Re: [Discuss-gnuradio] UHD I/O Data Types

[Arya Santini]

By a real signal, I mean a signal like a real valued sinusoid. Say in
a grc graph, I have this:  signal generator (sine, float o/p) ---->
float to short converter ----> usrp sink (short i/p). In this example,
I'm inputting a stream of shorts representing a pure sine wave to the
usrp module. I wanted to ask how I can do this exactly when I call the
send() to the UHD inside a C++ program? (an array of float values
represent the pure sinusoid, which is the waveform I wish to
transmit).

Arya

On Wed, Apr 6, 2011 at 10:47 PM, Josh Blum <address@hidden> wrote:
>
>
> On 04/06/2011 08:42 PM, Arya Santini wrote:
>> Hello..
>>
>> The I/O types defined in the uhd::io_type_t class lists 4 COMPLEX
>> types and a CUSTOM type. What I/O type should I specify in the call to
>> send()/recv() if my baseband signal is real and not complex, say I'm
>> transmitting from a file containing real samples of float type. How is
>> a sample type of real float or real short interpreted and/or converted
>> by the UHD library to shorts over the wire?
>>
>
> I think this is a misunderstanding. A complex baseband signal represents
> 1/fs bandwidth of spectral content which the USRP will modulate to the
> center frequency -> fc.
>
> To have a "real" signal is to leave half of your spectrum undefined. Is
> it symmetric about fc? or is it really a complex signal centered at fc+fs/4?
>
> -Josh
>
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>