[Hackrf-dev] transmitting problem

[Peter Shipley]

thank you for the insight.

As you may have guessed, my generated IQ stream was made with a loop
calling sin/cos and timing the transitions to times where I&Q can swap
symmetrically ( without jumping ).
what is then proper method for making phase transitions?

while there is a lot of documentation on what IQ data is,
I've found very little documentation on proper  generation ( trust me, I've
looked)

also do you recommend any references on filtering/post processing?

also, thanks for spotting the data inversion, I'm sure I would have spotted
it after I got it transmitted.
On Jun 28, 2015 08:21, "Mike" <mike at flomp.net> wrote:

> I noticed that the generated sample is quite a lot smaller than the record
> sample - I wonder whether there's a minimum buffer size somewhere that's
> not being hit? Maybe try a larger generated file.
>
> I had a look at the sample files (spectrogram image attached, generated on
> the left and recorded on the right) and noticed that the 0/1 frequencies
> seem to be swapped. Also, it's a fantastic demo of why you need to apply
> filtering to a transmitted signal: the extra vertical bars show the
> harmonics and the horizontal bars show the wideband frequency content from
> the sudden change in frequency.
>
> On 28 June 2015 at 02:43, Peter Shipley <peter.shipley at gmail.com> wrote:
>
>> I am trying to transmit FSK2 at 915Mhz and can't figure out what I am
>> doing wrong or what I am  missing.
>>
>> I am trying to transmit a generated FSK2 signal.
>> (Specs : freq=914973000, sample rate=2400000, FSK2 data with a
>> deviation of 15000 )
>>
>>
>> I can record and transmit a replay without  problems
>> but I can't transmit  my own generated IQ data.
>>
>> the hackrf device does not  transmit anything at all when I send my IQ
>> data
>> (I can demodulate both localy with out error )
>>
>> can someone clue me on what I missed or what is wrong with my IQ data
>>
>>  I have included recorded sample (that will transmit) and and
>> generated sanple (that wont transmit )
>> along with gnuplots of the data.
>>
>>
>> https://drive.google.com/folderview?id=0B9v7L0HOe0FsfklXSFF0WUpIQzE4QUpRUzIzZXlsTUxXUFBPcWtzUGpmSlV3RTRGa1duaTA&usp=sharing
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>>
>
>
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