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Re: [Discuss-gnuradio] Stuck at WBFM Project :
From: |
Cinaed Simson |
Subject: |
Re: [Discuss-gnuradio] Stuck at WBFM Project : |
Date: |
Sun, 13 Aug 2017 13:44:44 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux i686; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 |
On 08/13/2017 09:22 AM, Andrew Rich wrote:
> I though decimination was throwing away samples
>
> Like decimination of 4 is chuck away every 4 th sample
>
> Dunno what does it mean
>
> Can u up resample ?
Yes, it's called interpolation.
>
> And does it have to be a multiple ?
For the rational resampler, it needs to be a rational ratio of the
interpolation and decimation - which is determined by the flowgraph.
-- Cinaed
>
> A
>
> Sent from my iPhone
>
> On 14 Aug 2017, at 2:12 am, Ash SDR <address@hidden
> <mailto:address@hidden>> wrote:
>
>> Thanks everyone and sorry , I couldn't reply you all for inputs you
>> gave me. I apologies for that...
>>
>> For Now , I kept aside the WBFM project which I asked questions on
>> and working on the Guided Tutorials from GNU Radio and also tutorials
>> from greatScott gadgets video series.
>>
>> I have a dumb question about Rational Resampler... Here is the
>> snapshot from tutorials website..
>>
>> As far as I understand , the Rational resampler modifies the sampling
>> rate of the incoming signal based on Interpolation (or) decimation
>> factor.... Is it something like this
>>
>>
>> *If my incoming Signal is of 10KHz with Sampling Rate of 50 KHz ,
>> Rational Resampler (Interpolation : 4 , Decimation : 1) gives me the
>> output as signal of 10KHz and Sample Rate of 50*4 = 200 KHz
>> ??????*
>>
>> Am I Interpreting it correctly... ??????
>>
>> If thats the case , In the following snapshot , Signal of 1KHz of
>> 48KHz Sample rate is interpolated by factor 4 , Then Output Sampling
>> Rate should be 48*4 = 192KHz which is much higher than the Required
>> Nyquist rate , But the Frequency sink block shows frequency component
>> at 0.25 Hz... Is it because of the "samp_rate" variable set in QT GUI
>> Frequency Sink..
>>
>> I am also playing around with "samp_rate" block in QT Frequency GUI
>> Sink... If i remove rational resampler and just pass on the signal of
>> 1Khz with 48Khz sampling rate in a QT GUI Frequency sink of
>> samp_rate/4 , it outputs the signal as 0.25KHz ///. why so >
>>
>>
>> Please let me know If i am interpreting it correctly as THIS IS VERY
>> IMPORTANT FOR ME TO UNDERSTAND..
>>
>> Thanks
>> Ash
>>
>>
>>
>> tutorial_two_4.pngresampling_output.png
>>
>> On Tue, Aug 8, 2017 at 4:41 PM, Cinaed Simson <address@hidden
>> <mailto:address@hidden>> wrote:
>>
>> On 08/07/2017 07:55 PM, Ash SDR wrote:
>> > Hello Everyone ,
>> >
>> > I am a GNU Radio beginner trying to implement Wideband FM Project and
>> > transmit it to my FM receiver at a very lower power. I am choosing a
>> > frequency in a FM band such that my receiver is not picking anything
>> > from that station/..
>> >
>> > Attached is GRC file which i am working on .and the music file which i
>> > am trying to transmit..
>> >
>> > Can anyone please tell me where I am messing up ?
>>
>> Remove the first rational resampler. Set your audio rate to 48000 Hz,
>> and quadrature rate 192000 Hz.
>>
>> In the second re-sampler set the interpolation to 8000000 Hz and the
>> decimation to 192000 Hz.
>>
>> I'm going to guess you're using the HackRF based on your default
>> values
>> (except for the transmit RF gain which should be 1.)
>>
>> I strongly recommend you spend some time on the going through the
>> tutorials at
>>
>> http://www.greatscottgadgets.com/sdr
>> <http://www.greatscottgadgets.com/sdr>
>>
>> and learn something about your hardware and how to build WBFM receiver
>> befor you try to transmit.
>>
>> -- Cinaed
>>
>>
>>
>>
>> >
>> >
>> > As a beginner , my learning curve is from implemented projects ,
>> > University lectures which are available on-line .. This one is from a
>> > book which i am using to get basic understanding ..
>> >
>> >
>> > Thanks
>> > Ash
>> >
>> >
>> > _______________________________________________
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>> > address@hidden <mailto:address@hidden>
>> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>> <https://lists.gnu.org/mailman/listinfo/discuss-gnuradio>
>> >
>>
>>
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- [Discuss-gnuradio] Stuck at WBFM Project :, Ash SDR, 2017/08/07
- Re: [Discuss-gnuradio] Stuck at WBFM Project :, Andrew Rich, 2017/08/07
- Re: [Discuss-gnuradio] Stuck at WBFM Project :, Marcus Müller, 2017/08/08
- Re: [Discuss-gnuradio] Stuck at WBFM Project :, Robert McGwier, 2017/08/08
- Re: [Discuss-gnuradio] Stuck at WBFM Project :, Cinaed Simson, 2017/08/08
- Re: [Discuss-gnuradio] Stuck at WBFM Project :, Ash SDR, 2017/08/13