Re: [Discuss-gnuradio] [ Calculating the amplitude of a signal source ]

[Ashish Raste]

Hi Nazmul,

I have always found it difficult to measure the amplitude of each sample
> using the floating point strengths. Things like frequency offset will
> change the result and affect the individual samples.
>

I thought I need to do some calibration to correlate the value shown in the
y-axis of the Scope sink (some factor X amplitude of the source signal) to
the signal strength sent from the generator.


> However, calculation of average power based floating point strength works
> for me. For example, I have measured the power of a received sinusoid using
> FFT. The strength of the floating point outputs of FFT
> scale expectantly with the transmitted power.
>

Thanks for this suggestion. I will do this experiment.

Best,
-- 
Ashish Raste
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Re: [Discuss-gnuradio] [ Calculating the amplitude of a signal source ]

[Ashish Raste]

Hi Marcus,


What daughter card are you using?   What is your tuned frequency?  What is
> the frequency of the signal source?  What is the amplitude of
>   the signal source?
>

I'm using the USRP N210 with WBX daughterboard. Am having a vector signal
generator which is sending the signal at 400.01M frequency and the USRP
source block's frequency is set to 400M.


-- 
Ashish Raste
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[Discuss-gnuradio] real time voice transmission

[lingeswar kandregula]

hi community,
 i just wanted to have a real time voice transmission between two usrp
boards. i tried tx_voice.py and rx_voice.py files. at the receiver i didn't
get anything. can anybody suggest me what to do to get the voice at
receiver.

thanks

lingeswar
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Re: [Discuss-gnuradio] hi to all,

[sivakumar reddy]

Thank you friend,
where can i get tutorials regarding "how to use each block in GNU radio
companion"?
Thanks in Advance
any replies are appreciated


On Mon, Dec 10, 2012 at 8:08 AM, Tom Rondeau  wrote:

> On Fri, Dec 7, 2012 at 4:52 AM, sivakumar reddy 
> wrote:
>
>> Can any body explain how to use CYCLIC PREFIX  OFDM block in gnu radio,
>> how can we make SERIAL TO PARALLEL conversion in GNU radio.
>> Advance thanks
>> any replies are appreciated
>>
>
> The cyclic prefix block takes in a vector of samples that represents a
> single OFDM symbol and then copies the last (output_size-input_size)
> samples from the back of the symbol to the front.
>
> To convert S2P, use the gr_stream_to_vector block.
>
> Tom
>
>
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Re: [Discuss-gnuradio] Reference for cmake

[Josh Blum]

On 12/10/2012 10:48 PM, Karan Talasila wrote:
> Hi All,
>  I just wanted to know if gnuradio has any appropriate guide on
> using cmake instead of normally used cmake. All the tutorials and guides
> written use old makefile.am utility. It would help me in my execution if
> there are any gnuradio specific cmake reference.


This should help a lot:
http://gnuradio.org/redmine/projects/gnuradio/wiki/CMakeWork

Cheers,
-josh

> 
> 
> 
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[Discuss-gnuradio] Reference for cmake

[Karan Talasila]

Hi All,
 I just wanted to know if gnuradio has any appropriate guide on
using cmake instead of normally used cmake. All the tutorials and guides
written use old makefile.am utility. It would help me in my execution if
there are any gnuradio specific cmake reference.

-- 
Regards
Karan Talasila
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Re: [Discuss-gnuradio] [ Calculating the amplitude of a signal source ]

[Nazmul Islam]

Hi Ashish,

I have always found it difficult to measure the amplitude of each sample
using the floating point strengths. Things like frequency offset will
change the result and affect the individual samples.

However, calculation of average power based floating point strength works
for me. For example, I have measured the power of a received sinusoid using
FFT. The strength of the floating point outputs of FFT
scale expectantly with the transmitted power.

