# GNU Radio **URL:** https://www.ruby-forum.com/c/gnu-radio/15.md?page=21 [Latest](https://www.ruby-forum.com/latest.md) · [Categories](https://www.ruby-forum.com/categories.md) · [Tags](https://www.ruby-forum.com/tags.md) **Page:** 22 --- ## [Alsa problem](https://www.ruby-forum.com/t/alsa-problem/242079)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 1\ **Last updated:** [May 25, 2015, 5:07pm UTC](https://www.ruby-forum.com/t/alsa-problem/242079 "2015-05-25T17:07:21Z")
Hi together, i am using grc 3.7.6.1. The system is odroid with ubuntu 14. I tested the alsa system with aplay and the sound works. When i start my project on odroid i get the following error message. On my desktop p… --- ## [Re: How to "declare\_sample\_delay" in C++?](https://www.ruby-forum.com/t/re-how-to-declare-sample-delay-in-c/242080)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 0\ **Last updated:** [May 25, 2015, 2:06pm UTC](https://www.ruby-forum.com/t/re-how-to-declare-sample-delay-in-c/242080 "2015-05-25T14:06:15Z")
Hi Martin, Thanks for the answer. My confusion is that when you generate, for example, a multi-stage polyphase decimator in GRC, a ‘declare\_sample\_delay(0)’ code will be generated for each decimation block. When I g… --- ## [Grc - libGL error: failed to load driver: i965](https://www.ruby-forum.com/t/grc-libgl-error-failed-to-load-driver-i965/241981)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 1\ **Last updated:** [May 25, 2015, 12:26pm UTC](https://www.ruby-forum.com/t/grc-libgl-error-failed-to-load-driver-i965/241981 "2015-05-25T12:26:22Z")
Discuss-gnuradio mailing list removed\_email\_address@domain.invalid https://lists.gnu.org/mailman/listinfo/discuss-gnuradio --- ## [Parameters for Source Block](https://www.ruby-forum.com/t/parameters-for-source-block/242072)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 0\ **Last updated:** [May 25, 2015, 2:05am UTC](https://www.ruby-forum.com/t/parameters-for-source-block/242072 "2015-05-25T02:05:58Z")
Got the source block working. Thanks for the help. Is there a standard way to add parameters to a source block? I notice in gnuradio-companion you can right click on the block and it has parameters that are settable … --- ## [How to install RTL-SDR driver in debian jessie](https://www.ruby-forum.com/t/how-to-install-rtl-sdr-driver-in-debian-jessie/242042)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 1\ **Last updated:** [May 24, 2015, 7:57pm UTC](https://www.ruby-forum.com/t/how-to-install-rtl-sdr-driver-in-debian-jessie/242042 "2015-05-24T19:57:56Z")
Hello I installed GNURadio in the Hummingboard which has debian jessie OS. But the system cannot detect RTL-SDR. When I type command lsusb, it show Realtek Semiconductor Corp. RTL2838 DVB-T. when I type lsmod, noth… --- ## [An ISDB-T receiver implementation](https://www.ruby-forum.com/t/an-isdb-t-receiver-implementation/242041)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 1\ **Last updated:** [May 24, 2015, 7:56pm UTC](https://www.ruby-forum.com/t/an-isdb-t-receiver-implementation/242041 "2015-05-24T19:56:11Z")
Hi everybody, Some months ago we started working on an ISDB-T receiver for GNU Radio. We have reached a point at which it may be useful for other people, so we decided to announce to it on the list. The sources may b… --- ## [Is it possible to undo my mistake](https://www.ruby-forum.com/t/is-it-possible-to-undo-my-mistake/241739)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 10\ **Last updated:** [May 24, 2015, 6:44pm UTC](https://www.ruby-forum.com/t/is-it-possible-to-undo-my-mistake/241739 "2015-05-24T18:44:54Z")
Dear all, I followed a tutorial online to install a sdr software and accidentaly deleted files from my gnuradio installation. It took me a very long time to manage to set up everyting so before I start from the begin… --- ## [Need of delay=58 in the PSK Symbol Recovery Guided Tutorial](https://www.ruby-forum.com/t/need-of-delay-58-in-the-psk-symbol-recovery-guided-tutorial/242056)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 6\ **Last updated:** [May 23, 2015, 4:44pm UTC](https://www.ruby-forum.com/t/need-of-delay-58-in-the-psk-symbol-recovery-guided-tutorial/242056 "2015-05-23T16:44:00Z")
