Re: [Discuss-gnuradio] undocumented SBX behavior

[Activecat]

Dear Marcus,

At the receiver USRP, does the SBX daughtercard have any mechanism of phase-lock-loop (PLL) ?

I guess the daughtercard should have it because PLL is essential for quadrature downconversion.

Please advise, thanks.

Regards,

activecat

On Sat, Jan 11, 2014 at 1:19 PM, Marcus Leech <address@hidden> wrote:

No, it means that the upconverter is a direct-conversion, quadrature upconverter that produces a real output from the complex baseband and the quadrature local oscillator on the SBX.

On Fri, Jan 10, 2014 at 9:53 PM, Activecat <address@hidden> wrote:

Dear Marcus,

When using GRC, the USRP sink (for N210 with SBX daughtercard) receives complex input.

This means both I and Q data are fed into the USRP from the PC.  Then the I and Q data are sent to the SBX after DUC.

If SBX just perform plain analog upconversion, does it mean that I and Q are upconverted to different carrifer frequencies?

Please advise, thanks.

Regards,

activecat.

 

On Wed, Jan 1, 2014 at 12:17 AM, Marcus Leech <address@hidden> wrote:

The SBX card is an analog upconverter.  It takes your baseband signal, in this case, a pure 5kHz tone, and mixes it

  with a 500Mhz (in this example) carrier, and produces a 500.005Mhz carrier to the antenna.

 

On Tue, Dec 31, 2013 at 1:09 AM, Activecat <address@hidden> wrote:

Dear Sir,

I run this command with SBX daughterboard on N210:

 /usr/local/lib/uhd/examples/tx_waveforms  --freq 500e6  --wave-type SINE   --wave-freq 5e3  --rate 10e6

What is performed at the SBX, does it multiply (Frequency Modulation) the 5kHz SINE wave with the 500MHz carrier frequency ..?

Thanks.

Regards,

address@hidden