Thanks,

Nazmul

On Mon, Dec 10, 2012 at 11:09 PM, Ashish Raste wrote:

> Hi Nazmul,
> Thanks for replying.
>
>
> Change the Receiver gain and see if the strength/amplitude of the floating
>> points change or not. If they do, then you are doing the right thing. You
>> can place a signal calibrator (e.g. some variable attenuator) to calibrate
>> the floating point strengths and actual received power.
>
>
> I did notice significant change in the floating point values recorded when
> the gain was changed. Have attached the plots of those values for the gain
> values of 20 dB and 25 dB.
>
> I also see that these values do not depict the sine wave (the source being
> a sine wave). So can I assume that these floats are not exactly the
> amplitudes but they have some relation to the amplitude of the signal? How
> can I calculate the amplitude from this recorded data (file_sink)?
>
> Thanks and Regards,
>
> --
> Ashish
>
>
>
>


-- 
Muhammad Nazmul Islam

Graduate Student
Electrical & Computer Engineering
Wireless Information & Networking Laboratory
Rutgers, USA.
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Re: [Discuss-gnuradio] [ Calculating the amplitude of a signal source ]

[Ashish Raste]

Hi Nazmul,
Thanks for replying.


Change the Receiver gain and see if the strength/amplitude of the floating
> points change or not. If they do, then you are doing the right thing. You
> can place a signal calibrator (e.g. some variable attenuator) to calibrate
> the floating point strengths and actual received power.


I did notice significant change in the floating point values recorded when
the gain was changed. Have attached the plots of those values for the gain
values of 20 dB and 25 dB.

I also see that these values do not depict the sine wave (the source being
a sine wave). So can I assume that these floats are not exactly the
amplitudes but they have some relation to the amplitude of the signal? How
can I calculate the amplitude from this recorded data (file_sink)?

Thanks and Regards,

-- 
Ashish
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Re: [Discuss-gnuradio] News on Bugs & Issues

[Tom Rondeau]

On Mon, Dec 10, 2012 at 5:21 PM, Martin Braun (CEL) wrote:

> Hi everyone,
>
> starting now, we would like to re-introduce the GNU Radio issue tracker.
> If you don't know what I'm talking about, it's what you get when you
> click 'Issues' on our website:
> http://gnuradio.org/redmine/projects/gnuradio/issues




First of all, thanks to Martin for coordinating this, and I'll second our
thanks to Ben for stepping up to help us manage the system!


> So how does this work now?
> Say you've discovered a bug, and know how to patch it. You write the
> patch, and submit the patch file to the issue tracker, along with a
> description of the problem (or you link to your github with the fixed
> code).
> When that happens, one of us checks the issue. It might get rejected
> (perhaps it violates coding conventions, or the bug fix itself is buggy),
> but most likely, it gets assigned to one of the developers. What happens
> then depends on the issue at hand, but the goal is to close issues ASAP.
> Bug fixes will usually go into the next minor release, anything API
> changing into the next major release.
>

One thing that I wanted to add here. Sometimes we'll come up with a bug
that we don't know how to write a patch for. If that's the case, the thing
that will help us more than anything is a small, simple test program that
demonstrates the bug. The easier it is to reproduce the problem with as
minimal amount of code required, the easier it'll be to track down, write a
patch, and test it.

Otherwise, just do as Martin says and we can all start to benefit!

Tom
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[Discuss-gnuradio] News on Bugs & Issues

[Martin Braun (CEL)]

Hi everyone,

starting now, we would like to re-introduce the GNU Radio issue tracker.
If you don't know what I'm talking about, it's what you get when you
click 'Issues' on our website:
http://gnuradio.org/redmine/projects/gnuradio/issues

The issue tracker has been unmaintained for quite a while, but we've
cleaned it out and will go back to using that.

For you guys, this means:
- The tracker is the one place to go for bug reports, patches, feature
  requests and any other issue. The patch-gnuradio mailing list will be
  made obsolete soon.
- If you have a bug report, patch etc. please post it directly to the
  tracker. This way, we can keep track of open bugs much better; also,
  any discussion specific to this patch is kept out of the way of this
  mailing list.
- We welcome everyone to sign up on gnuradio.org to use the issue
  tracker. Unfortunately, we still have to manually activate your account
  to post on the wiki and bug tracker because of spam accounts, but a
  quick email to me off-list will take care of that easily. If you don't
  wish to sign up, you can still use the guest:gnuradio account.
- The big advantage is that we will try to handle issues much quicker
  than before (no more than 1-2 weeks until something happens with your
  issue).