Hi, I managed to successfully replicate the results of this tutorial: https://gnuradio.org/redmine/projects/gnuradio/wiki/Guided\_Tutorial\_PSK\_Demodulation and, of course I understand the reason for a delay between the … --- ## [Playback file on multiple frequencies](https://www.ruby-forum.com/t/playback-file-on-multiple-frequencies/242057)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 0\ **Last updated:** [May 23, 2015, 4:41pm UTC](https://www.ruby-forum.com/t/playback-file-on-multiple-frequencies/242057 "2015-05-23T16:41:13Z")
Hi everyone. I have a single channel radio (USRP N210) that I am trying to playback a file on multiple frequencies with. I assume a need a sort of channelizer function but am having difficulty implementing this. Bas… --- ## [GNU Radio IIR Filter Taps](https://www.ruby-forum.com/t/gnu-radio-iir-filter-taps/242049)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 4\ **Last updated:** [May 22, 2015, 10:46pm UTC](https://www.ruby-forum.com/t/gnu-radio-iir-filter-taps/242049 "2015-05-22T22:46:13Z")
Hello, I’ve been trying to move the fm De-emphasis (an IIR filter, I’m pretty sure) functionality of the WBFM\_Receive block into an FPGA, and I’m a little confused as to how the taps work. I’m in fm\_emph.py and can s… --- ## [Basic theory of IIR filters](https://www.ruby-forum.com/t/basic-theory-of-iir-filters/242055)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 0\ **Last updated:** [May 22, 2015, 9:21pm UTC](https://www.ruby-forum.com/t/basic-theory-of-iir-filters/242055 "2015-05-22T21:21:30Z")
I’ve switch back with filters, and I’d like to implement a IIR filters,also because I’ve seen that there are different papers about IIR filters in CUDA,but I didn’t see any implementation. I’ve see that actually gnur… --- ## [How to "declare\_sample\_delay" in C++?](https://www.ruby-forum.com/t/how-to-declare-sample-delay-in-c/242053)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 1\ **Last updated:** [May 22, 2015, 9:01pm UTC](https://www.ruby-forum.com/t/how-to-declare-sample-delay-in-c/242053 "2015-05-22T21:01:39Z")
Hi list, I am doing some (polyphase) decimation with GNURadio in C++. I constructed my filters, I wrote some wrapper, and my script compiles perfectly. However, I am a bit unclear about “declare\_sample\_delay”. Assum… --- ## [OFDM Transmitter and Receiver - poor synchronization with USRP1](https://www.ruby-forum.com/t/ofdm-transmitter-and-receiver-poor-synchronization-with-usrp1/241901)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 7\ **Last updated:** [May 22, 2015, 8:21pm UTC](https://www.ruby-forum.com/t/ofdm-transmitter-and-receiver-poor-synchronization-with-usrp1/241901 "2015-05-22T20:21:55Z")
Hi, I am trying to implement OFDM transmitter and receiver (both in one flowgraph) using 2 USRP1s (both equipped with WBX). I have adjusted the signal so there’s no peak above 1 and -1, but I am still failing at sync… --- ## [BER performance of gmsk](https://www.ruby-forum.com/t/ber-performance-of-gmsk/242022)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 1\ **Last updated:** [May 22, 2015, 6:17am UTC](https://www.ruby-forum.com/t/ber-performance-of-gmsk/242022 "2015-05-22T06:17:10Z")
Hi everyone, I am testing the BER performance of the gmsk of GNURaido with two USRP, one as a transmitter, and another as a receiver. I find that the error bits would cause the subsequent bits getting error. The re… --- ## [Multiplicative constant vector for multiply\_const\_vcc](https://www.ruby-forum.com/t/multiplicative-constant-vector-for-multiply-const-vcc/242031)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 1\ **Last updated:** [May 22, 2015, 12:46am UTC](https://www.ruby-forum.com/t/multiplicative-constant-vector-for-multiply-const-vcc/242031 "2015-05-22T00:46:31Z")
