Re: [Discuss-gnuradio] (no subject)

[Neil Schafer]

I don't want to speak for Vingnu but I believe there might be some confusion in 
terminology here.

I think Vingnu is trying to accomplish the following:
Sweep from 1GHz to 2GHz with constant tones increasing in steps of 60Mhz, with 
each tone held for 250usecs, and that is all. 
So 1GHz held for 250usec, then 1.06GHz for 250usec, then 1.12GHz for 250usec, 
and so on.

The constant tone is therefore changing at a rate of 4kHz. I think the 
frequency change of the constant tone is being confused for bandwidth. 
This doesn't exactly match the diagrams but makes the most sense to me.

Does this sound like what you are trying to accomplish, Vingnu?

Regards,
Neil



-----Original Message-----

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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