[Hackrf-dev] HackRF as a function generator

[Dominic Spill]

On 22 November 2015 at 21:28, MA <mehdideveloper at gmail.com> wrote:
>
> 1- When I use osmocom_siggen, I see nothing on oscilloscope (are there any
> tweaks/tips I should know?)

I've never used it, but could you share the command line arguments
that you used?
Do you see any change at all when you change the parameters?

> 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 see that this works for you, but have you tried something simpler?
Perhaps based on the one here:
http://wiki.opendigitalradio.org/Simple_FM_transmitter_using_gnuradio

> I have tested this file with 80MHZ and could easily listen it on a FM radio,
> so it works and produces something

Is the only thing that you change between the 80MHz/14MHz runs the
frequency in the osmocom sink?


> 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
>> >
>> >
>
>