To get all of this working, Ben Reynwar has volunteered to be the chief
bug tracking officer of GNU Radio (thanks a lot, Ben!). He will make
sure bugs are assigned to developers, and that developers don't ignore
bugs assigned to them. This way, we hope to keep the half-life of open
issues short, and tie in developers other then the few heads of GNU
Radio more closely.


So how does this work now?
Say you've discovered a bug, and know how to patch it. You write the
patch, and submit the patch file to the issue tracker, along with a
description of the problem (or you link to your github with the fixed
code).
When that happens, one of us checks the issue. It might get rejected
(perhaps it violates coding conventions, or the bug fix itself is buggy),
but most likely, it gets assigned to one of the developers. What happens
then depends on the issue at hand, but the goal is to close issues ASAP.
Bug fixes will usually go into the next minor release, anything API
changing into the next major release.


By implementing these changes, we're hoping to make the issue process
more tangible and get code submissions into our tree faster.
It might take a couple of weeks before everyone runs smoothly, but
eventually it should make collaboration on this awesome project much
smoother.

If you have any questions, please ask on-list so we can make this as
transparent as possible.

Cheers,
MB

-- 
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

Dipl.-Ing. Martin Braun
Research Associate

Kaiserstraße 12
Building 05.01
76131 Karlsruhe

Phone: +49 721 608-43790
Fax: +49 721 608-46071
www.cel.kit.edu

KIT -- University of the State of Baden-Württemberg and
National Laboratory of the Helmholtz Association


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Re: [Discuss-gnuradio] Quadrature rate question

[Tom Rondeau]

On Mon, Dec 10, 2012 at 7:40 AM, Martin Braun (CEL) wrote:

> On Mon, Dec 10, 2012 at 01:05:13PM +0100, Martin Braun (CEL) wrote:
> > On Mon, Dec 10, 2012 at 09:44:29PM +1000, Phil wrote:
> > > A recent post by Markus Gonser had me intrigued and so I
> > > experimented with his grc code. The resulting FM receiver does work
> > > but it doesn't quite sound right. My guess is that the quadrature
> > > rate is not correct at 705.6kHz. Is this the correct rate and if
> > > it's not what should it be?
> >
> > That depends. The quadrature rate is the rate of the incoming I/Q sample
> > stream. 705.6 kSps seems unusual, though.
>
> Actually, it's 16*44.1kSps, which isn't that unusual. Still, you need to
> get that rate at the input.
>
> MB
>

Yeah, if you're using a UHD device, you'll ask it for a specific rate. If
it can get that rate, everything's fine. If you are asking it for a rate
that it cannot achieve, it will give you a warning that you asked for rate
X but it was actually set to rate Y. If that's the case, you'll have a
sample rate mismatch between the two devices. You'll need to do some
resampling to get them to match.

Tom
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Re: [Discuss-gnuradio] Gerrit and Jenkins?

[Tom Rondeau]

On Mon, Dec 10, 2012 at 11:20 AM, Michael Dickens  wrote:

> Hi Tom - That's what I remembered, too, about Jenkins; and, what I had
> expected about Gerrit.  Give me another couple of months, and I'll be able
> to discuss the use of them intelligently.  Right now, I understand just the
> basics.  And, I'm not sure they make sense for GNU Radio given the size of
> the project (number of developers working potentially simultaneously on the
> same code; the number of top-level developers who make the decisions on
> what gets committed and what is rejected).  I'll try to remember to revisit
> this topic in a few months. - MLD
>
>
Understood, and thanks!

While not officially set up or announced, we are looking into reviving our
monthly project conference calls again soon (as in maybe next month). This
might be a good topic to discuss in that format.

