Hi, This is regarding x and y axis of graph what I have posted in last post. (1)Y-axis is amplitude and (2)X-axis is frequency.Amplitude remains constant and frequency has to be increase in terms of steps(60MHz). Examples what I have referred for CW is USRP echotimer _CW in (exaples USRP) and simulator_CW (in simulators) these examples are from gr-radar tool kit.
regards Vinay On Wed, Dec 16, 2015 at 10:04 AM, vingnu GNU <vingnu...@gmail.com> wrote: > > ---------- Forwarded message ---------- > From: Marcus Müller <marcus.muel...@ettus.com> > Date: Tue, Dec 15, 2015 at 4:49 PM > Subject: Re: [Discuss-gnuradio] (no subject) > To: vingnu GNU <vingnu...@gmail.com>, Kevin McQuiggin <mcqui...@me.com>, > GNURadio Discussion List <discuss-gnuradio@gnu.org> > > > Hi Vinay, > > Really sorry for images sizes > > Don't be sorry! A few hundred kilobyte won't break the mailing list, and > it's always a good thing to illustrate your system well; I've spent much > (too much?) time in university labs, and believe me, there's nothing more > crucial about science and technological progress than to be able to > communicate your knowledge; pictures are a very good way of doing that. > > So: let's consider this: > [image: Waveform] > Since we're talking about SDR with USRPs, there's two ways you can > interpret this graphic, if it stands alone: > > 1. This is the equivalent baseband signal, or > 2. This is the electrical signal as "seen" by the antenna (RF signal). > > Considering the time axis, the first (0-2ns) slot has 1GHz of frequency, > and the second period (4ns-6ns) has 2GHz. That means that (since there is > no USRP with a >=2GHz sampling rate) this can only be interpreted as the > antenna signal, so this is case 2. > This means that, yes, this is possible in principle, but not quite in the > shape shown: you tune your USRP to frequency 1, and transmit a constant > baseband value (e.g. 1+0j) for your "dwell time"; then, you start tuning to > the next frequency, and transmit 0's, and then another "dwell time" worth > of constant value, and so on. > > Aside from the obvious timing impossibility (the shown waveform has a tone > duration of 2ns; that won't be possible with any USRP; our DAC/ADC don't > exist in a 500MS/s variant so far), you cannot continue the wave at the > same zero phase, so the phase of the wave at each transmission start won't > be zero, but some other value. However, there are USRP/daughterboard > combinations that allow for a fixed phase reconstruction at tuning. Hence > my *repeated* question: What is your USRP, and if applicable, your > daughterboard?¹ > > Then, you have a second picture, which I admittedly really do not > understand: > [image: What's this?] > I had the feeling that this was some kind of Y-over-X graph, but I really > could not tell what the axis and the meaning of your line are, so could you > please define ?1 and ?2, as well as explain what the graph means? What > happens there? > > > Best regards, > Marcus > > ¹I really usually don't nitpick, but it's really hard to get the > information out of you to help you, so I'm asking you explicitly: Please > always answer all questions we ask so that we can actually help you! > > > On 15.12.2015 07:30, vingnu GNU wrote: > > Hi, > This is the wave form I required to generate and Its a step frequency CW > starts from 1GHz and ends with 2GHz,constant incremental steps of 60MHz and > 4KHz of dwell time. pic2 shows the waveform in frequency Vs time domain. > Really sorry for images sizes > [image: Inline image 1] > > [image: Inline image 2] > Regards > Vinay > > > On Mon, Dec 14, 2015 at 6:01 PM, Kevin McQuiggin <mcqui...@me.com> > <mcqui...@me.com> wrote: > > > Hi Vingnu: > > Perhaps you mean a swept frequency from 1 GHz to 2 GHz? The group needs > further information. > > Kevin > > Sent from my iPad > > > On Dec 14, 2015, at 4:25 AM, Marcus Müller <marcus.muel...@ettus.com> > <marcus.muel...@ettus.com> > > wrote: > > Hi Vingnu, > > so you mean that on one frequency, you want to have a CW tone, and one > the next frequency another etc, but not continuous phase across > > frequencies. > > ** Do I understand that correctly? ** I'm confused because you then > mention "pulses", and that is a concept that is incompatible with CW > > radar. > > Hardware-wise, most USRPs (which one are you using) support timed > commands so that you can tune at a specific sample time. For those that > don't, you'll have to use some time buffers, but it's essentially what > the example probably does that you cite -- though you're not really > telling me which example exactly you're referring to. > > All in all, please try to make your questions a little more precise, add > all the details that are important right from the start. > > Best regards, > Marcus > > > > On 14.12.2015 12:05, vingnu GNU wrote: > Hi , > That is nothing but in examples of USRP they have used FMCW for target > simulator with frequency modulated CW here in my case I am going to use > unmodulated CW . > My question was ,is it possible to increment this CW signal source > > interms > > of 60MHz step size and keeping 250usec of dwell time between 60MHz steps > and it should be upto 2GHz and repeating same in next cycle. > ex: first frequency is 1GHz it has to add 60MHz step size and keep > > 250usec > > of dwell time i.e.,after 1.06GHz pulse it has to maintain 250usec dwell > time before next 60MHz pulse . > > regards > vingnu > > On Mon, Dec 14, 2015 at 3:44 PM, Marcus Müller < > > marcus.muel...@ettus.com> > > wrote: > > > Hi Vingnu, > that's all nice, but what does "continuous wave" _mean_? > > Best regards, > Marcus > > > On 14.12.2015 10:02, vingnu GNU wrote: > Hi marcus, > > Its like this : generating continuous wave of signal which starts from > > 1GHz > > and it has to increase in steps of 250usec upto 2GHz.Then I wanted to > > feed > > it for Radar transmitter.Its like generating Step frequency continuous > > wave > > signal for radar transmitter. Is it possible from GNU radio and I am > > having > > USRP E310 right now. > > regards > Vingnu > > On Mon, Dec 14, 2015 at 2:06 PM, Marcus Müller < > > marcus.muel...@ettus.com > > wrote: > > > Hi Vingnu, > > note that GNU Radio is software that handles sample streams, so yes, > > any > > signal that you can imagine in a given bandwidth can be generated; > > the > > question is whether you can realize that signal in the physical > > world. > > So: > > * do you just want to simulate the signal or really transmit that? > * if you want to transmit that, with which hardware? > * what exactly is "continuous wave" for you here? Continuous for a > > single > > frequency step, or continuous across multiple frequencies? > > Best regards, > Marcus > > > On 14.12.2015 05:59, vingnu GNU wrote: > > Hi every one, > > Is this possible to generate step frequency continuous wave for > > frequency > > range of 2GHz to 4GHz in GNU radio and step size in range of 250micro > seconds(Dwell time). > > regards > Vingnu > > > > > _______________________________________________ > Discuss-gnuradio mailing listDiscuss-gnuradio@gnu.orghttps:// > > lists.gnu.org/mailman/listinfo/discuss-gnuradio > > _______________________________________________ > Discuss-gnuradio mailing > listDiscuss-gnuradio@gnu.orghttps://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > _______________________________________________ > Discuss-gnuradio mailing > listDiscuss-gnuradio@gnu.orghttps://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > >
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