Hi, What is the proper way to set-up the multiplicative constant vector for multiply\_const\_vcc? I tried the code below and although it compiles, upon running the program I get the following error: Segmentation faul… --- ## [Missing GRC block panel](https://www.ruby-forum.com/t/missing-grc-block-panel/242040)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 0\ **Last updated:** [May 21, 2015, 6:26pm UTC](https://www.ruby-forum.com/t/missing-grc-block-panel/242040 "2015-05-21T18:26:47Z")
Hi all, did anybody experience missing complete blocks panel in GRC? 3.6.5.1. Thanx --- ## [UHD: Sink and source synchronization](https://www.ruby-forum.com/t/uhd-sink-and-source-synchronization/242035)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 1\ **Last updated:** [May 21, 2015, 6:16pm UTC](https://www.ruby-forum.com/t/uhd-sink-and-source-synchronization/242035 "2015-05-21T18:16:17Z")
Hi all, Right now I’m implementing tx and rx on the same device (USRP b210), and I’m trying to synchronize the two in order to determine the exact moment when a message is sent by the Tx. The purpose of this synchroni… --- ## [Installing pre-compiled OOTs](https://www.ruby-forum.com/t/installing-pre-compiled-oots/242021)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 3\ **Last updated:** [May 21, 2015, 7:47am UTC](https://www.ruby-forum.com/t/installing-pre-compiled-oots/242021 "2015-05-21T07:47:40Z")
Hello everyone, I come to you with a rather strange request :slight\_smile: I’m looking into the possibility of installing OOTs that were precompiled in one system onto another. Lets consider basic stuff first: Vers… --- ## [Which type of block do I use here?](https://www.ruby-forum.com/t/which-type-of-block-do-i-use-here/242008)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 3\ **Last updated:** [May 21, 2015, 4:01am UTC](https://www.ruby-forum.com/t/which-type-of-block-do-i-use-here/242008 "2015-05-21T04:01:30Z")
Hi Say I want to create an energy detect block that takes a certain number of input samples, measures the (signal) power and compares it against a threshold. Only if the power exceeds the threshold, the block has to … --- ## [Jammer with allowed frequency](https://www.ruby-forum.com/t/jammer-with-allowed-frequency/242028)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 0\ **Last updated:** [May 21, 2015, 2:42am UTC](https://www.ruby-forum.com/t/jammer-with-allowed-frequency/242028 "2015-05-21T02:42:06Z")
Hi guys, anyone have ideas how to implement next scenario: I need to RX signal on freq 150 Mhz +200 khz but need to jam all signal around this freq, means from 145 Mhz to 150 Mhz and from 150.2 Mhz to 155 Mhz should … --- ## [Meet GNU Radio developers at the Wireless@VT Symposium](https://www.ruby-forum.com/t/meet-gnu-radio-developers-at-the-wireless-vt-symposium/242019)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 0\ **Last updated:** [May 20, 2015, 7:02pm UTC](https://www.ruby-forum.com/t/meet-gnu-radio-developers-at-the-wireless-vt-symposium/242019 "2015-05-20T19:02:21Z")
There will be a number of GNU Radio developers at the Wireless@VT Symposium\[1\] next week. We are having a small reception at my house, near the Inn at VT. We’ll start gathering after 6PM on Tuesday, the evening before… --- ## [Re: Which blocks do you like?](https://www.ruby-forum.com/t/re-which-blocks-do-you-like/242017)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 0\ **Last updated:** [May 20, 2015, 7:00pm UTC](https://www.ruby-forum.com/t/re-which-blocks-do-you-like/242017 "2015-05-20T19:00:01Z")
Thank you for your replies!! I really appreciate them. If you want to give a look about my porting,here is possible to see something: https://github.com/m-ri/gr-CUDA Greetings, marco --- ## [Syncronising transmitting and receiving streams to and from a USRP](https://www.ruby-forum.com/t/syncronising-transmitting-and-receiving-streams-to-and-from-a-usrp/242001)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 1\ **Last updated:** [May 20, 2015, 6:56pm UTC](https://www.ruby-forum.com/t/syncronising-transmitting-and-receiving-streams-to-and-from-a-usrp/242001 "2015-05-20T18:56:30Z")