Tom




> On Dec 10, 2012, at 11:13 AM, Tom Rondeau  wrote:
> > I'll probably need more time to review gerrit as a service to see what
> we can and want to use it for. We've had Jenkins running weekly builds and
> providing feedback for a long time now (gnuradio.org/jenkins), but we
> haven't really figured out how to make much use of it. I'm very interested
> in trying, though.
>
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Re: [Discuss-gnuradio] Questions about bbn_80211b_rx.py

[Kexiong Zeng]

I am not sure if you can see the picture attached, so I print out the
result.


shine@ubuntu:~/Projects/bbn_80211/branches/usrp2_version/gr-bbn/src/examples$
sudo ./bbn_80211b_rx.py -d 4 -f 2.412G -b -v
adc frequency =  1
decimation frequency =  4
input_rate =  2500
gain =  0.0
desired freq =  241200.0
baseband frequency 0.0
dxc frequency -1200.0
>>> gr_fir_ccf: using SSE
Recieved header!
  signal: 0x0A
  service: 0x04
  length: 0x0338
  crc: 0x09E8
Calculated crc: 0x09E8
Packet Length: 103 bytes.
128 0 0 0 255 255 255 255 255 255 192 193 192 78 119 29 192 193 192 78 119
29 64 142 131 137 23 63 13 0 0 0 10 0 1 0 0 9 100 117 114 104 97 109 51 54
53 1 4 130 132 139 150 3 1 1 5 4 0 1 0 0 221 9 0 16 24 2 0 240 4 0 0 221 24
0 80 242 2 1 1 128 0 3 164 0 0 39 164 0 0 66 67 188 0 98 50 102 0 171 186
167 118
PKT: len=99, rssi=-96, src=c0:c1:c0:4e:77:1D, time=5392, rate=1 Mbps
Payload:  ��Nw���Nw@�?

durham365



���P�

��'�BC�b2f
Recieved header!
  signal: 0x0A
  service: 0x04
  length: 0x0338
  crc: 0x09E8
Calculated crc: 0x09E8
Packet Length: 103 bytes.
128 0 0 0 255 255 255 255 255 255 192 193 192 78 119 29 192 193 192 78 119
29 96 142 131 217 23 63 13 0 0 0 10 0 1 0 0 9 100 117 114 104 97 109 51 54
53 1 4 130 132 139 150 3 1 1 5 4 0 1 0 0 221 9 0 16 24 2 0 240 4 0 0 221 24
0 80 242 2 1 1 128 0 3 164 0 0 39 164 0 0 66 67 188 0 98 50 102 0 167 157
54 131
PKT: len=99, rssi=-96, src=c0:c1:c0:4e:77:1D, time=25864, rate=1 Mbps
Payload:  ��Nw���Nw`�?

durham365



���P�

��'�BC�b2f
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Re: [Discuss-gnuradio] Gerrit and Jenkins?

[Michael Dickens]

Hi Tom - That's what I remembered, too, about Jenkins; and, what I had expected 
about Gerrit.  Give me another couple of months, and I'll be able to discuss 
the use of them intelligently.  Right now, I understand just the basics.  And, 
I'm not sure they make sense for GNU Radio given the size of the project 
(number of developers working potentially simultaneously on the same code; the 
number of top-level developers who make the decisions on what gets committed 
and what is rejected).  I'll try to remember to revisit this topic in a few 
months. - MLD

On Dec 10, 2012, at 11:13 AM, Tom Rondeau  wrote:
> I'll probably need more time to review gerrit as a service to see what we can 
> and want to use it for. We've had Jenkins running weekly builds and providing 
> feedback for a long time now (gnuradio.org/jenkins), but we haven't really 
> figured out how to make much use of it. I'm very interested in trying, though.

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Re: [Discuss-gnuradio] Gerrit and Jenkins?

