Re: [Flexradio] Sampling rate and buffers for CW operators?
You can actually see the effects on filter width at various sample rates and buffer sizes in the Owners manual, appendix A. In the section Filter Effects you see that the minimum filter width possible is proportional to the sample rate and inversely proportional to the buffer size. And on page 203 a series of graphs visualizes the actual filter shapes, actually measured (with a FLEX-5000), at various sample rates and buffer sizes for a 25Hz filter. The narrowest/sharpest filter possible is indeed for 48kHz sample rate and 4096 DSP Buffer. The 96kHz/4096 filter shape is the same as the 48kHz/2048 (96/4096 = 48/2048), etc. It all becomes rather dramatic at 192kHz (for a 25Hz filter) and as the illustration shows, at 192kHz/4096 it is pretty much pointless to select 25Hz and 50Hz filters as the minimum possible filter width is 70Hz (with a Blackman-Harris window) Of course, whether you can get away with a 4096 buffer size and 48kHz sample rate depends pretty much on your system set-up, as it is the highest latency setting, as the same Appendix also tries to explain. It'll be great to have all these interdependencies gone with N4HYs multirate code, because this is probably the one single, most confusing issue for PowerSDR users. (Besides, it makes the manual thinner too and I won't have to overwork my poor brain anymore trying to illustrate how all the interdependcies work ;-) 73 de Joe - AB1DO - Original Message - From: "Edward Russell" To: "'Flexradio'" Sent: Tuesday, May 12, 2009 19:25 Subject: Re: [Flexradio] Sampling rate and buffers for CW operators? Lee is using the optimal CW settings for filters. The 512 TX setting actually reduces RX latency. My only difference is the 96khz sample rate, which I change to 48khz if I need sharper filters. 96khz is pretty good except in the sub-100hz region. 73 Ed W2RF -Original Message- From: flexradio-boun...@flex-radio.biz [mailto:flexradio-boun...@flex- radio.biz] On Behalf Of Lee A Crocker Sent: Tuesday, May 12, 2009 5:50 PM To: Flexradio Subject: Re: [Flexradio] Sampling rate and buffers for CW operators? I work weak signal low band DX on CW I use filters as narrow as 25hz routinely I'm set up at 48khz DSP CW set at 4096 on RX 512 on TX. Audio buffs set at 512 The filters are noticeably steeper to the ear at these settings 73 W9OY ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex- radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Sampling rate and buffers for CW operators?
Thanks to all who responded both on and off list with some great suggestions. I've got quite a few configurations to try. I look forward to learning more about this amazing radio in the days and weeks to come... 73 Tim Nz8J -Original Message- From: flexradio-boun...@flex-radio.biz [mailto:flexradio-boun...@flex-radio.biz] On Behalf Of NZ8J Sent: Tuesday, May 12, 2009 6:42 AM To: flexradio@flex-radio.biz Subject: [Flexradio] Sampling rate and buffers for CW operators? I'm trying to get a feel for what other primarily CW operators are using for sampling rate and buffers taking the computer limitations out of the equation. Assuming the computer is robust enough to handle it, what setting do you find the best overall balance between latency and filter sharpness? I'm using a Intel quad core with 4 GB ram and I have the firewire driver and primary audio set at 192Khz sampling rate and buffer size of 2048. (Firewire at "normal" operation) The DSP buffers are set at RX=4096 and TX=2048. There appears to be little difference between the 100hz and 25 hz filters at these settings. The CPU usage is normally less than 20% running PowerSDR 1.18.0 and Logic 8 under these settings I am just learning how to operate this radio and would like to see what other cw operators are using. I am amazed by how quiet the radio is and how much easier it is to copy weak cw signals down in the noise. Thanks Tim NZ8J ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Sampling rate and buffers for CW operators?
Lee is using the optimal CW settings for filters. The 512 TX setting actually reduces RX latency. My only difference is the 96khz sample rate, which I change to 48khz if I need sharper filters. 96khz is pretty good except in the sub-100hz region. 73 Ed W2RF > -Original Message- > From: flexradio-boun...@flex-radio.biz [mailto:flexradio-boun...@flex- > radio.biz] On Behalf Of Lee A Crocker > Sent: Tuesday, May 12, 2009 5:50 PM > To: Flexradio > Subject: Re: [Flexradio] Sampling rate and buffers for CW operators? > > I work weak signal low band DX on CW > > I use filters as narrow as 25hz routinely > > I'm set up at 48khz DSP CW set at 4096 on RX 512 on TX. Audio buffs set at > 512 > > The filters are noticeably steeper to the ear at these settings > > 73 W9OY > > > > > ___ > FlexRadio Systems Mailing List > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex- > radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Sampling rate and buffers for CW operators?
