# GNU Radio **URL:** https://www.ruby-forum.com/c/gnu-radio/15.md?page=67 [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:** 68 --- ## [Sampling time of AD and operation time of FPGA](https://www.ruby-forum.com/t/sampling-time-of-ad-and-operation-time-of-fpga/230344)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 0\ **Last updated:** [June 12, 2014, 3:21am UTC](https://www.ruby-forum.com/t/sampling-time-of-ad-and-operation-time-of-fpga/230344 "2014-06-12T03:21:05Z")
Hi! I am a student from China and I am studying the energy detection algorithm with USRP1 and RFX2400 on Gnuradio 3.3.0 and Ubuntu10.04. There is an index I want to know about the algorithm is Sensing Time including… --- ## [Pilot symbols in ofdm](https://www.ruby-forum.com/t/pilot-symbols-in-ofdm/230338)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 3\ **Last updated:** [June 11, 2014, 6:11pm UTC](https://www.ruby-forum.com/t/pilot-symbols-in-ofdm/230338 "2014-06-11T18:11:41Z")
Hi Looking at the ofdm receiver at ofdm\_rx grc, I see that schmidl and cox synchronisation algorithm uses sync1 and sync2 which are two ofdm training symbols that help in frequency offset correction and also timing … --- ## [How to use stream tags](https://www.ruby-forum.com/t/how-to-use-stream-tags/230335)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 0\ **Last updated:** [June 11, 2014, 10:06am UTC](https://www.ruby-forum.com/t/how-to-use-stream-tags/230335 "2014-06-11T10:06:23Z")
Hi there, I have used the gnuradio and usrp to implement a three nodes poll network and that works perfectly. Now I want to implement a tdma network. I notice the stream tag can be used to implement synchronization ,… --- ## [\[GSoC\] Co-Processors Update #2](https://www.ruby-forum.com/t/gsoc-co-processors-update-2/230330)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 0\ **Last updated:** [June 11, 2014, 6:17am UTC](https://www.ruby-forum.com/t/gsoc-co-processors-update-2/230330 "2014-06-11T06:17:22Z")
Hello all, Logistical Updates: Board arrived last Thursday Progress Updates: GR. Most of last week was spent digging through gnuradio-runtime to understand where we can modify things to allow direct buffer manip… --- ## [Re: tx\_time tag accuraccy](https://www.ruby-forum.com/t/re-tx-time-tag-accuraccy/230328)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 0\ **Last updated:** [June 11, 2014, 5:26am UTC](https://www.ruby-forum.com/t/re-tx-time-tag-accuraccy/230328 "2014-06-11T05:26:36Z")
On 06/09/2014 06:05 AM, bob wole wrote: Can I have a comment on it? Bob, we’ve given you a lot of information on this (see Tom’s posts as a start). If you still have questions, I recommend you start a new thread … --- ## [Time Limit](https://www.ruby-forum.com/t/time-limit/230317)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 1\ **Last updated:** [June 11, 2014, 12:17am UTC](https://www.ruby-forum.com/t/time-limit/230317 "2014-06-11T00:17:51Z")
Dear GNURadio fellows, I am trying to save my samples in a file for limited time or limited number of samples using file sink block in GRC. I have searched over archive and web, but I did not find how to do it. Ther… --- ## [FFSK\_Demod question](https://www.ruby-forum.com/t/ffsk-demod-question/230326)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 0\ **Last updated:** [June 10, 2014, 7:51pm UTC](https://www.ruby-forum.com/t/ffsk-demod-question/230326 "2014-06-10T19:51:42Z")
Hello everyone, I have a RTL file modulated by FFSK. However, I could not find any FFSK demod block from GNU Radio. Can I just use a GMSK one and later change the magnitude? Or is there any other way to demodulate tha… --- ## [Ver 3.7 stable?](https://www.ruby-forum.com/t/ver-3-7-stable/230269)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 3\ **Last updated:** [June 10, 2014, 2:27pm UTC](https://www.ruby-forum.com/t/ver-3-7-stable/230269 "2014-06-10T14:27:39Z")
