USRP bandwidth and FIFOs

GNU Radio
1

Hello!

I have two questions about USRP:

  1. It is stated on
    http://www.comsec.com/wiki?UniversalSoftwareRadioPeripheral that USRP
    can sustain 32 megabytes per second over USB2.0.
    I’m about to build MIMO 2 antenna transmitter. As I and Q each occupy
    16 bits, for two-antenna sample it will require (16*2) * 2 = 64 bits
    or 8 bytes. As a result I can get 32 / 8 = 4 mega samples per second
    and from Nyquist theorem only 2 MHz wide signals could be transmitted.

Please advise whether my reasonings are right.

  1. What are the TX and RX FIFO buffers’ sizes on the board?

Thanks in advance.

2

Andrey A wrote:

and from Nyquist theorem only 2 MHz wide signals could be transmitted.

4 MS/s COMPLEX gives a 4 MHz nyquist band, since it is complex samples.

Please advise whether my reasonings are right.

  1. What are the TX and RX FIFO buffers’ sizes on the board?

2K lines, IIRC

Matt

3

Matt, thank you for quick reply!

or 8 bytes. As a result I can get 32 / 8 = 4 mega samples per second
and from Nyquist theorem only 2 MHz wide signals could be transmitted.

4 MS/s COMPLEX gives a 4 MHz nyquist band, since it is complex samples.

Please advise whether my reasonings are right.

  1. What are the TX and RX FIFO buffers’ sizes on the board?

2K lines, IIRC

  1. Does 2K lines mean 2048 bits?

  2. I noticed the HMC174MS8 switch on the tx/rx path. Does it mean what
    Time Division Duplex is in use? We transmit and receive signals in
    different time moments?

Thank you!