Re: [Discuss-gnuradio] Signal Processing Block with Control Port

[Benny Alexandar]

Hi,

I'm not sure about control port, you are asking for sending asynchronous input 
to blocks.  GNU Radio blocks shud support data as well as control ports, which 
will be of much use.

-ben

--
Hi,

Is it possible to make a signal processing block which contains two input 
ports, one is byte type and the other is complex type. The only output port is 
also complex type. The byte type input port would just act like a controller 
port that when it receives "1", it allows data to flow form input complex port 
to output complex port.
If it is not possible, is there any alternative way to do this job in gnuradio 
companion?




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[Discuss-gnuradio] Signal Processing Block with Control Port

[Hafiz Hashim Imtiaz]

Hi,

Is it possible to make a signal processing block which contains two input
ports, one is byte type and the other is complex type. The only output port
is also complex type. The byte type input port would just act like a
controller port that when it receives "1", it allows data to flow form
input complex port to output complex port.
If it is not possible, is there any alternative way to do this job in
gnuradio companion?




regards,
Hafiz Hashim Imtiaz
Research Assistant
Information Technology University, Punjab
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Re: [Discuss-gnuradio] Frequency sweep using GNU

[Marcus Müller]

Hi Abhilash,

> I want to experiment in the wifi band (i.e 2.4-2.8GHz).
That kind of annoys me: that's not the "WiFi band". It's the 2.4 GHz ISM
band, which different WiFi standards tend to use. However, there's a
bazillion other things using that band, so you'd do me (and all these
other applications) a favor if you're not naming it as if it was
spectrum that is assigned to WiFi usage. It's not; there's RC toy
controls, camera links, bluetooth, door openers, mesh networks, medical
devices, wireless mice and keyboards, …

> I am not sure about how long to linger on one frequency.
Well, obviously, this is a system design challenge that we can't answer
for you: dwell time increases resolution and certainty, but inherently
means your sweeping takes longer. So, **you** will need to define a
reasonable timing first, and after you've done that, let's discuss how
you could implement that. The other way around doesn't make any sense.
Since your signature says "research scholar", I'm pretty optimistic you
can describe your signals of interest well enough in a simple signal
model that you can derive a formula for how long your observation per
step needs minimally be.

> I am trying to understand basic wireless channel effects like path
> loss, fading for different frequencies in the specified band.
Well, that's pretty close to a description of the channel model that is
of interest here. You might just want to define bandwidth that you'd
want to describe your channel under. Obviously, more bandwidth means
more info about the channel, but also more data, and also more chance
for multi-path to take effect, and make the channel frequency-selective
("coherence bandwidth"), and in that aspect maybe even time-variant
("doppler spread"). So, start by defining the bandwidth of the channel
you need to describe.

Then, there's textbooks worth of common knowledge about how long a
channel is expected to stay as it is ("coherence time").

Best regards,

Marcus


On 02.10.2017 07:44, abhilash b wrote:
> Thank you for your reply in GNU radio forum for the message ID
>   >
>
> Here are the details: 
>
> I will be using USRP N210 with CBX daughter board. I want to
> experiment in the wifi band (i.e 2.4-2.8GHz).
> I am trying to understand basic wireless channel effects like path
> loss, fading for different frequencies in the specified band.
>
> Currently, I am not sure about how long to linger on one frequency. I
> will be placing the transmitter on a drone and hover it. Hence I will
> have control just before the flight and I want the sweeping to repeat
> at regular intervals. I will be placing BladeRF on the drone and USRP
> will be on the ground.
>
> If it's not possible to sweep with such little steps, I have the
> freedom to vary the step size.
>
> Please provide me the approaches (or any links) to solve this
> frequency sweeping issue. 
>
> -Regards
> Abhilash B
> Research Scholar
>
>
>
>
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Re: [Discuss-gnuradio] Sample rate block in GNU radio

[Kyeong Su Shin]

Hello Abhilash B:

The 10 samples will keep get repeated, until you manually stop the program
(they will be transmitted over again and again without a pause, until you
stop the program). The 20MHz sampling rate will determine the output speed
(DAC samp rate) of your SDR - assuming that the sampling rate of your SDR
sink block is set to 'samp_rate'. If you did not use the samp_rate variable
block anywhere in your flow graph, it simply does nothing.

Please note that USRP uses I-Q sampling; you should feed in complex
numbers, instead of the real float. Also, I do not know how your 'dat' file
is structured - it should contain raw IEEE754 single precision numbers
(something to double check if your program misbehaves).

Regards,
Kyeong Su Shin

On Sun, Oct 1, 2017 at 10:41 PM, abhilash b  wrote:

> Hello all,
>
> Following with my previous email regarding the sample_rate block,
>
> > Hello all,
> > I am new to GNU radio and I have one basic query.
> >
> > Suppose I am having 10 samples and I set sample rate at 20MHz with
> > repeat option ON (assuming my hardware supports this bandwidth).
> > Is that means my samples first gets repeated 20M samples and gets
> > transmitted at once?
> >
>
> Here repeat option related to  File_source block. Basically, I generate
> float symbols in Matlab and convert it to /.dat/ file. I use this .dat file
> in the file_source block, turn on /Repeat/ option, and transmit through
> Osmocom/USRP sink
>
>
> --
>
>
> -Regards
> Abhilash B
>
>
>
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