[USRP-users] B200 56MHz sample rate

Simon Brown simon at sdr-radio.com
Tue Mar 15 15:11:33 EDT 2016


Marcus,

 

Thanks for the suggestion – I’m using sc16 at the moment. The USB3 is on an
Asus X99-Deluxe Intel X99 (Socket 2011) DDR4 ATX Motherboard, so the chipset
is Intel X99.

 

I’m not too worried at this moment in time – I now know how to get the B200
running at 56MHz, I’ll look at possible bottlenecks later.

 

Simon Brown, GK4ELI
http://sdr-radio.com

 

From: Marcus Müller [mailto:marcus.mueller at ettus.com] 
Sent: 15 March 2016 19:04
To: Simon Brown <simon at sdr-radio.com>; USRP-users at lists.ettus.com
Subject: Re: [USRP-users] B200 56MHz sample rate

 

Hi Simon,



I assume you’re sending 24 bit complex data from the B200?

Well, the default data type is what we name "sc16"; signed complex 16bit,
i.e. 32bit per complex sample (short I, short Q). 
For your case, where no oversampling and in-FPGA decimation happens, using a
sc12 on-the-wire format would be possible, indeed.
Just replace "sc16" by "sc12" where you set up your streamer; I'm not 100%
of your application.

Best regards,
Marcus



On 03/15/2016 07:55 PM, Simon Brown wrote:

Well,

 

That fooled the B200 into offering 56MHz as a sample rate but you’re right –
the controller couldn’t handle it (At least I assume it’s the controller and
not my dodgy software :) ).

 

32MHz streams superbly so I’ll leave that as the maximum for now.

 

I assume you’re sending 24 bit complex data from the B200?

 

Simon Brown, GK4ELI
http://sdr-radio.com

 

From: USRP-users [mailto:usrp-users-bounces at lists.ettus.com] On Behalf Of
Marcus Müller via USRP-users
Sent: 15 March 2016 18:31
To: usrp-users at lists.ettus.com <mailto:usrp-users at lists.ettus.com> 
Subject: Re: [USRP-users] B200 56MHz sample rate

 

You should just set the sampling rate to 56e6, and of course, you'll either
need to leave that unspecified, or specify a master clock rate of 56MHz,
too.
Just a small warning: It's very probable that the USB packet rate will bring
your PC's USB3 controller to its knees. 

Best regards,
Marcus

On 03/15/2016 07:27 PM, Simon Brown via USRP-users wrote:

Hi,

 

While Derek is on holiday, can anyone help me get the 56 MHz bandwidth from
my B200? What’s the trick please – at the moment it’s returning possible
rates up to 16MHz, works well at 32MHz though. I would like to see how good
the returned 56MHz is.

 

Probably just one command somewhere


 

TTFN

 

Simon Brown, GK4ELI
http://sdr-radio.com

 







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