Re: [Discuss-gnuradio] appending preamble with different power
I'm a bit confused. What exactly are you trying to do? On Thu, Jun 23, 2011 at 9:17 AM, Songsong Gee gee.songs...@gmail.comwrote: Continueing with http://www.ruby-forum.com/topic/1983866, I have planned to append a preamble before an actual signal and turn RX on earlier than TX. Then RX will receive a signal like below: |---RX turn on--|---TX turn on- (---trash signal---)(---preamble---)(---actual signal---) And this signal is demodulated and stored into a sink file. After that, I run a program that extracts an actual data only and compare it to the original. My concern is that this preamble should be assumed to be perfect i.e. no errors Of course, there isn't no error. However if I set an amplitude to maximum value, it can be said to be no error. I have a pre-defined preamble sequence with length n (n = around 100-200, can be changed) Thus, I am trying to change amplitude of modulated signal for preamble and actual signal But I have problem with some quadrature modulation. Flow graphs are in below: http://dl.dropbox.com/u/11382666/for_gnuradio_mailinglist/M-DPSK.png http://dl.dropbox.com/u/11382666/for_gnuradio_mailinglist/M-FSK.png My question is that, how many samples after DPSK mod or frequency mod block corresponds to each sample from file source? I have to solve this problem in order to figure out how many samples are generated from preamble with length n. If I know that information, I can set a duration for Multiply const block having large value for preamble and normal value for actual signal And second question is that, although I know that information, I don't know how I can control value. For example, preamble with length 200, then I want to set large value for duration 200 * x (number of samples generated after DPSK, Frequency mod), and after that I want to set normal value for remaining duration. Is it too complex for gnuradio-companion flow graph to make? And is python hard coding possible? -- Seokseong Jeon (aka Songsong Gee) ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] appending preamble with different power
On Fri, 2011-06-24 at 01:17 +0900, Songsong Gee wrote: Continueing with http://www.ruby-forum.com/topic/1983866, I have planned to append a preamble before an actual signal and turn RX on earlier than TX. Then RX will receive a signal like below: |---RX turn on--|---TX turn on- (---trash signal---)(---preamble---)(---actual signal---) And this signal is demodulated and stored into a sink file. After that, I run a program that extracts an actual data only and compare it to the original. My concern is that this preamble should be assumed to be perfect i.e. no errors Of course, there isn't no error. However if I set an amplitude to maximum value, it can be said to be no error. I don't understand what you mean here. You can find an imperfect preamble sequence using a correlator. I have a pre-defined preamble sequence with length n (n = around 100-200, can be changed) Thus, I am trying to change amplitude of modulated signal for preamble and actual signal But I have problem with some quadrature modulation. Flow graphs are in below: http://dl.dropbox.com/u/11382666/for_gnuradio_mailinglist/M-DPSK.png http://dl.dropbox.com/u/11382666/for_gnuradio_mailinglist/M-FSK.png My question is that, how many samples after DPSK mod or frequency mod block corresponds to each sample from file source? It's right there in the block, where it says samples/symbol. I have to solve this problem in order to figure out how many samples are generated from preamble with length n. If I know that information, I can set a duration for Multiply const block having large value for preamble and normal value for actual signal Why would you set the amplitude of the preamble differently than the actual data? --n And second question is that, although I know that information, I don't know how I can control value. For example, preamble with length 200, then I want to set large value for duration 200 * x (number of samples generated after DPSK, Frequency mod), and after that I want to set normal value for remaining duration. Is it too complex for gnuradio-companion flow graph to make? And is python hard coding possible? -- Seokseong Jeon (aka Songsong Gee) ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] appending preamble with different power
On 23/06/2011 2:31 PM, Nick Foster wrote: Why would you set the amplitude of the preamble differently than the actual data? --n In the hopelessly-naive assumption that the preamble can be made to be perfect through brute-force transmit power. Like you observed earlier, correlation is the correct way to detect a preamble. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] appending preamble with different power
Ok. First of all, I'd like to run a code like below (pseudo): for i = 1 to 200 // preamble duration amp = 32767 end for amp = 100 Next, how many baseband samples are generated by DPSK or Frequency mod block for a single symbol input Composed with Android (Galaxys) 2011. 6. 24. 오전 3:31에 Nick Foster n...@ettus.com님이 작성: On Fri, 2011-06-24 at 01:17 +0900, Songsong Gee wrote: Continueing with http://www.ruby-forum.com/topic/1983866, I have planned to append a preamble before an actual signal and turn RX on earlier than TX. Then RX will receive a signal like below: |---RX turn on--|---TX turn on- (---trash signal---)(---preamble---)(---actual signal---) And this signal is demodulated and stored into a sink file. After that, I run a program that extracts an actual data only and compare it to the original. My concern is that this preamble should be assumed to be perfect i.e. no errors Of course, there isn't no error. However if I set an amplitude to maximum value, it can be said to be no error. I don't understand what you mean here. You can find an imperfect preamble sequence using a correlator. I have a pre-defined preamble sequence with length n (n = around 100-200, can be changed) Thus, I am trying to change amplitude of modulated signal for preamble and actual signal But I have problem with some quadrature modulation. Flow graphs are in below: http://dl.dropbox.com/u/11382666/for_gnuradio_mailinglist/M-DPSK.png http://dl.dropbox.com/u/11382666/for_gnuradio_mailinglist/M-FSK.png My question is that, how many samples after DPSK mod or frequency mod block corresponds to each sample from file source? It's right there in the block, where it says samples/symbol. I have to solve this problem in order to figure out how many samples are generated from preamble with length n. If I know that information, I can set a duration for Multiply const block having large value for preamble and normal value for actual signal Why would you set the amplitude of the preamble differently than the actual data? --n And second question is that, although I know that information, I don't know how I can control value. For example, preamble with length 200, then I want to set large value for duration 200 * x (number of samples generated after DPSK, Frequency mod), and after that I want to set normal value for remaining duration. Is it too complex for gnuradio-companion flow graph to make? And is python hard coding possible? -- Seokseong Jeon (aka Songsong Gee) ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] appending preamble with different power