[Tom Rondeau]

On Fri, Dec 7, 2012 at 10:39 AM, Michael Dickens  wrote:

> I'm wondering whether the GR "powers that be" are thinking that GR has
> gotten big enough to move to using "Gerrit Git Review with Jenkins CI
> Server"?  I'm now part of a project that's using it, and I also maintain
> (in MacPorts) the Qt port and the Qt project uses this method too; so I'm
> learning the ropes.  My initial impression is that it's a pretty useful
> method for distributed revision control when there are multiple developers.
>  I think the main points in this system are: code review prior to merging
> with the master including multiple patchsets for a given changeset, and
> integrated build testing for each commit.
>
> Here are some URLs:
>
> < http://alblue.bandlem.com/2011/02/someday.html >
> < http://alblue.bandlem.com/2011/02/gerrit-git-review-with-jenkins-ci.html>
> < http://vimeo.com/20084957 >
> < http://code.google.com/p/gerrit/ >
> < http://jenkins-ci.org >
>
> - MLD
>

Hi Michael,

I'll probably need more time to review gerrit as a service to see what we
can and want to use it for. We've had Jenkins running weekly builds and
providing feedback for a long time now (gnuradio.org/jenkins), but we
haven't really figured out how to make much use of it. I'm very interested
in trying, though.

Tom
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Re: [Discuss-gnuradio] hi to all,

[Tom Rondeau]

On Fri, Dec 7, 2012 at 4:52 AM, sivakumar reddy wrote:

> Can any body explain how to use CYCLIC PREFIX  OFDM block in gnu radio,
> how can we make SERIAL TO PARALLEL conversion in GNU radio.
> Advance thanks
> any replies are appreciated
>

The cyclic prefix block takes in a vector of samples that represents a
single OFDM symbol and then copies the last (output_size-input_size)
samples from the back of the symbol to the front.

To convert S2P, use the gr_stream_to_vector block.

Tom
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Re: [Discuss-gnuradio] transmiting a sequence of known bits using OFDM and file source

[Tom Rondeau]

On Thu, Dec 6, 2012 at 9:34 PM, jiajue ou  wrote:

> Hi all,
>
> I’m using a grc flow chart shown as below (also attached) to transmit
> data. My purpose is to transmit a sequence of known data bits specified by
> myself.  (These data bits are from Matlab.) So which file format should I
> use to feed into the File Source and how to set File Source output data
> type? Thank you very much in advance.
>
> ** **
>
> Best,
>
> Jia
>


Jia,

Use this as a guide:
http://gnuradio.org/redmine/projects/gnuradio/wiki/FAQ#What-is-the-file-format-of-a-gr_file_sink

The file sources take the same structure of data and insert them into a
flowgraph.

Tom
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Re: [Discuss-gnuradio] [ Calculating the amplitude of a signal source ]

[Nazmul Islam]

Change the Receiver gain and see if the strength/amplitude of the floating
points change or not. If they do, then you are doing the right thing. You
can place a signal calibrator (e.g. some variable attenuator) to calibrate
the floating point strengths and actual received power.

Thanks,

Nazmul

On Mon, Dec 10, 2012 at 4:03 AM, Ashish Raste  wrote:

> Hi all,
>
> For calculating the amplitude (assume RMS amplitude) of a signal source, I
> first tried to record the received samples (I'm using a vector signal
> generator) in a file_sink and then  thought to use it for my calculation.
> The frequency of the signal from the signal generator was set to 400M and
> the sampling rate of the USRP source block (in GRC) was set to 2M. Have
> attached the block diagram below:[image: Inline image 1]
>
> I am able to extract the float (the data type I used) values from the file
> but they are too small to be considered as amplitudes at different points
> in time i.e the maximum value was 1.03e-09 and minimum was -8.4e-13.
>
> Can anyone please tell me how I can calculate the amplitude of any such
> signal in real-time? Is this approach of calculating amplitude the right
> one OR is there any other smarter way to do it?
>
> Thanks and Regards,
> --
> Ashish
>
>
>
>
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>


-- 
Muhammad Nazmul Islam

Graduate Student
Electrical & Computer Engineering
Wireless Information & Networking Laboratory
Rutgers, USA.
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[Discuss-gnuradio] Value of noutput_items.

