[USRP-users] Twin RX Bandwidth Requirements

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[USRP-users] Twin RX Bandwidth Requirements

Martin Braun via USRP-users

Hello,

 

What is the best data-link (PCI-E, 10GbE) to use with an X3X0 running two Twin RX receivers at full rate? That setup would be two daughterboards streaming a total of 4 channels of 80MS/s floating-point complex data back to a computer. The pages for both the 10GbE card and PCI-E card say they support 200MS/S in full-duplex mode. Can they run at 320MS/s in one direction?

 

Thanks,

 

Kevin Rigney

 


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Re: [USRP-users] Twin RX Bandwidth Requirements

Martin Braun via USRP-users

Hi Kevin,

go for 10GbE for high throughput. PCIe is most recommendable for LabVIEW usage. Also, 10GE connectivity is far more flexible – you can use anything that does 10GBase with SFP+ connectors – for example, mouser.com has a small selection of cheap Amphenol FCI 10GBE cables in stock, and you can use any 10GBase-SR, -LR,... fiber optics SFP+ transceiver (and: if you're on a budget: these can often be had as surplus equipment!) for longer distances.

320MS/s need 320 MS/s * 32b/S = 10.24 GB/s > 10GB/s == 10GE wire speed. But:

with UHD 3.10.0.0 dual-10GE support was added, but I've never tried it myself so far, but what I found out (thanks, Nate!) was:

If you specify a device address string, you'd use "addr=192.168.30.2,second_addr=192.168.40.2" (assuming these were your device's addresses)and then you'd be able to use two 10GE connections in parallel.

Best regards,

Marcus


On 10/03/2016 08:10 AM, Rigney, Kevin E via USRP-users wrote:

Hello,

 

What is the best data-link (PCI-E, 10GbE) to use with an X3X0 running two Twin RX receivers at full rate? That setup would be two daughterboards streaming a total of 4 channels of 80MS/s floating-point complex data back to a computer. The pages for both the 10GbE card and PCI-E card say they support 200MS/S in full-duplex mode. Can they run at 320MS/s in one direction?

 

Thanks,

 

Kevin Rigney

 



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Re: [USRP-users] Twin RX Bandwidth Requirements

Martin Braun via USRP-users

Ah, I was just pointed to something (thanks for that) the fact that the ADCs always run at 200MS/s, and currently, we have no rational resampler, only a DDC chain with a normal decimation, i.e. you can't have 4x 80MS/s, but 4x 100MS/s works!

Best regards,
Marcus


On 10/03/2016 10:07 AM, Marcus Müller wrote:

Hi Kevin,

go for 10GbE for high throughput. PCIe is most recommendable for LabVIEW usage. Also, 10GE connectivity is far more flexible – you can use anything that does 10GBase with SFP+ connectors – for example, mouser.com has a small selection of cheap Amphenol FCI 10GBE cables in stock, and you can use any 10GBase-SR, -LR,... fiber optics SFP+ transceiver (and: if you're on a budget: these can often be had as surplus equipment!) for longer distances.

320MS/s need 320 MS/s * 32b/S = 10.24 GB/s > 10GB/s == 10GE wire speed. But:

with UHD 3.10.0.0 dual-10GE support was added, but I've never tried it myself so far, but what I found out (thanks, Nate!) was:

If you specify a device address string, you'd use "addr=192.168.30.2,second_addr=192.168.40.2" (assuming these were your device's addresses)and then you'd be able to use two 10GE connections in parallel.

Best regards,

Marcus


On 10/03/2016 08:10 AM, Rigney, Kevin E via USRP-users wrote:

Hello,

 

What is the best data-link (PCI-E, 10GbE) to use with an X3X0 running two Twin RX receivers at full rate? That setup would be two daughterboards streaming a total of 4 channels of 80MS/s floating-point complex data back to a computer. The pages for both the 10GbE card and PCI-E card say they support 200MS/S in full-duplex mode. Can they run at 320MS/s in one direction?

 

Thanks,

 

Kevin Rigney

 



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Re: [USRP-users] Twin RX Bandwidth Requirements

Martin Braun via USRP-users
On 10/03/2016 02:00 PM, Marcus Müller via USRP-users wrote:

Ah, I was just pointed to something (thanks for that) the fact that the ADCs always run at 200MS/s, and currently, we have no rational resampler, only a DDC chain with a normal decimation, i.e. you can't have 4x 80MS/s, but 4x 100MS/s works!

Best regards,
Marcus

I'd rather like to meet the computer that can handle 400Msps of this stuff, and "do useful things" for various values of "useful".

