Try specifying a receive frequency of 1.575 GHz with hackrf_transfer and tell matlab your IF is 420 kHz. The sum of the two frequencies is 1.57542 GHz, which is the L1 GPS frequency.
On Thu, Nov 19, 2015 at 2:44 PM, mourad ghafiri <[email protected]> wrote: > even I need the IF it in the matlab project :) , so what value I should > put there, I will experiment the hackrf_transfer program and see to what > extent I will get the desired results.. and for sure I will share my > results with you and for the hackrf community as a contribution for GPS > signal decoding, if I do it myself :) > > On Thu, Nov 19, 2015 at 10:40 PM, Karl Koscher <[email protected] > > wrote: > >> Just specify the frequency you want to tune to with -f. You shouldn't >> need to specify -i. >> >> On Thu, Nov 19, 2015 at 2:29 PM, mourad ghafiri <[email protected] >> > wrote: >> >>> @Karl Koscher >>> >>> I used the Gnu radio, I will use the hackrf_transfer , but please would >>> you help for IF parameter >>> [-i if_freq_hz] # Intermediate Frequency (IF) in Hz [2150MHz to 2750MHz] >>> ? >>> >>> I don't know what to set for IF since I need to tune hackrf at 1.575 GHz >>> and Bandwidth of 2 MHz and a sampling rate > 2*2 MHz >>> >>> would you give me a complete command for these requirements, >>> >>> Thank you so much in advance >>> >>> Regards; >>> >>> >>> On Thu, Nov 19, 2015 at 10:22 PM, Karl Koscher < >>> [email protected]> wrote: >>> >>>> How doesn't it work? You should probably just use the hackrf_transfer >>>> program to record data from the HackRF. By default, it stores data in >>>> complex int8 format. >>>> >>>> On Thu, Nov 19, 2015 at 2:18 PM, mourad ghafiri < >>>> [email protected]> wrote: >>>> >>>>> @Karl Koscher >>>>> >>>>> unfortunately the approach doesn't function well... please any hint to >>>>> achieve that goal which is: >>>>> >>>>> having an GPS L1 signal streaming for post processing with >>>>> matlab/octave ? we have HackRF and a GPS L1 antenna ... but we don't have >>>>> enough knowledge in hardware side, but we do know how to manipulate a file >>>>> streaming with float or int8 matrix data in Matlab/octave. >>>>> >>>>> Yours Sincerely; >>>>> >>>>> On Thu, Nov 19, 2015 at 10:11 PM, mourad ghafiri < >>>>> [email protected]> wrote: >>>>> >>>>>> @David Brown >>>>>> >>>>>> I appreciate your interaction with that basic question, in fact we >>>>>> are recording a L1 GPS streaming for post processing in a Matlab project >>>>>> for GPS positioning... so all we need simply is a file that contain an >>>>>> int8 >>>>>> type record. >>>>>> >>>>>> @Karl Koscher >>>>>> >>>>>> thank you so much, I will try this blocks Immediately and get back to >>>>>> you; if you still have time to complete this friendly (hackerfly :) ) >>>>>> conversation. >>>>>> >>>>>> On Thu, Nov 19, 2015 at 10:04 PM, Karl Koscher < >>>>>> [email protected]> wrote: >>>>>> >>>>>>> Use a Complex to Float/Real and Float to Char type converter block >>>>>>> between the HackRF source block and the file sink, and then change the >>>>>>> file >>>>>>> sync type to char. Or you can use the hackrf_transfer program and avoid >>>>>>> these conversions altogether. >>>>>>> >>>>>>> On Thu, Nov 19, 2015 at 1:49 PM, mourad ghafiri < >>>>>>> [email protected]> wrote: >>>>>>> >>>>>>>> thank you for your quick answer, please how to record the >>>>>>>> streaming in int8 type >>>>>>>> >>>>>>>> Regards; >>>>>>>> >>>>>>>> On Thu, Nov 19, 2015 at 9:40 PM, Karl Koscher < >>>>>>>> [email protected]> wrote: >>>>>>>> >>>>>>>>> You are recording complex floats. The intermediate frequency is >>>>>>>>> your frequency of interest minus what the HackRF is tuned to. If your >>>>>>>>> HackRF is tuned to 1.575 GHz but you want to decode the GPS L1 >>>>>>>>> signal, then >>>>>>>>> your IF is 420 kHz. >>>>>>>>> >>>>>>>>> On Thu, Nov 19, 2015 at 1:36 PM, mourad ghafiri < >>>>>>>>> [email protected]> wrote: >>>>>>>>> >>>>>>>>>> I attached the flow graph for the recording as well as a real >>>>>>>>>> time spectrum , I'm not sure what blocks to use or what parameters >>>>>>>>>> to set >>>>>>>>>> for this block in order to have the right streaming. >>>>>>>>>> thanks for showing interest to the question >>>>>>>>>> >>>>>>>>>> On Thu, Nov 19, 2015 at 9:16 PM, Karl Koscher < >>>>>>>>>> [email protected]> wrote: >>>>>>>>>> >>>>>>>>>>> How are you recording the samples? >>>>>>>>>>> >>>>>>>>>>> On Thu, Nov 19, 2015 at 1:05 PM, mourad ghafiri < >>>>>>>>>>> [email protected]> wrote: >>>>>>>>>>> >>>>>>>>>>>> Hello; >>>>>>>>>>>> >>>>>>>>>>>> please any help to figure out what is the Intermediate >>>>>>>>>>>> Frequency used for HackRF in Gnuradio... >>>>>>>>>>>> >>>>>>>>>>>> I'm recording a streaming file for GPS and I don't know what is >>>>>>>>>>>> the appropriate type ( int; float...) and what is the appropriate >>>>>>>>>>>> IF to use >>>>>>>>>>>> in order to process that streaming in Matlab. >>>>>>>>>>>> >>>>>>>>>>>> Best Regards; >>>>>>>>>>>> >>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>> HackRF-dev mailing list >>>>>>>>>>>> [email protected] >>>>>>>>>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>> >>>> >>> >> >
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