Hi All I’m using N210 USRP with XCVR2450 (Rev2) hardware. I’m writing an out of tree module for GRC in C++ for a consensus synchronisation system. The block takes in a certain number of samples from the USRP, then e… --- ## [Gr-modtool cpp generation issue](https://www.ruby-forum.com/t/gr-modtool-cpp-generation-issue/242007)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 2\ **Last updated:** [May 20, 2015, 6:16pm UTC](https://www.ruby-forum.com/t/gr-modtool-cpp-generation-issue/242007 "2015-05-20T18:16:47Z")
I am in the process of converting some 3.6 modules to 3.7. So I am generating new modules then adding the code from the old modules. I have one module that takes a filename as a parameter so it is declared like this … --- ## [Update the firmware and FPGA images for your device](https://www.ruby-forum.com/t/update-the-firmware-and-fpga-images-for-your-device/242018)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 0\ **Last updated:** [May 20, 2015, 2:44pm UTC](https://www.ruby-forum.com/t/update-the-firmware-and-fpga-images-for-your-device/242018 "2015-05-20T14:44:44Z")
hi i am use ubuntu 14.04 and install gnuradio with this command wget http://www.sbrac.org/files/build-gnuradio && chmod a+x ./build-gnuradio && ./build-gnuradio when i try to test uhd\_usrp\_probe user@userr-X455LDB:~$… --- ## [Using fft::fft\_complex in an out-of-tree moudle](https://www.ruby-forum.com/t/using-fft-fft-complex-in-an-out-of-tree-moudle/242006)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 2\ **Last updated:** [May 20, 2015, 6:18am UTC](https://www.ruby-forum.com/t/using-fft-fft-complex-in-an-out-of-tree-moudle/242006 "2015-05-20T06:18:15Z")
Hi all, I created an out-of-tree module for my personal project. In one block, I need to perform FFT and IFFF, so I put “#include \” in the header file, and then declare \*fft::fft\_complex d\_ifft; … --- ## [Which blocks do you like?](https://www.ruby-forum.com/t/which-blocks-do-you-like/241968)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 4\ **Last updated:** [May 19, 2015, 4:59pm UTC](https://www.ruby-forum.com/t/which-blocks-do-you-like/241968 "2015-05-19T16:59:04Z")
Hi, for my thesis I’m making “porting” of gnuradio blocks over CUDA… For the moment,I’ve bring basick blocks,FIR filter,FFT,an FM receiver(not so good due to latency) and I’m working with ofdm…I still need to implem… --- ## [Sample and Hold](https://www.ruby-forum.com/t/sample-and-hold/241998)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 0\ **Last updated:** [May 19, 2015, 3:48pm UTC](https://www.ruby-forum.com/t/sample-and-hold/241998 "2015-05-19T15:48:29Z")
Hey, guys. Plase, can anyone say how to use the “sample and hold” block? Which block do I have to use to connect to its control input? Thanks a lot. --- ## [Accessing Filter Kernels in Python](https://www.ruby-forum.com/t/accessing-filter-kernels-in-python/241992)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 1\ **Last updated:** [May 19, 2015, 3:30pm UTC](https://www.ruby-forum.com/t/accessing-filter-kernels-in-python/241992 "2015-05-19T15:30:16Z")
Hello, I am looking for help in using the filter kernels in python. In particular, I want to use the filter.kernel.fir\_filter\_fff. Is this even possible? I have poked around quite a bit and have not been able to fi… --- ## [UHD: undefined symbol uhd\_time\_spec\_t](https://www.ruby-forum.com/t/uhd-undefined-symbol-uhd-time-spec-t/241994)
**Author:** [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Replies:** 2\ **Last updated:** [May 19, 2015, 11:53am UTC](https://www.ruby-forum.com/t/uhd-undefined-symbol-uhd-time-spec-t/241994 "2015-05-19T11:53:28Z")
Hi all, I’m having right now problems with a implementation of a time tag in a block that I’m writing. I’m basically writing a burst tagger with SOB, EOB and TX\_TIME tags. The first two are working, but the third (th… [Previous page](https://www.ruby-forum.com/c/gnu-radio/15.md?page=20) [Next page](https://www.ruby-forum.com/c/gnu-radio/15.md?page=22)