing algorithms such as Gerald mentioned in his Dayton presentation. Guy Atkins KE7MAV Puyallup, WA ___ 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] Manual notch filter?
There are multiple issues at hand here. First, the technical aspect of how to implement the filter. I'm sure there are latency considerations unless we somehow combined this into our existing RX filter. Those issues are really for our DSP gurus N4HY and AB2KT to figure out. While there are questions in that arena, I suspect the more problematic issue at hand is how to interface with the notch. We have just about exhausted the combinations of mouse clicks/drags with the display. Adding another interactive element could easily cause (more) confusion. We will tread carefully before adding further special handling cases to the display as a result. As has been mentioned previously, we are focused currently on the launch of the FLEX-5000. As such, I wouldn't expect a feature like this to jump out in the next day/week/month or two. But don't let that keep you from discussing such ideas. Keep the thoughts flowing. Typically the better laid out the plan before we go to code it, the faster the process and the more quickly it converges into a functional feature. Eric Wachsmann FlexRadio Systems -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] radio.biz] On Behalf Of Tim Ellison Sent: Tuesday, July 10, 2007 5:29 PM To: Guy Atkins Cc: flexradio@flex-radio.biz Subject: Re: [Flexradio] Manual notch filter? The notch filter should be able to work anywhere in the passband of the audio ~180 KHz when running at 192 KHz sampling rate. Eric has the last word on that. -Tim -Original Message- From: Guy Atkins [mailto:[EMAIL PROTECTED] Sent: Tuesday, July 10, 2007 6:22 PM To: Tim Ellison Cc: flexradio@flex-radio.biz Subject: RE: [Flexradio] Manual notch filter? Tim, Would a notch like this be able to work outside of the filter passband, but within the panadapter window? It would be great to put a wide manual notch on an adjacent channel signal to knock down splatter. However, this might work better (or at all) with software phasing algorithms such as Gerald mentioned in his Dayton presentation. Guy Atkins KE7MAV Puyallup, WA ___ 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/ ___ 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] Manual notch filter?
KE2SL wrote: I agree a manual notch filter would be useful and would be even better if you could right click the offending signal when in panadapter display and have a selection to apply notch filter. Also it should be available in other modes as well as CW. Just some wishful thinking :-) Your wishful thinking is required reading. It is on our to do list for inclusion in DttSP v2.0 and PowerSDR both. Dave WO2X Over the past 8 months, there has been a couple of enhancement requests to add Manual Notch filter for CW. I always thought a manual notch could be useful on PowerSDR, same as it is on other conventional steamboat rigs. -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair If you're going to be crazy, you have to get paid for it or else you're going to be locked up. Hunter S. Thompson ___ 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] Manual notch filter?
Sounds like a plan to me. Bob Jim Lux wrote: At 03:47 PM 7/10/2007, Eric Wachsmann wrote: There are multiple issues at hand here. First, the technical aspect of how to implement the filter. I'm sure there are latency considerations unless we somehow combined this into our existing RX filter. Those issues are really for our DSP gurus N4HY and AB2KT to figure out. While there are questions in that arena, I suspect the more problematic issue at hand is how to interface with the notch. We have just about exhausted the combinations of mouse clicks/drags with the display. Adding another interactive element could easily cause (more) confusion. We will tread carefully before adding further special handling cases to the display as a result. I would also suggest a small mental exercise.. separate the UI question (what are clicks,drags, etc.) from the how do I specify the notch filter to the dsp back end question. Ideally, you'd send a message to the backend saying I want a notch from frequency X to frequency Y with Z attenuation, where frequencies are specified in terms of the RF frequency to the outside world (even if you wound up clicking in terms of a relative location within the pan adapter... something should undo all the display relative aspects and turn it into a actual frequency)... The backend would get the message and either just do it, or send back a response saying, no, I can't do exactly that, what I did was A to B with C. (because of quantization or implementation constraints) Jim, W6RMK -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair If you're going to be crazy, you have to get paid for it or else you're going to be locked up. Hunter S. Thompson ___ 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] Manual notch filter?
Guy, Of course, a notch filter could be coded to work anywhere in the range of the panadapter display. However, don't hold your breath waiting for it to do what you want. If the splatter is caused by an improperly adjusted transmitter somewhere else on the band, then the splatter consists of spurious signals that are within your desired pass band. Notching out the main signal will NOT reduce the spurious signals -- they have already been put there by the dirty transmitter. The only way that this type of notch filter would help is if the splatter is caused by overload in your receiver, either in the hardware or in the signal processing software. Sorry, 73, Ray, K9DUR ___ 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] Manual notch filter?
Hi Ray, Point well taken. I shouldn't have described what I had in mind as splatter. Over modulation would probably be more correct. I DX foreign medium wave stations from Asia and the Pacific, and the #1 reason this type of DXing is a big challenge is due to the wide signals from domestic (North American) broadcasters, especially the 50kw flamethrowers in the vicinity. For instance, when I tune 1017 kHz, A3Z Tonga with my SDR-1000, I expect some QRM from any domestics on 1020. However, even with directional Beverages and phased arrays I sometimes have problems with KOMO 1000 (Seattle) putting out a swath of energy and monkey chatter that affects 1017 kHz (noticed when tuning in LSB to avoid the nearer station on 1020). That's why I was thinking maybe a broad notch that I could manual drop on 1000 kHz (for instance) would help in this regard. The challenges of foreign MW DXing are not unlike those of ham radio contesting. The SDR-1000 is the best radio I've encountered for this purpose, when coupled with some carefully-chosen low pass filtering. 73, Guy KE7MAV Original Message: - From: Ray Andrews [EMAIL PROTECTED] Date: Tue, 10 Jul 2007 19:26:23 -0400 To: [EMAIL PROTECTED], [EMAIL PROTECTED], flexradio@flex-radio.biz Subject: Re: [Flexradio] Manual notch filter? Guy, Of course, a notch filter could be coded to work anywhere in the range of the panadapter display. However, don't hold your breath waiting for it to do what you want. If the splatter is caused by an improperly adjusted transmitter somewhere else on the band, then the splatter consists of spurious signals that are within your desired pass band. Notching out the main signal will NOT reduce the spurious signals -- they have already been put there by the dirty transmitter. The only way that this type of notch filter would help is if the splatter is caused by overload in your receiver, either in the hardware or in the signal processing software. Sorry, 73, Ray, K9DUR mail2web.com What can On Demand Business Solutions do for you? http://link.mail2web.com/Business/SharePoint ___ 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/