Dear experts, (1) Introduction I am Mamoru Y. from Kyoto Univ. Some may know that I am doing satellite-beacon experiment by using USRP1 + GNU Radio. We call the receiver as GRBR (GNU Radio Beacon Receiver). http… --- ## [Error creating block with different input signature](https://www.ruby-forum.com/t/error-creating-block-with-different-input-signature/230282)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 2\ **Last updated:** [June 10, 2014, 2:15pm UTC](https://www.ruby-forum.com/t/error-creating-block-with-different-input-signature/230282 "2014-06-10T14:15:50Z")
Hi, I am trying to create a C++ block with different input signatures in each of the inputs.I tried the following 2 methods. I followed the example in “pfb\_clock\_sync\_ccf” and created the io signature as: static i… --- ## [Re: tx\_time tag accuraccy](https://www.ruby-forum.com/t/re-tx-time-tag-accuraccy/230289)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 1\ **Last updated:** [June 10, 2014, 2:14pm UTC](https://www.ruby-forum.com/t/re-tx-time-tag-accuraccy/230289 "2014-06-10T14:14:38Z")
Can I have a comment on it? – Bob --- ## [CMake error](https://www.ruby-forum.com/t/cmake-error/230312)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 1\ **Last updated:** [June 10, 2014, 11:47am UTC](https://www.ruby-forum.com/t/cmake-error/230312 "2014-06-10T11:47:59Z")
Hi I got the following error while doing the building out-of-tree module example given in “http://gnuradio.org/redmine/projects/gnuradio/wiki/NewTutorials3”. ttl@ttl-HP-Z220-CMT-Workstation:~/Documents/sreena/gr-tuto… --- ## [How to use a single-threaded scheduler](https://www.ruby-forum.com/t/how-to-use-a-single-threaded-scheduler/240171)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 6\ **Last updated:** [June 10, 2014, 11:40am UTC](https://www.ruby-forum.com/t/how-to-use-a-single-threaded-scheduler/240171 "2014-06-10T11:40:18Z")
Discuss-gnuradio mailing list removed\_email\_address@domain.invalid https://lists.gnu.org/mailman/listinfo/discuss-gnuradio --- ## [Clock block slow in position satellite calculation](https://www.ruby-forum.com/t/clock-block-slow-in-position-satellite-calculation/230311)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 1\ **Last updated:** [June 10, 2014, 9:53am UTC](https://www.ruby-forum.com/t/clock-block-slow-in-position-satellite-calculation/230311 "2014-06-10T09:53:22Z")
Hello, I have this flowgraph in GNURadio: → Green: calculates the signal delay of a satellite. → Yellow: a clock with a second precision. If I run the clock separately I can see… --- ## [Post\_guard and pre\_guard in Pecog implementation](https://www.ruby-forum.com/t/post-guard-and-pre-guard-in-pecog-implementation/230270)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 1\ **Last updated:** [June 10, 2014, 3:57am UTC](https://www.ruby-forum.com/t/post-guard-and-pre-guard-in-pecog-implementation/230270 "2014-06-10T03:57:44Z")
I was revisiting my previous work on FHSS based CR test bed setup designed using GRAS. I could not appreciably acknowledge the use of post\_gurad and pre\_guard in FHSS implementation of Pre-Cog. Could some one expl… --- ## [Re: tx\_time tag accuraccy](https://www.ruby-forum.com/t/re-tx-time-tag-accuraccy/230210)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 5\ **Last updated:** [June 9, 2014, 4:23pm UTC](https://www.ruby-forum.com/t/re-tx-time-tag-accuraccy/230210 "2014-06-09T16:23:27Z")
Marcus! Thanks for you comment. I think that USRP transmit FIFO is at the start of the DSP chain in FPGA i.e it is prior to both of the interpolation filters? right? I am not talking about when the burst will be over… --- ## [Writing wav file in GMSK TX, RX](https://www.ruby-forum.com/t/writing-wav-file-in-gmsk-tx-rx/230290)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 5\ **Last updated:** [June 9, 2014, 9:50am UTC](https://www.ruby-forum.com/t/writing-wav-file-in-gmsk-tx-rx/230290 "2014-06-09T09:50:45Z")
