Hi Vingnu, can you please try to keep discussions on the list?
I still don't understand: Your graph then tells me that the amplitude would be high over *bandwidths* of 60MHz, and low for *bandwidths *of 4MHz, right? Still, all your other explanations indicate you're talking about single tones (like the signal_generator_cw from the examples you cite generate), which don't have a bandwidth at all. This is all very contradicting! Best regards, Marcus On 16.12.2015 06:03, vingnu GNU wrote: > 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 <[email protected]> wrote: > >> ---------- Forwarded message ---------- >> From: Marcus Müller <[email protected]> >> Date: Tue, Dec 15, 2015 at 4:49 PM >> Subject: Re: [Discuss-gnuradio] (no subject) >> To: vingnu GNU <[email protected]>, Kevin McQuiggin <[email protected]>, >> GNURadio Discussion List <[email protected]> >> >> >> 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 <[email protected]> >> <[email protected]> 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 <[email protected]> >> <[email protected]> >> >> 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 < >> >> [email protected]> >> >> 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 < >> >> [email protected] >> >> 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 [email protected]:// >> >> lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> _______________________________________________ >> Discuss-gnuradio mailing >> [email protected]https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> _______________________________________________ >> Discuss-gnuradio mailing >> [email protected]https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> >> >>
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