I work weak signal low band DX on CW I use filters as narrow as 25hz routinely I'm set up at 48khz DSP CW set at 4096 on RX 512 on TX. Audio buffs set at 512 The filters are noticeably steeper to the ear at these settings 73 W9OY ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
[Flexradio] sampling rate and buffers
I 'Prefer' using 192kHz when DXing, lately some wide 'split spreads' have become popular. So on the 'Audio>Primary' tab, I just leave it there. 192kH 2048 Buffer Size and hear no latency when using the paddles or software cw. Funny but I do not hear any audio dropouts even with the high cpu use, but... if running CWSkimmer, which sucks cpu, I will 'SEE' a solid line where dot/dash normally are. It resumes quickly. I'm guessing that's because I have PWSDR on 'High Priority' and CWSkimmer set to a lower Priority. But on weekends, contesting, the cpu load with all the ancillary contesting/log checking can get a tad high. Especially when cluster is getting constant new 'spots'. So I drop down to 96kHz. So my question is: On the DSP tab there is another group of Buffer Settings. Phone RX 4096 TX 2048, CW RX 4096 TX 2048, Digital RX 4096 TX 2048, Wondering if someone can suggest a 'BETTER' choice? I'm mainly a cw/digital op, with occupational hearing loss but I could hear the difference when I had the Flex next to the MP. So I'm open to suggestions. ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Sampling rate and buffers for CW operators?
I use a compromise between filters and latency: 96khz with 512 buffers. Also some versions of PowerSDR have less latency than others. My branch pioneered the low latency DSP mod. I'm not sure if those changes have made it into the release branch. I think some of them are in the test branch. 73 Ed W2RF > -Original Message- > From: flexradio-boun...@flex-radio.biz [mailto:flexradio-boun...@flex- > radio.biz] On Behalf Of George Allen > Sent: Tuesday, May 12, 2009 1:37 PM > To: NZ8J; flexradio@flex-radio.biz > Subject: Re: [Flexradio] Sampling rate and buffers for CW operators? > > I also use 192KHZ and 2048 buffer size. There are a couple of > interesting relationships that I have observed. > > 1.If I use less than 192KHZ sampling rate, I get sharper filters; > but, experience latency with using my keyer. The rig appears to key > correctly; but, there is a delay between using the paddle and hearing > the side tone. To my ears, this drives me crazy and makes the rig tough > to use for CW. > > 2.If I use 192KHZ, my filters are not as sharp and I experience no > latency with the keying. It's a real pleasure to use. Even though the > filters are "not as sharp" they are still sharper than my old IC756 PRO > III. > > Thus, I use 192KHZ and 2048 buffer. > > George, K2CM > Apalachin, NY > > -Original Message- > From: NZ8J [mailto:n...@woh.rr.com] > Sent: Tuesday, May 12, 2009 6:42 AM > To: flexradio@flex-radio.biz > Subject: [Flexradio] Sampling rate and buffers for CW operators? > > > I'm trying to get a feel for what other primarily CW operators are using > for sampling rate and buffers taking the computer limitations out of the > equation. Assuming the computer is robust enough to handle it, what > setting do you find the best overall balance between latency and filter > sharpness? > > I'm using a Intel quad core with 4 GB ram and I have the firewire driver > and primary audio set at 192Khz sampling rate and buffer size of 2048. > (Firewire at "normal" operation) The DSP buffers are set at RX=4096 > and TX=2048. There appears to be little difference between the 100hz > and 25 hz filters at these settings. > > The CPU usage is normally less than 20% running PowerSDR 1.18.0 and > Logic 8 under these settings > > I am just learning how to operate this radio and would like to see what > other cw operators are using. I am amazed by how quiet the radio is and > how much easier it is to copy weak cw signals down in the noise. > > Thanks > Tim > NZ8J > > > > > ___ > FlexRadio Systems Mailing List > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex- > radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Sampling rate and buffers for CW operators?
