Re: Questions on the GNU WiFi GUI with the USRP B210 box

[Marcus D. Leech]

On 06/26/2020 07:06 PM, Silvio Cardero wrote:

On the TX GUI what does tx_ampl adjust and what is a scale of 0-1 mean?

The constellation breaks if I use more than a .3 setting.

That's (I'm guessing, this particular piece of code isn't mine) that it sets the magnitude of samples going into the radio.
  Gnu Radio uses a floating-point representation internally with samples are in the range {-1.0,1.0}, which gets translated
  by device drivers into (very approximately) the max-scaling of whatever D/A (or, A/D in the RX case) is in use by the hardware.
  But keep in mind that it's very approximate, and in an actual transmitter, the output of the D/A is mixed with the LO signal, and
  then amplified.  So combinations of base-band magnitude, and TX RF Gain setting can easily result in non-linear operating
  of analog components--either in the TX direction, the RX direction (you're using a cable) or BOTH.

 

 

On the RX what is LS, LMS, STA, Linear Comb?

 

Silvio Cardero Chief Scientist   520.247.7275 (cell) Web    www.ed2corp.com     Email  Silvio@ed2corp.com 7636 N. Oracle Road Tucson, Az. 85704