Generate a specific wave form

GNU Radio
21

Hi,
sadly, I still don’t understand:
your control won’t be 0 or 1 forever. What do you do with the signal
that comes in while it’s 0? Will it be forgotten? Will it be saved for
the time when control is 1 again?

Hence, I’ll just repeat my question, could you please say “a”, “b”, “c”
or “none of these”?

Let’s define:
n_in = samples going into your “tap”
n_out = samples coming out of your “tap”
n_ctrl = control values going into your “tap”

While the control is 0, do you
a) want your samples coming out of the “tap” to be constant 0, meaning
that n_in=n_out=n_ctr, OR
b) want the samples to just be dropped, n_in = n_ctrl, n_in < n_out;
c) you want your tap to just let samples through when control is 1, so
that it behaves like a real water tap, holding water back, meaning that
n_in = n_out > n_ctrl

Best regards,
Marcus

22

Marcus,

I’ll send information only if no one else is sending. So, 0/1 will just
tell me when I can send my data (0 = I can’t; 1 = I can).

Zero means another person is using the spectrum, so my data will be
lost, because that’s not my band, I just want to use it for a short
period of time.
One means “free”, so I will pass/send my data.

I need to generate this 0/1 in a random way. That’s it. In my
application, I’ll always have 0 or 1.

Thank you.

23

On 02/07/15 15:05, Antonny C. wrote:

I’ll send information only if no one else is sending. So, 0/1 will just
tell me when I can send my data (0 = I can’t; 1 = I can).

Zero means another person is using the spectrum, so my data will be
lost, because that’s not my band, I’m just using it for a short period
of time.
One means “free”, so I will pass/send my data.

I need to generate this 0/1 in a random way. That’s it. In my
application, I’ll always have 0 or 1.

Antony, you are starting to repeat yourself in circles. Somehow you are
unable to clearly express what you want to do (not the general concept,
but the fine details of it), which solutions you tries and what problems
you encounter.

Also, it does not help that you ignore the questions of whom is trying
to help you. I’ll ask you again: do you mean that you want to “pause”
the transmission or that you want to “mute” the transmission?

It is still not clear where you are encountering problems. From the
above it seems that you do not know how to generate a 0/1 random stream.
Is it that your issue?

Cheers,
Daniele

24

Could you really please answer my question, a,b,c or none of these?

25

Daniele,

I just want a kind of “random multiplyer”. It’s necessary to lose the
signal when I can’t send it. I still don’t have details about my
purposes after that, but it’s not necessary. I just want pass or not my
sine wave to the output without changing it.

Thank you.

26

Marcus,

Letter c.

Thank you.

27

Cool! Now I know what kind of system we’re talking about.

The problem is now:
If you just lay after “chunk” of signal that passes through your tap one
after another, you’ll end up with exactly the signal you fed into the
tap, only sliced:

http://imgur.com/aa4ZjR2

Now, what GNU Radio does is just put the output of each block just after
it’s last output and let the downstream block work on it.
To that downstream block therefore just sees exactly the same signal
as your tap. Your tap hence does nothing. It only slows down the
processing speed, but that doesn’t have any influence on the signal
itself – GNU Radio blocks don’t know the “real world time”, and all
time that matters is actually just the number of the sample that you
see.

That’s why I’ll ask you to make a sketch (can be on paper, doesn’t
matter, really) of what your overall system should do, from RX antenna
to TX antenna. Just an implementation-agnostic quick sketch of where
which kind of signals come in, where a decision happens etc.
GNU Radio has multiple methods of dealing with such “chunky” data, but I
think you might be a bit mislead on what you think GNU Radio can do for
you.

Best regards,
Marcus

28

Nathan,

I see what you mean, but one thing I don’t understand is (don’t get me
wrong): Why do you wanna know everything I wanna do and the purpose of
my research?

For now, what I need is this “random multiplier”. That’s it!
I’m trying to do it for a long time and I didn’t understand the problem
I’m having, so I came here to ask you for help.
If you don’t want or can’t help me, that’s okay.

Thank you.

29

I’d hate to be ‘that guy’, but this thread is getting a little
ridiculous
at this point (actually it started out a bit silly with a request for a
flowgraph to generate some random FSK signal from a picture). Antonny,
it’s
pretty common when learning new software or tools that you can’t
immediately jump in to do exactly what you want. I suggest going through
the guided tutorials (
http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorials)
1,2,6,7 at the bare minimum.

Also, if you want strangers on the internet to generate an exact signal
you
need to be more explicit in your communication and requirements. There
are
several contradicting requirements I’ve seen here which is why you’ve
received 6 solutions from 5 people. Going through the tutorials to
understand GNU Radio better may help with this (or maybe not).

