Hi Marcus,
Yes, I added a resampler to upsample by 250kHz and scaled the IQ samples by
dividing it with 2**16, since each IQ is of 16bit.
With this it started to work.
Now, I want to keep changing the IQ file at run time. I have a lot of IQ files
in current folder, which I want to use for transmission
for certain time say after running one IQ file for 2 min, change the IQ file,
this should keep continuing.
I had a look at the python code grc generated, and it basically creates a class
which initializes with the specified IQ file and creates the connection
and runs.
How do I change this python code so that it can loop over all IQ files in the
folder, any example python code available ?
Please help me in setting it up.
-ben
________________________________
From: USRP-users <usrp-users-boun...@lists.ettus.com> on behalf of Marcus
Müller via USRP-users <usrp-users@lists.ettus.com>
Sent: Wednesday, March 21, 2018 2:10 AM
To: Marcus D. Leech; usrp-users@lists.ettus.com
Subject: Re: [USRP-users] IQ transmission using grc
Hi ben,
also, no USRP can directly deal with a sampling rate as low as 48 kHz –
you'll first have to resample to a rate that your USRP can deal with.
In case of the N210, these frequencies are integer fractions of 100 MHz
i.e. 100 MHz / N, with the restriction that N be an integer 3 < n <=
128 , an even integer 2 < n <= 256 or an integer multiple of 4 <= 512.
tx_samples_from_file can't resample – you should have been getting UHD
warnings about impossible sampling rates; your IQ file has simply been
played back at a higher rate.
Best regards,
Marcus
On Tue, 2018-03-20 at 12:58 -0400, Marcus D. Leech via USRP-users
wrote:
> On 03/20/2018 12:37 PM, Benny Alexandar via USRP-users wrote:
> > Hi,
> >
> > I have an IQ file sampled at 48kHz and want to transmit through gnu
> > radio. The IQ samples are each 16bit, and stored interleaved in a
> > file
> > ie, IQIQIQIQ... I 16 bit and Q 16bit
> >
> > I tried creating a grc using iShort to Complex block and send to
> > USRP sink block (usrp n210), but the signal received is distorted.
> > Do I need to convert the short values into float -1.0 to +1.0
> > before transmission. Please help in resolving it.
> >
> > I want to use it only through grc and not to use
> > tx_samples_from_file which does the same.
> >
> > -ben
> >
> You'll need to scale your samples into {-1.0,1.0}
>
>
>
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