Re: [Discuss-gnuradio] Regarding Filtering Aliasing in USRP B210

On 08/05/2014 10:07 PM, Matias wrote:
> We tried to get rid of the aliasing by using a band-pass filter with the
> following parameters:
>
> -Sample Rate: 16MHz
> -Low Cutoff Freq: 856MHz
> -High Cutoff Freq: 864MHz
> -Transition Bandwidth: 1MHz

Hey Matias,

did you put these settings in a GRC-generated filter? I'm asking because
you're using pass-band frequency values, not baseband frequency values.

> But we obtained this error: "IndexError: gr_firdes check failed: 0 < fa <=
> sampling_freq / 2". We later found that lowering the low cutoff frequency
> to 1MHz and the high cutoff frequency to 8MHz (<= sampling_freq / 2), the
> program checks pass but the GUI scope will not show any output. Are we using
> this correctly? Is there perhaps a better way to get rid of the aliasing?

...this would also confirm my suspicion.

M



>
> Thanks,
> Matias Ponce
> CellAntenna Engineer
> CellAntenna Corporation
>
> 12453 NW 44th Street
> Coral Springs, FL 33065
>
> Office: 954-340-7053 ext 10251
> E-mail: mponce@cawireless.com
> Web: http://www.cellantenna.com
>
>
>
> --
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>
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