Re: [Discuss-gnuradio] Questions about synchronization and modulation in benchmark

Check the source code of costas loop and Mueller Mueller clock recovery blocks. They have the link to the reference papers used for the implementation.

Regarding your bpsk/dbpsk question. There is a differential encoder block in the transmit_path of this modulator. Remove this from the connect path and you will get bpsk.

Thanks,
Mir

On Sun, Jan 31, 2010 at 2:54 AM, Timothy Lawrence Sitorus <timothy.l.sitorus@gmail.com> wrote:

Hi Adib

Thanks for the reply.

I check it in the net and download it. I don't know about costas loop and clock recovery in detail. may I know how they they estimate frequency offset, and recover it?
as far as I know,  they are using gr.quadrature_demod_cf(1) & and subtract it using gr.single_pole_iif_filter_ff(alpha) for frequency offset?is it right?

Tim

On Sun, Jan 31, 2010 at 4:03 PM, adib_sairi <adib_sairi@yahoo.com> wrote:

there is some work from Thomas Schmid which modulate and demodulate O-QPSK
which mean for IEEE802.15.4 standard.. you can search and download the code
online. good luck..

Adib

Timothy Lawrence Sitorus wrote:
>
> HI all,
>
> Please anyone help me.
>
> Is there anyone succeeded to modulate qpsk, even frequency offset occurs?
>
>
> Best Regards,
> Tim
>

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