Re: [Discuss-gnuradio] (no subject)

[Marcus Müller]

Hi Vingnu,
> you are right I hope now you came to know my problem,I have got same
> question when i have seen those examples so I had asked question,
> whether am I able to generate such kind of continuous wave  from gnuradio(I
> am having hardware USRP E310) or not?
To be honest, you don't really seem to understand what kind of signal
you want.
A CW tone doesn't have any bandwidth. We can't thus tell you whether
what you want is possible.

Best regards,
Marcus


On 17.12.2015 05:46, vingnu GNU wrote:
> Hi,
> you are right I hope now you came to know my problem,I have got same
> question when i have seen those examples so I had asked question,
> whether am I able to generate such kind of continuous wave  from gnuradio(I
> am having hardware USRP E310) or not? because examples what I have gone
> through does not having bandwidth but what I am going to generate have some
> constant bandwidth of 60MHz and 4KHz(250usec) of dwell time.
> At least if it is not supporting 60MHz bandwidth is it will support for
> 25MHz?
>
> regards
> Vinay
>
> On Wed, Dec 16, 2015 at 10:50 AM, Marcus Müller <address@hidden>
> wrote:
>
>> 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 <address@hidden> 
>> <address@hidden> wrote:
>>
>>
>>
>> ---------- Forwarded message ----------
>> From: Marcus Müller <address@hidden> <address@hidden>
>> Date: Tue, Dec 15, 2015 at 4:49 PM
>> Subject: Re: [Discuss-gnuradio] (no subject)
>> To: vingnu GNU <address@hidden> <address@hidden>, Kevin McQuiggin 
>> <address@hidden> <address@hidden>,
>> GNURadio Discussion List <address@hidden> <address@hidden>
>>
>>
>>
>> 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 <address@hidden> 
>> <address@hidden> <address@hidden> <address@hidden> 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 <address@hidden> <address@hidden> 
>> <address@hidden> <address@hidden>
>>
>>
>> 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 <
>> address@hidden>
>>
>> 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 <
>> address@hidden
>>
>> 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
>>
>>
>>
>>
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