[Ahmed Zaheer]

Does anybody know the value of noutput_items in the work function. Is it 
possible to access a specific number of bits/bytes of a frame in GNURadio? How 
can I know the frame size which is passed from one block to another?

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Re: [Discuss-gnuradio] BBN_80211 Receiver on Gunradio 3.6

[Ulrika Uppman]

Hi, I haven't run the bbn-code with gnuradio 3.6 but I did with 3.3. The 
omnitreads aren't used anymore so try to include pthread instead. I believe it 
will be possible to get it running.


From: discuss-gnuradio-bounces+ulrika.uppman=foi...@gnu.org 
[mailto:discuss-gnuradio-bounces+ulrika.uppman=foi...@gnu.org] On Behalf Of 
Mohammed Karmoose
Sent: den 6 december 2012 19:14
To: discuss-gnuradio@gnu.org
Subject: [Discuss-gnuradio] BBN_80211 Receiver on Gunradio 3.6

Hi all,

I'm fairly new to Gnuradio. I've been trying to install BBN receiver on 
Gnuradio 3.6 and I've been getting errors of missing files like "omnithread.h" 
and others. I'm not going to get into the details of the issue here. I just 
want to ask those who were able to use it: Is it possible to install it on 
newer version of Gnuradio?

--
Thank you
---
Mohammed Hassan Karmoose
Teaching Assistant, Electrical Engineering Dept.
Faculty of Engineering, Alexandria University
6th Hurghada Street, San Stephano
Alexandria, Egypt
Email: 
m.h.karmo...@gmail.com

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Re: [Discuss-gnuradio] Quadrature rate question

[Martin Braun (CEL)]

On Mon, Dec 10, 2012 at 01:05:13PM +0100, Martin Braun (CEL) wrote:
> On Mon, Dec 10, 2012 at 09:44:29PM +1000, Phil wrote:
> > A recent post by Markus Gonser had me intrigued and so I
> > experimented with his grc code. The resulting FM receiver does work
> > but it doesn't quite sound right. My guess is that the quadrature
> > rate is not correct at 705.6kHz. Is this the correct rate and if
> > it's not what should it be?
> 
> That depends. The quadrature rate is the rate of the incoming I/Q sample
> stream. 705.6 kSps seems unusual, though.

Actually, it's 16*44.1kSps, which isn't that unusual. Still, you need to
get that rate at the input.

MB
-- 
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

Dipl.-Ing. Martin Braun
Research Associate

Kaiserstraße 12
Building 05.01
76131 Karlsruhe

Phone: +49 721 608-43790
Fax: +49 721 608-46071
www.cel.kit.edu

KIT -- University of the State of Baden-Württemberg and
National Laboratory of the Helmholtz Association


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Re: [Discuss-gnuradio] Quadrature rate question

[Martin Braun (CEL)]

On Mon, Dec 10, 2012 at 09:44:29PM +1000, Phil wrote:
> A recent post by Markus Gonser had me intrigued and so I
> experimented with his grc code. The resulting FM receiver does work
> but it doesn't quite sound right. My guess is that the quadrature
> rate is not correct at 705.6kHz. Is this the correct rate and if
> it's not what should it be?

That depends. The quadrature rate is the rate of the incoming I/Q sample
stream. 705.6 kSps seems unusual, though.

MB

-- 
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Communications Engineering Lab (CEL)

Dipl.-Ing. Martin Braun
Research Associate

Kaiserstraße 12
Building 05.01
76131 Karlsruhe

Phone: +49 721 608-43790
Fax: +49 721 608-46071
www.cel.kit.edu

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Re: [Discuss-gnuradio] Constructing a signal processing block

[Martin Braun (CEL)]

On Mon, Dec 10, 2012 at 10:23:32AM +, virgil passas wrote:
> I want to create a signal processing block that it will have variable number 
> of
> inputs/outputs AND variable type of inputs/outputs depending the needs of the
> user. (Example1: 3 inputs/ports [complex,double,int] and the same outputs/
> ports. Example2: 4 inputs/ports [double,double,short,complex]  and the same
> outputs/ports.) My problems are: 

OK, to get this straight:
You can have variable number of inputs/outputs (all of what you're
describing is possible), but you CANNOT change that during runtime.

