Yes, I use it for another project which is a pulse FMCW radar project In this project, we need an LFM with receiving time (dead-time) for testing the function of the radar (transmitter and receiver etc..)
Do you have any tutorial to modify the block of GNU Radio? I am a hardware guy so it may take some time to implement this work so I would appreciate it if you can help me how to modify it Thank you very much On Thu, Jul 8, 2021, 18:07 Alex Batts <[email protected]> wrote: > What on the other device are you trying to measure? Are you simply > attempting to see if you can receive a signal, or are you trying to receive > information of some kind? > > Generating an LFM signal is no problem, and modifying the source code is a > good way to go if that's all you want to do. You are right though about the > 56 MHz bandwidth, and the sample rate may affect your chirp > repetition frequency. > > Thanks, > > Alex > > On Thu, Jul 8, 2021 at 11:20 AM Pham Van Dung <[email protected]> wrote: > >> Thank Alex for your answer, >> >> For the second question, I will not design a pulse doppler radar with a >> linear FM pulse. But I wonder that I could generate an LFM signal (to >> measure another RF device at 1GHz) using Ettus B200? >> >> Due to the limit of the hardware capabilities, I think I can only >> generate an LFM with a maximum ~ 56 MHz sweep bandwidth (if possible). >> >> My approach is the modification of the source code of the FMCW block >> using OutOfTreeModules with gr_modtool, >> >> In which I will add the deadtime at the end of each FMCW pulse but I >> think I will not trade with my time to do this problem because I have >> already another solution :D >> >> Again, I appreciate your help and time in advance >> >> Vào Th 5, 8 thg 7, 2021 vào lúc 16:16 Alex Batts <[email protected]> >> đã viết: >> >>> Hello, >>> >>> It has been a while since I used the FMCW block in the Radar toolbox, >>> but from what I can remember, the three samples sections are defining the >>> percentage of the signal you want distributed in each of those sections. >>> For example, if you want 50% of your signal to be CW, and 50% to be >>> up-chirp, put an equal number of samples in the Samples CW and Samples >>> up-chirp sections. The number of samples combined with your sample rate and >>> frequency sweep will determine the slope of the fm chirp. >>> >>> There is also a VCO block I'm pretty sure that you can use for more >>> customizable fmcw radar. >>> >>> For your second question, why do you want to add a dead time? My guess >>> would be because you are trying to do pulse doppler of some sort, but if >>> not please explain because I would definitely be interested in knowing what >>> you are attempting to do! If you are trying to do a pulse doppler radar >>> with a linear fm pulse compression, unfortunately, there isn't much >>> functionality within GNU Radio for that kind of thing, and SDRs aren't >>> great for pulse doppler right now. In a few years' time they will, but most >>> affordable SDRs just don't have the hardware capabilities necessary. FMCW >>> is the way to go for SDRs because of low peak power needed and because >>> timing is not as necessary for range disambiguation, which is nice because >>> of the low sample rates of most SDRs. >>> >>> I am not sure you can implement a dead-time within the FMCW signal >>> generator block, and am not sure that gr-radar has that capability. >>> However, if you still want to implement a dead-time, you could write a >>> custom block (GNU Radio has extensive tutorials on how to do this, and only >>> requires basic knowledge of yaml and c++). I would do something like, >>> generate a sine wave, and while the sine wave is above a certain threshold, >>> send the fmcw signal through, else, send a constant 0 through. You would >>> have to play around with the threshold to get the proper duty cycle and >>> play around with the frequency of the sine wave to make sure you are >>> staying in sync with the signal generator, but that is one idea on how I >>> would do it off the top of my head. >>> >>> Can you give me more information on the project and/or what your goals >>> are? It would help me give more specific advice as opposed to shooting >>> blindly. >>> >>> Thank you, >>> >>> Alex >>> >>> On Thu, Jul 8, 2021 at 5:44 AM Pham Van Dung <[email protected]> >>> wrote: >>> >>>> Hello all, >>>> I want to make an FMCW signal generation with GNU Radar toolbox and >>>> Ettus B200 >>>> I saw that you have several examples in >>>> https://github.com/kit-cel/gr-radar/tree/master/examples/simulation, >>>> but I do not understand the following parameters of the FMCW block >>>> - Samples CW >>>> - Samples up-chirp >>>> - Samples down-chirp >>>> - Frequency CW >>>> Second question, if I want to modify the block (I want to add dead-time >>>> at each pulse of FMCW), How can I do it? >>>> I appreciate your help and time >>>> >>>> >> >> -- >> ----------------------------------------------------------------------- >> Van-Dung,PHAM >> >>