Hello list, I am simulating Voice transmission system in GRC using ‘GMSK Mod’, ‘GMSK Demod’ in loop without any channel in between & My flow graph configuration is as follows: Wav file source → Throttle → Packet enc… --- ## [Re: Scheduling a block even with no input items RE: Flow graph blocking when doing 2x1 transmission](https://www.ruby-forum.com/t/re-scheduling-a-block-even-with-no-input-items-re-flow-graph-blocking-when-doing-2x1-transmission/230223)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 1\ **Last updated:** [June 8, 2014, 7:26am UTC](https://www.ruby-forum.com/t/re-scheduling-a-block-even-with-no-input-items-re-flow-graph-blocking-when-doing-2x1-transmission/230223 "2014-06-08T07:26:07Z")
\-------- Original message -------- From: Activecat Date:2014/06/05 7:57 AM (GMT+00:00) To: David Halls ,removed\_email\_address@domain.invalid Subject: Re: \[Discuss-gnuradio\] Scheduling a block even with no input item… --- ## [Adding Accessor Methods in GR 3.7](https://www.ruby-forum.com/t/adding-accessor-methods-in-gr-3-7/230258)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 7\ **Last updated:** [June 6, 2014, 10:03pm UTC](https://www.ruby-forum.com/t/adding-accessor-methods-in-gr-3-7/230258 "2014-06-06T22:03:39Z")
I’ve recently converted to GR 3.7, and am currently on 3.7.3. I have created and run a new block in C++, but now want to add an accessor method to the block’s class. I defined it in \\_impl.h , in the p… --- ## [Re: GPSDO detection in B200](https://www.ruby-forum.com/t/re-gpsdo-detection-in-b200/230261)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 1\ **Last updated:** [June 6, 2014, 9:03pm UTC](https://www.ruby-forum.com/t/re-gpsdo-detection-in-b200/230261 "2014-06-06T21:03:33Z")
Is 1PPS used if I have GPSDO installed or does the B200 assume that 10MHz is already good enough? --- ## [Getting error: prototype for does not match any in class](https://www.ruby-forum.com/t/getting-error-prototype-for-does-not-match-any-in-class/230257)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 1\ **Last updated:** [June 6, 2014, 8:37pm UTC](https://www.ruby-forum.com/t/getting-error-prototype-for-does-not-match-any-in-class/230257 "2014-06-06T20:37:38Z")
Hello, I am writing my own signal processing block to calculate |x1|^2+|x2|^2 where x1 and x2 are complex. But I am getting below error \[ 5%\] Building CXX object lib/CMakeFiles/gnuradio-testmodule.dir/power2\_cf\_impl… --- ## [GPSDO detection in B200](https://www.ruby-forum.com/t/gpsdo-detection-in-b200/230259)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 1\ **Last updated:** [June 6, 2014, 8:22pm UTC](https://www.ruby-forum.com/t/gpsdo-detection-in-b200/230259 "2014-06-06T20:22:53Z")
Hi, How is the detection of GPSDO done in B200 ? I see that UHD tries to detect GPSDO every time I use B200 but what is it looking for? How to force switching between internal, external and GPSDO clock ? I have GPSDO… --- ## [Help with gr-trellis](https://www.ruby-forum.com/t/help-with-gr-trellis/230242)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 1\ **Last updated:** [June 6, 2014, 5:38pm UTC](https://www.ruby-forum.com/t/help-with-gr-trellis/230242 "2014-06-06T17:38:29Z")
Hello Everyone, To test my code, I am porting gnuradio/gr-trellis/examples/python/test\_tcm.py to c++, and encountering an error with the trellis fsm constructor. I tried creating an fsm object: const char\* fsm\_filen… --- ## [Calling functions from flowgraph?](https://www.ruby-forum.com/t/calling-functions-from-flowgraph/230225)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 5\ **Last updated:** [June 6, 2014, 11:17am UTC](https://www.ruby-forum.com/t/calling-functions-from-flowgraph/230225 "2014-06-06T11:17:47Z")