I also use 192KHZ and 2048 buffer size. There are a couple of interesting relationships that I have observed. 1. If I use less than 192KHZ sampling rate, I get sharper filters; but, experience latency with using my keyer. The rig appears to key correctly; but, there is a delay between using the paddle and hearing the side tone. To my ears, this drives me crazy and makes the rig tough to use for CW. 2. If I use 192KHZ, my filters are not as sharp and I experience no latency with the keying. It's a real pleasure to use. Even though the filters are "not as sharp" they are still sharper than my old IC756 PRO III. Thus, I use 192KHZ and 2048 buffer. George, K2CM Apalachin, NY -Original Message- From: NZ8J [mailto:n...@woh.rr.com] Sent: Tuesday, May 12, 2009 6:42 AM To: flexradio@flex-radio.biz Subject: [Flexradio] Sampling rate and buffers for CW operators? I'm trying to get a feel for what other primarily CW operators are using for sampling rate and buffers taking the computer limitations out of the equation. Assuming the computer is robust enough to handle it, what setting do you find the best overall balance between latency and filter sharpness? I'm using a Intel quad core with 4 GB ram and I have the firewire driver and primary audio set at 192Khz sampling rate and buffer size of 2048. (Firewire at "normal" operation) The DSP buffers are set at RX=4096 and TX=2048. There appears to be little difference between the 100hz and 25 hz filters at these settings. The CPU usage is normally less than 20% running PowerSDR 1.18.0 and Logic 8 under these settings I am just learning how to operate this radio and would like to see what other cw operators are using. I am amazed by how quiet the radio is and how much easier it is to copy weak cw signals down in the noise. Thanks Tim NZ8J ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Sampling rate and buffers for CW operators?
On May 12, 2009, at 3:57 AM, Bob McGwier wrote: On CW, you want to set the TX DSP buffer small. At 96000 samples per second. The DSP is not actually called AT ALL during transmit. We have thought a lot about doing that, but just haven't done it. The only reason for doing it is to get the display fired up with your keyed elements. I hope to end the question of filter shape and sample rate forever today. The multirate code is very close to deployment in the simplest form. Following this, filter shape factors will be IDENTICAL at 192000, 96000, and 48000 (at long last). Ah, at last. I recently switched to using a sample rate of 48KHz and sample buffers in order to get the best filter skirts and was bemoaning the loss of width on the pan display. You want to set the Audio buffers as small as is consistent with stability. I wish I could give you better guidance but this is really almost totally out of our control. It depends on your firewire, computer, .. I have a set of functions in mind on how to give advice on the settings for these modes or just doing it but allowing you to change it. I bet it would be possible for the software to determine how long it takes to process things and then set values accordingly. With a single downconversion stage, and its linearity, coupled with the (still) best audio A/D for under a $1000, it does sound beautiful. The lack of intermod in the audio does make for very pleasant listening. No kidding. It is why I tell people that the F5K is the best receiver I have ever heard, my other complaints notwithstanding. The raw material is there and no one beats it. The user features are now what need work. Automate things that can be automated. -- Brian Lloyd 3191 Western Drive brianl AT lloyd DOT com Cameron Park, CA 95682 +1.916.367.2131 (voice) +1.270.912.0788 (fax) PGP key ID: 12095C52A32A1B6C PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C -- 73 de Brian, WB6RQN/J79BPL Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Sampling rate and buffers for CW operators?
Hello Tim, I was just about to press the 'send' key on my email response when I saw Bob's email, and I'll second his comments and your comments about the sound of the receiver. It's a real pleasure to listen to. If you want to hear just how good the filters can be, try a sample rate of 48K, 512 for the audio buffer size, and 4096 DSP RX buffers. You will definitely observe a difference even between the 25 Hz and 50 Hz filters. It's my understanding that once Bob has implemented the multirate code, all sample rates will provide the same incredible filter performance as can be achieved currently with the 48K sample rate! I've been operating cw for 43 years, and I feel very confident in saying that you won't find a better performing or better sounding receiver - at any price. Have fun! 73, Dale WA8SRA NZ8J wrote: I'm trying to get a feel for what other primarily CW operators are using for sampling rate and buffers taking the computer limitations out of the equation. Assuming the computer is robust enough to handle it, what setting do you find the best overall balance between latency and filter sharpness? I'm using a Intel quad core with 4 GB ram and I have the firewire driver and primary audio set at 192Khz sampling rate and buffer size of 2048. (Firewire at "normal" operation) The DSP buffers are set at RX=4096 and TX=2048. There appears to be little difference between the 100hz and 25 hz filters at these settings. The CPU usage is normally less than 20% running PowerSDR 1.18.0 and Logic 8 under these settings I am just learning how to operate this radio and would like to see what other cw operators are using. I am amazed by how quiet the radio is and how much easier it is to copy weak cw signals down in the noise. Thanks Tim NZ8J ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Sampling rate and buffers for CW operators?
