Re: [Discuss-gnuradio] DBSRX filter efficiency?

[Eric Blossom]

On Mon, May 18, 2009 at 07:11:43PM +0200, Andreas Bogk wrote:
> Eric Blossom wrote:
>> Hi Andreas!  Welcome!
>>   
>
> Thanks! :)
>
>> Try turning the Rx gain down.
>>   
>
> Been there, done that.  It doesn't get rid of the images.
>
>> The datasheets should be on Maxim's site, though I think they're
>> discontinuing the part.  If you can't locate them, let me know and
>> I'll see if I can't find one for you.
>>   
> I can't find them, and googling for MAX211x only brings me to Gnuradio  
> related information.  Is there a magic part number I need to know? I'd  
> appreciate the datasheets,

OK, I'll look for them later on today.

> or alternatively the information that the  
> filters are indeed in the chip and not tunable.

The chip has a controllable IF-filter bandwidth.  It can be controlled
using the set_bw method on the daugherboard subdevice.  Pass it the
desired bandwith in Hz.  The DBSRX code will accept a value between 1e6 and
33e6, though the chip's only spec'd down to 4e6.  By default we're
running it wide open (33e6).

Eric