[Hackrf-dev] HackRF as a function generator

MA mehdideveloper at gmail.com
Sun Nov 22 16:28:02 EST 2015


Ok, I managed to see the output of HackRF with my oscilloscope, but I have
two problems:
1- When I use osmocom_siggen, I see nothing on oscilloscope (are there any
tweaks/tips I should know?)
2- I used a very simple FM transmitter (on 14MHZ) and connected its output
to oscilloscope, but what I see is a pure sinusoidal wave, not an FM
modulated one. A picture and the GRC file are attached.
I have tested this file with 80MHZ and could easily listen it on a FM
radio, so it works and produces something, but I don't know why the output
on oscilloscope is like this.

Best regards
Mehdi

On Sun, Nov 22, 2015 at 2:50 PM, Dominic Spill <dominicgs at gmail.com> wrote:

> On 21 November 2015 at 19:57, MA <mehdideveloper at gmail.com> wrote:
> >
> > Can I connect HackRF's output directly to an oscilloscope? (in TX mode,
> running osmocom_siggen)
> > I was worried whether connecting it (without using an antenna or dummy
> load)
> > would hurt HackRF's output.
>
> I would suggest using a dummy load to be cautious, but I really have
> no experience of connecting HackRF One directly to other equipment.
>
> Mike Ossmann, Jared Boone or anyone else who has tried this can
> probably give a better response as to why you would/wouldn't need to.
>
> Thanks,
>   Dominic
>
> > On Sun, Nov 15, 2015 at 9:20 PM, Dominic Spill <dominicgs at gmail.com>
> wrote:
> >>
> >> On 14 November 2015 at 09:56, MA <mehdideveloper at gmail.com> wrote:
> >> >
> >> > Can I use HackRF as a function generator?
> >>
> >> From a software point of view, it's very easy to accomplish.  If you
> >> want to use GNU Radio you can use the waveform generator block [1]
> >>
> >> > (The only thing I've found is "osmocomm_siggen" and a single page in
> >> > Michael's Recon2014 presentation, under "Baseband Expansion Board"
> >> > title)
> >>
> >> From the hardware side, there is a header on HackRF (P9 on the right
> >> hand side of this image) which allows access to the baseband, giving
> >> you direct access to the output of the DACs (and input to the ADCs).
> >> The "Baseband Expansion Board" would be plugged in to that header to
> >> allow signals to be used without passing through the analogue
> >> front-end.  The expansion board would be used to mix the I and Q
> >> signals (and possibly offer some other features).
> >>
> >> Dominic
> >>
> >> [1]
> >>
> https://gnuradio.org/doc/doxygen/group__waveform__generators__blk.html#gac97c0f42ffb63f1265decceaaeab9177
> >> [2] https://i.imgur.com/og7TGVz.jpg
> >
> >
>
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