Or operate your receiver at absolute zero so there is no thermal noise? :D On a more serious note, how I do preamble detection is the following: * Figure out the sample sequence of your TX'ed preamble sequence, use this as a match filter. * Tag the magnitude of the match filter and run through the peak detector block, which should locate the spike in energy from the preamble. * When this happens, your packet frame begins one sample in the future (post preamble). From me, this seems to work pretty wellall things considered. On Thu, Jun 23, 2011 at 11:48 AM, Marcus D. Leech mle...@ripnet.com wrote: On 23/06/2011 2:31 PM, Nick Foster wrote: Why would you set the amplitude of the preamble differently than the actual data? --n In the hopelessly-naive assumption that the preamble can be made to be perfect through brute-force transmit power. Like you observed earlier, correlation is the correct way to detect a preamble. __**_ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/**listinfo/discuss-gnuradiohttps://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] appending preamble with different power
On Fri, 2011-06-24 at 04:00 +0900, Songsong Gee wrote: Ok. First of all, I'd like to run a code like below (pseudo): for i = 1 to 200 // preamble duration amp = 32767 end for amp = 100 Like I said earlier, this is unlikely to be a good approach to synchronizing with a preamble. Next, how many baseband samples are generated by DPSK or Frequency mod block for a single symbol input Did you read the email you just replied to? Composed with Android (Galaxys) 2011. 6. 24. 오전 3:31에 Nick Foster n...@ettus.com님이 작성: On Fri, 2011-06-24 at 01:17 +0900, Songsong Gee wrote: Continueing with http://www.ruby-forum.com/topic/1983866, I have planned to append a preamble before an actual signal and turn RX on earlier than TX. Then RX will receive a signal like below: |---RX turn on--|---TX turn on- (---trash signal---)(---preamble---)(---actual signal---) And this signal is demodulated and stored into a sink file. After that, I run a program that extracts an actual data only and compare it to the original. My concern is that this preamble should be assumed to be perfect i.e. no errors Of course, there isn't no error. However if I set an amplitude to maximum value, it can be said to be no error. I don't understand what you mean here. You can find an imperfect preamble sequence using a correlator. I have a pre-defined preamble sequence with length n (n = around 100-200, can be changed) Thus, I am trying to change amplitude of modulated signal for preamble and actual signal But I have problem with some quadrature modulation. Flow graphs are in below: http://dl.dropbox.com/u/11382666/for_gnuradio_mailinglist/M-DPSK.png http://dl.dropbox.com/u/11382666/for_gnuradio_mailinglist/M-FSK.png My question is that, how many samples after DPSK mod or frequency mod block corresponds to each sample from file source? It's right there in the block, where it says samples/symbol. I have to solve this problem in order to figure out how many samples are generated from preamble with length n. If I know that information, I can set a duration for Multiply const block having large value for preamble and normal value for actual signal Why would you set the amplitude of the preamble differently than the actual data? --n And second question is that, although I know that information, I don't know how I can control value. For example, preamble with length 200, then I want to set large value for duration 200 * x (number of samples generated after DPSK, Frequency mod), and after that I want to set normal value for remaining duration. Is it too complex for gnuradio-companion flow graph to make? And is python hard coding possible? -- Seokseong Jeon (aka Songsong Gee) ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] appending preamble with different power
On 23/06/2011 3:03 PM, Colby Boyer wrote: Or operate your receiver at absolute zero so there is no thermal noise? :D Infinite SNR. Must have :-) ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] appending preamble with different power
Continueing with http://www.ruby-forum.com/topic/1983866, I have planned to append a preamble before an actual signal and turn RX on earlier than TX. Then RX will receive a signal like below: |---RX turn on--|---TX turn on- (---trash signal---)(---preamble---)(---actual signal---) And this signal is demodulated and stored into a sink file. After that, I run a program that extracts an actual data only and compare it to the original. My concern is that this preamble should be assumed to be perfect i.e. no errors Of course, there isn't no error. However if I set an amplitude to maximum value, it can be said to be no error. I have a pre-defined preamble sequence with length n (n = around 100-200, can be changed) Thus, I am trying to change amplitude of modulated signal for preamble and actual signal But I have problem with some quadrature modulation. Flow graphs are in below: http://dl.dropbox.com/u/11382666/for_gnuradio_mailinglist/M-DPSK.png http://dl.dropbox.com/u/11382666/for_gnuradio_mailinglist/M-FSK.png My question is that, how many samples after DPSK mod or frequency mod block corresponds to each sample from file source? I have to solve this problem in order to figure out how many samples are generated from preamble with length n. If I know that information, I can set a duration for Multiply const block having large value for preamble and normal value for actual signal And second question is that, although I know that information, I don't know how I can control value. For example, preamble with length 200, then I want to set large value for duration 200 * x (number of samples generated after DPSK, Frequency mod), and after that I want to set normal value for remaining duration. Is it too complex for gnuradio-companion flow graph to make? And is python hard coding possible? -- Seokseong Jeon (aka Songsong Gee) ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
