[Hackrf-dev] FM Modulating external MPX Signal

[veso266 at gmail.com]

Thats where the problem start I dont know how to feed two jack cables into one jack sink



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On Sun, Sep 6, 2015 at 11:47 PM, Karl Koscher <supersat at cs.washington.edu>
wrote:

> GNU Radio supports JACK as an audio source and sink. You can set the
> default audio interface with a config file (see
> http://gnuradio.org/redmine/projects/gnuradio/repository/revisions/master/entry/gr-audio/lib/gr-audio.conf
> for an example).
> You probably don't want to use the WBFM block since it will apply
> preemphasis, which stereotool should already do, and may also apply a low
> pass filter, which would effectively destroy the encoding that stereotool
> does.
> Instead, you should just use the standard FM Modulation block. It will ask
> for a "sensitivity" parameter, but looking at the WBFM block source, it
> seems like you should just set it to 2 * math.pi * max_dev / quad_rate,
> where max_dev is 75 kHz and quad_rate is the output symbol rate. Note that
> the output symbol rate of the block is the same as the input symbol rate,
> so you'll probably want a rational resampler before the FM modulator to
> take the signal from 192 kHz to whatever sample rate you feed in to the
> HackRF (you'll probably want to use something like 2112 ksps, which is the
> smallest integer multiple of 192 ksps that's above the 2 msps minimum of
> the HackRF... 1920 ksps may also work?)
> On Fri, Sep 4, 2015 at 10:17 AM, Mitja kocjančič <veso266 at gmail.com> wrote:
>> Hi anyone know How I can FM Modulate External MPX SIgnal?
>>
>> I am using MPY Signal Generator called Stereo Tool:
>> http://www.stereotool.com/
>>
>> the program uses two Jack Audio Cables (left and right) and it outputs
>> 192khz MPX Generated Audio over it. and there where problem starts I know
>> that I need 288k sample rate and WBFM Block needs 288k Quadrature rate and
>> 192 Audio rate but I don't know how to link GNU Radoi with jack
>> Is there any JackAudio to Linux standart Pipe sender or anything like that
>> So I can feed MPX Data from Stereo Tool to it?
>>
>> PS: How would GNU Radio flowgraph look like (I would probably need some
>> Rational Resampler or something like that.
>>
>> I know there is gr-rds Block Package but I would like to use Stereo Tool
>> for RDS because It has even RT+ and it can read RT details from external
>> file
>>
>>
>>
>> Thanks for Anwsering and Best Regards
>>
>> _______________________________________________
>> HackRF-dev mailing list
>> HackRF-dev at greatscottgadgets.com
>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>
>>
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