Hi everybody, well,I had a python script which works with gnuradio and outputs results on the terminal.To make it more visual,I made all the blocks on the gnuradio-comapnion but now I would like to output the results… --- ## [Failed to install gcc and make on usrp e110](https://www.ruby-forum.com/t/failed-to-install-gcc-and-make-on-usrp-e110/230224)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 1\ **Last updated:** [June 6, 2014, 8:01am UTC](https://www.ruby-forum.com/t/failed-to-install-gcc-and-make-on-usrp-e110/230224 "2014-06-06T08:01:36Z")
Hi, I tried to install gnuradio-companion on usrp e110 via the FAQ: http://code.ettus.com/redmine/ettus/projects/usrpe1xx/wiki/FAQ#How-do-I-install-GNU-Radio-from-source I made swap memory with a pen drive. But I stil… --- ## [Scheduling a block even with no input items RE: Flow graph blocking when doing 2x1 transmission](https://www.ruby-forum.com/t/scheduling-a-block-even-with-no-input-items-re-flow-graph-blocking-when-doing-2x1-transmission/230175)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 7\ **Last updated:** [June 6, 2014, 4:48am UTC](https://www.ruby-forum.com/t/scheduling-a-block-even-with-no-input-items-re-flow-graph-blocking-when-doing-2x1-transmission/230175 "2014-06-06T04:48:19Z")
Dear All, Had anyone tried to implementing a gnuradio block that will output zeros if there are no items at the input, and will simply copy the input to output otherwise? I find that if there are no items at the inpu… --- ## [Frequency Counter‏](https://www.ruby-forum.com/t/frequency-counter/240889)
**Author:** [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Replies:** 7\ **Last updated:** [June 6, 2014, 4:46am UTC](https://www.ruby-forum.com/t/frequency-counter/240889 "2014-06-06T04:46:33Z")
Hi list, Has anyone been able to implement a frequency counter yet? Any ideas on how I should try it? --- ## [DPKS Demodulator implementation (FIR)](https://www.ruby-forum.com/t/dpks-demodulator-implementation-fir/230239)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 0\ **Last updated:** [June 5, 2014, 8:22pm UTC](https://www.ruby-forum.com/t/dpks-demodulator-implementation-fir/230239 "2014-06-05T20:22:47Z")
I am interested in the implementation of the DPSK demodulator block in GNU radio. I have been profiling and debugging code to better understand the implementation of this block. One thing I noticed is that all of the … --- ## [Gnuradio/gr-digital/python/digital/ofdm\_receiver.py](https://www.ruby-forum.com/t/gnuradio-gr-digital-python-digital-ofdm-receiver-py/230229)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 3\ **Last updated:** [June 5, 2014, 6:33pm UTC](https://www.ruby-forum.com/t/gnuradio-gr-digital-python-digital-ofdm-receiver-py/230229 "2014-06-05T18:33:42Z")
Hi all: Thank you in advance. Version of gnuradio:3.7.4 I have read the gnuradio/gr-digital/python/digital/ofdm\_receiver.py,and i see: self.connect(self, self.chan\_filt) filter the input channel self.connect(se… --- ## [BER calculation in Packet data transmission](https://www.ruby-forum.com/t/ber-calculation-in-packet-data-transmission/230231)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 0\ **Last updated:** [June 5, 2014, 4:00pm UTC](https://www.ruby-forum.com/t/ber-calculation-in-packet-data-transmission/230231 "2014-06-05T16:00:43Z")
I am trying to execute tx\_ofdm.grc, rx\_ofdm.grc files (available in default in ) with BER block. But I am not getting any value on Number sink used for BER value. Is there any alternative to calculate the BER for pack… --- ## [Signal level](https://www.ruby-forum.com/t/signal-level/230215)
**Author:** [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Replies:** 9\ **Last updated:** [June 5, 2014, 2:23pm UTC](https://www.ruby-forum.com/t/signal-level/230215 "2014-06-05T14:23:37Z")
Hi, In GRC is it necessary that we give a signal to any sink having an amplitude greater than 1? Regards, Ali [Previous page](https://www.ruby-forum.com/c/gnu-radio/15.md?page=66) [Next page](https://www.ruby-forum.com/c/gnu-radio/15.md?page=68)