After the tutorials put in some effort to play around with GNU Radio
blocks
trying to generate the signal you want (after all only you know exactly
what you want). If you don’t succeed after an honest attempt come back
explaining what you’ve done and why it doesn’t fit what you need. Then
maybe we can point you towards the final steps.

Cheers,
Nathan

PS- like Marcus said in the first reply, please sign up for the mailing
list. Ruby-forum is really annoying.

30

Antonny,

Why do you wanna know everything I wanna do and the purpose of
my research?
Two things:
a) we’re just naturally curious, since we are developers and
researchers; but here more importantly:
b) it’s been very hard to understand what you want.

All the people that have answered you are experienced in software
development and well-used to GNU Radio. You have not really shown to be
highly capable of tapping that resource.

For now, what I need is this “random multiplier”. That’s it!
Yet another contradiction!

So this random multiplier would be extremely easy to build if that was
what you wanted. It’s likely not, because we have pointed you to the
multiplier block, and you were not satisfied. So we try to help you, and
to do that, we try to understand what you actually want to do.
You’ve started with showing us a diagram without axis labels and said “I
need this signal”. What?! We’re really trying to understand what you’re
doing, but you started off with “I need this signal”, switched over to
“I need something to stop the flow of samples at times”, and now we’re
back to “I need a multiplier”. All this doesn’t make any sense. I’m left
with the feeling you’re not half sure what you actually want to do. So
the natural approach here is asking you to give us an idea of what you
want to do, from a perspective “further away”.

If you don’t want or can’t help me, that’s okay.
I think 17 email replies (including this one) is a clear sign: We want
to help you :slight_smile: Now it’s my turn to ask you to not get this wrong:
You’re just making it really hard to do so. Most people would have,
especially after being asked to do so, long come up with a graphical
overall sketch of the parts of your system, but you’re ever so dodging
specific questions; no wonder we haven’t worked out something together.
I had to ask three times to answer me an a/b/c question, and you replied
with something that contradicts the “random multiplier” you’re
mentioning now; that’s not really a basis for cooperation.

I think Nathan really hit the spot: You’re not really good at explaining
what you actually want to do, which definitely also happens because
you’re not very familiar with how GNU Radio makes you work. That’s not
your fault – but it can really only be solved by going through some
kind of training, which is what the guided tutorials do.

Your problem is either extremely simple, in which case you should be
able to solve it yourself as soon as you’re familiar enough with GNU
Radio, or it’s quite complex, in which case you need to be quite used to
the tools you have to even communicate your approaches and problems.

Best regards,
Marcus

PS: No one here is taking offense in you wondering why we ask so many
questions, but as a hint for the future: Whatever you do, always be
thankful and open if people show interest in your research and
development, especially if these people might end up spending time
helping you, and I think it’s pretty obvious that if someone tries to
help you, and he asks for a bit of background on what you’re doing,
that’s because it might help him help you. How can you not assume this?

31

To clarify:

Antonny C. wrote in post #1176215:

I’m trying to do it for a long time and I didn’t understand the problem
I’m having, so I came here to ask you for help.

It’s not my fault, I tried a lot (using tutorials, etc) and then I came
here. But it’s okay. Thank you for your efforts so far (no need to
answer here anymore - finished subject).

Cheers,
Antonny

32

On Mon, Jul 6, 2015 at 10:13 AM, Antonny C. [email protected]
wrote:

Nathan,

I see what you mean, but one thing I don’t understand is (don’t get me
wrong): Why do you wanna know everything I wanna do and the purpose of
my research?

I don’t.

For now, what I need is this “random multiplier”. That’s it!
I’m trying to do it for a long time and I didn’t understand the problem,
so I came here to ask you for help.
If you don’t want or can’t help me, that’s okay.

What have you done so far? Have you taken time to learn GNU Radio in any
way? The tutorials I linked to were written by a group that really wants
to
help people in your situation. I can’t recommend them enough.

It’s not that I can’t help you, it’s more that the community can’t
help
you until you try to help yourself a bit first. You got four individuals
to
give at least five different solutions that all failed to give you what
you
wanted. I guarantee that GNU Radio is capable of doing what you want to
do,
but none of us can figure out what that is so far.

Thank you.

–
Posted via http://www.ruby-forum.com/.

I really hope I’m not being abrasive in some way, but there’s an easy way
and a hard way to learn new things. The hard way is to blindly dive in
the
deep end ignoring tutorials and guides while trying random things. The
easy
way is to use the resources such as tutorials, documentation, and
examples
to learn how to solve problems, then take that and apply it to your
problem. It sounds like you’re doing things the hard way.

Cheers,
Nathan