MATLAB's USRP documentation (e.g. /commusrp/help/methods/sdru_transmitter/comm.sdrutransmitter.step.html) explains the step function as follows:
stepTransmit signal and control data to USRPTM board
Syntaxstep(H,X)
UNDER = step(H,X)
step(H,X,FC)
step(H,X,LO)
step(H,X,GAIN)
step(H,X,INTERP)
Descriptionstep(H,X) transmits signal and control
data to a USRPTM board using User Datagram
Protocol (UDP) packets. The input signal, X, is a
column vector of double values.
What range has X--what are its minimum and maximum values?
Thanks,
Stan

Hi Stan,

The MATLAB code for comm.SDRuTransmitter does not perform any range checking on its inputs.  So the object itself will accept any double values.

Any range checking would be performed by the underlying UHD code.

Best,

Mike

From: Stan Gamla [mailto:cystrin@hotmail.com]
Sent: Sunday, March 24, 2013 4:54 PM
To: USRP-USERS Ettus
Cc: Darel Linebarger; Marc Erickson; Ethem Sozer; Mike McLernon
Subject: USRP :: MATLAB's comm.SDRuTransmitter

MATLAB's USRP documentation (e.g. /commusrp/help/methods/sdru_transmitter/comm.sdrutransmitter.step.html) explains the step function as follows:

step

Transmit signal and control data to USRPTM board

Syntax

step(H,X)
UNDER = step(H,X)
step(H,X,FC)
step(H,X,LO)
step(H,X,GAIN)
step(H,X,INTERP)

Description

step(H,X) transmits signal and control data to a USRPTM board using User Datagram Protocol (UDP) packets. The input signal, X, is a column vector of double values.

What range has X--what are its minimum and maximum values?

Thanks,

Stan