In fact, the not-for-profit that I'm in the middle of creating would love a handful :)



On 10/03/2016 10:07 AM, Marcus Müller wrote:

Hi Kevin,

go for 10GbE for high throughput. PCIe is most recommendable for LabVIEW usage. Also, 10GE connectivity is far more flexible – you can use anything that does 10GBase with SFP+ connectors – for example, mouser.com has a small selection of cheap Amphenol FCI 10GBE cables in stock, and you can use any 10GBase-SR, -LR,... fiber optics SFP+ transceiver (and: if you're on a budget: these can often be had as surplus equipment!) for longer distances.

320MS/s need 320 MS/s * 32b/S = 10.24 GB/s > 10GB/s == 10GE wire speed. But:

with UHD 3.10.0.0 dual-10GE support was added, but I've never tried it myself so far, but what I found out (thanks, Nate!) was:

If you specify a device address string, you'd use "addr=192.168.30.2,second_addr=192.168.40.2" (assuming these were your device's addresses)and then you'd be able to use two 10GE connections in parallel.

Best regards,

Marcus


On 10/03/2016 08:10 AM, Rigney, Kevin E via USRP-users wrote:

Hello,

 

What is the best data-link (PCI-E, 10GbE) to use with an X3X0 running two Twin RX receivers at full rate? That setup would be two daughterboards streaming a total of 4 channels of 80MS/s floating-point complex data back to a computer. The pages for both the 10GbE card and PCI-E card say they support 200MS/S in full-duplex mode. Can they run at 320MS/s in one direction?

 

Thanks,

 

Kevin Rigney

 



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Re: [USRP-users] Twin RX Bandwidth Requirements

Martin Braun via USRP-users

Heh, that's pretty through, though I've seen people do 2x200MS/s at least running a FFT display, and I think there was some demo that actually used quad-channel full-rate TwinRX; hopefully Wan can chime in on what machine that was. "Useful" actually is pretty hard to define ;), a FFT display might or might not fulfil that requirement.

But, yes. You'll need something with quite a few cores, something whose PCIe architecture is optimized for high-throughput network data, you'll need the CPU cores to run pretty fast, and even then, there'll be a lot of hand-tweaking involved until you get the most out of it. However, I think what we tell most customers is that you first verify operationality, then you use a much lower sampling rate to prototype, then you figure out the bottlenecks, and then you solve these and scale up.

So, the problem is that you've already identified that bottleneck. I'll set up a new dev machine pretty soon (hopefully), and I plan to report back on that, and the issues/solutions involved.

Cheers,

Marcus


On 10/03/2016 11:09 AM, Marcus D. Leech via USRP-users wrote:
On 10/03/2016 02:00 PM, Marcus Müller via USRP-users wrote:

Ah, I was just pointed to something (thanks for that) the fact that the ADCs always run at 200MS/s, and currently, we have no rational resampler, only a DDC chain with a normal decimation, i.e. you can't have 4x 80MS/s, but 4x 100MS/s works!

Best regards,
Marcus

I'd rather like to meet the computer that can handle 400Msps of this stuff, and "do useful things" for various values of "useful".

In fact, the not-for-profit that I'm in the middle of creating would love a handful :)



On 10/03/2016 10:07 AM, Marcus Müller wrote:

Hi Kevin,

go for 10GbE for high throughput. PCIe is most recommendable for LabVIEW usage. Also, 10GE connectivity is far more flexible – you can use anything that does 10GBase with SFP+ connectors – for example, mouser.com has a small selection of cheap Amphenol FCI 10GBE cables in stock, and you can use any 10GBase-SR, -LR,... fiber optics SFP+ transceiver (and: if you're on a budget: these can often be had as surplus equipment!) for longer distances.

320MS/s need 320 MS/s * 32b/S = 10.24 GB/s > 10GB/s == 10GE wire speed. But:

with UHD 3.10.0.0 dual-10GE support was added, but I've never tried it myself so far, but what I found out (thanks, Nate!) was:

If you specify a device address string, you'd use "addr=192.168.30.2,second_addr=192.168.40.2" (assuming these were your device's addresses)and then you'd be able to use two 10GE connections in parallel.

Best regards,

Marcus


On 10/03/2016 08:10 AM, Rigney, Kevin E via USRP-users wrote:

Hello,

 

What is the best data-link (PCI-E, 10GbE) to use with an X3X0 running two Twin RX receivers at full rate? That setup would be two daughterboards streaming a total of 4 channels of 80MS/s floating-point complex data back to a computer. The pages for both the 10GbE card and PCI-E card say they support 200MS/S in full-duplex mode. Can they run at 320MS/s in one direction?

 

Thanks,

 

Kevin Rigney

 



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