Also, how would you drive this kind of block? The input data type would
have to change, as well.

What *is* quite common is that the block can serve different data types,
which is configured during instantiation. You must have some kind of
check in the constructor, and then pass different io_signatures
depending on your use case.
In the work() function, run the same check again. All the input_items
pointers are void pointers, after all--so you simply cast them to
whatever you set in the constructor.

>  1. How to create an instance of this block with the appropriate size
> (gr.sizeof_double + gr.sizeof_complex is ok?)

You need to return different io_signatures depending on your config.
Read these:
http://gnuradio.org/doc/doxygen/gr__io__signature_8h.html
http://gnuradio.org/redmine/projects/gnuradio/wiki/Tutorials

>  2. In function work() how to define the different type of inputs (every time
> that the block is called the type of inputs will be different) before
> passing them to the function that I want.

See above.

>  3. How to connect in python two or more blocks to a third block.

This is the same as usual, and is covered in the tutorials.

MB

-- 
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

Dipl.-Ing. Martin Braun
Research Associate

Kaiserstraße 12
Building 05.01
76131 Karlsruhe

Phone: +49 721 608-43790
Fax: +49 721 608-46071
www.cel.kit.edu

KIT -- University of the State of Baden-Württemberg and
National Laboratory of the Helmholtz Association


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[Discuss-gnuradio] Quadrature rate question

[Phil]

A recent post by Markus Gonser had me intrigued and so I experimented 
with his grc code. The resulting FM receiver does work but it doesn't 
quite sound right. My guess is that the quadrature rate is not correct 
at 705.6kHz. Is this the correct rate and if it's not what should it be?


A Google search didn't turn up anything that I could plug into my receiver.

--
Regards,
Phil
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[Discuss-gnuradio] Constructing a signal processing block

[virgil passas]

Hi all,

I want to create a signal processing block that it will have variable number of 
inputs/outputs AND variable type of inputs/outputs depending the needs of the 
user. (Example1: 3 inputs/ports [complex,double,int] and the same 
outputs/ports. Example2: 4 inputs/ports [double,double,short,complex]  and the 
same outputs/ports.) My problems are: 
1. How to create an instance of this block with the appropriate size 
(gr.sizeof_double + gr.sizeof_complex is ok?)
2. In function work() how to define the different type of inputs (every 
time that the block is called the type of inputs will be different) before 
passing them to the function that I want.
3. How to connect in python two or more blocks to a third block.

Any thoughts?

Thanks in advance,
Virgilios Passas
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Re: [Discuss-gnuradio] misterious symetrical signal

[nexy_sm]

I have USRP1 equipped with WBX and LFTX and LFRX daughter boards. When want
to use /uhd_cal_rx_iq_balance/ to calibrate my WBX board it won't do that,
it says that calibration is not supported by hardware. I suppose the problem
is uhd wants to calibrate LFRX board, and I don't know how to specify the
oder board.
Any suggestions?

Regards
Nemanja



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[Discuss-gnuradio] [ Calculating the amplitude of a signal source ]

[Ashish Raste]

Hi all,

For calculating the amplitude (assume RMS amplitude) of a signal source, I
first tried to record the received samples (I'm using a vector signal
generator) in a file_sink and then  thought to use it for my calculation.
The frequency of the signal from the signal generator was set to 400M and
the sampling rate of the USRP source block (in GRC) was set to 2M. Have
attached the block diagram below:[image: Inline image 1]

I am able to extract the float (the data type I used) values from the file
but they are too small to be considered as amplitudes at different points
in time i.e the maximum value was 1.03e-09 and minimum was -8.4e-13.

Can anyone please tell me how I can calculate the amplitude of any such
signal in real-time? Is this approach of calculating amplitude the
right oneOR is there any other smarter way to do it?

Thanks and Regards,
-- 
Ashish
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