Tim, To get the sharpest RX (and for that matter, TX too) filters, currently you need to use the lowest sampling rate (48 KHz) and the largest DSP RX buffer size. This relationship is explained in great detail in the most current version of the FLEX Owner's Manual, appendix C. http://support.flex-radio.com/Downloads.aspx?id=271 -Tim -Original Message- From: flexradio-boun...@flex-radio.biz [mailto:flexradio-boun...@flex-radio.biz] On Behalf Of NZ8J Sent: Tuesday, May 12, 2009 6:42 AM To: flexradio@flex-radio.biz Subject: [SPAM] [Flexradio] Sampling rate and buffers for CW operators? I'm trying to get a feel for what other primarily CW operators are using for sampling rate and buffers taking the computer limitations out of the equation. Assuming the computer is robust enough to handle it, what setting do you find the best overall balance between latency and filter sharpness? I'm using a Intel quad core with 4 GB ram and I have the firewire driver and primary audio set at 192Khz sampling rate and buffer size of 2048. (Firewire at "normal" operation) The DSP buffers are set at RX=4096 and TX=2048. There appears to be little difference between the 100hz and 25 hz filters at these settings. The CPU usage is normally less than 20% running PowerSDR 1.18.0 and Logic 8 under these settings I am just learning how to operate this radio and would like to see what other cw operators are using. I am amazed by how quiet the radio is and how much easier it is to copy weak cw signals down in the noise. Thanks Tim NZ8J ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Sampling rate and buffers for CW operators?
On CW, you want to set the TX DSP buffer small. At 96000 samples per second. The DSP is not actually called AT ALL during transmit. We have thought a lot about doing that, but just haven't done it. The only reason for doing it is to get the display fired up with your keyed elements. I hope to end the question of filter shape and sample rate forever today. The multirate code is very close to deployment in the simplest form. Following this, filter shape factors will be IDENTICAL at 192000, 96000, and 48000 (at long last). You want to set the Audio buffers as small as is consistent with stability. I wish I could give you better guidance but this is really almost totally out of our control. It depends on your firewire, computer, .. I have a set of functions in mind on how to give advice on the settings for these modes or just doing it but allowing you to change it. With a single downconversion stage, and its linearity, coupled with the (still) best audio A/D for under a $1000, it does sound beautiful. The lack of intermod in the audio does make for very pleasant listening. Bob N4HY NZ8J wrote: I'm trying to get a feel for what other primarily CW operators are using for sampling rate and buffers taking the computer limitations out of the equation. Assuming the computer is robust enough to handle it, what setting do you find the best overall balance between latency and filter sharpness? I'm using a Intel quad core with 4 GB ram and I have the firewire driver and primary audio set at 192Khz sampling rate and buffer size of 2048. (Firewire at "normal" operation) The DSP buffers are set at RX=4096 and TX=2048. There appears to be little difference between the 100hz and 25 hz filters at these settings. The CPU usage is normally less than 20% running PowerSDR 1.18.0 and Logic 8 under these settings I am just learning how to operate this radio and would like to see what other cw operators are using. I am amazed by how quiet the radio is and how much easier it is to copy weak cw signals down in the noise. Thanks Tim NZ8J ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ -- (Co)Author: DttSP, Quiktrak, PowerSDR, GnuRadio Member: ARRL, AMSAT, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. "You don't need to see the whole staircase, just take the first step.", MLK. Twitter:rwmcgwier Active: Facebook,Myspace,LinkedIn ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
[Flexradio] Sampling rate and buffers for CW operators?
I'm trying to get a feel for what other primarily CW operators are using for sampling rate and buffers taking the computer limitations out of the equation. Assuming the computer is robust enough to handle it, what setting do you find the best overall balance between latency and filter sharpness? I'm using a Intel quad core with 4 GB ram and I have the firewire driver and primary audio set at 192Khz sampling rate and buffer size of 2048. (Firewire at "normal" operation) The DSP buffers are set at RX=4096 and TX=2048. There appears to be little difference between the 100hz and 25 hz filters at these settings. The CPU usage is normally less than 20% running PowerSDR 1.18.0 and Logic 8 under these settings I am just learning how to operate this radio and would like to see what other cw operators are using. I am amazed by how quiet the radio is and how much easier it is to copy weak cw signals down in the noise. Thanks Tim NZ8J ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
