Texas Instruments TRF1500 - Manual (Page 43)

SWRA004A
44 TRF1500 Integrated Dual-Band RF Receiver User’s Guide
a) Special Function 34.1 turns on the loss compensation
factor.
b) Special Function 34.2 is used to enter the loss before the
DUT.
c) Special Function 34.3 is used to enter the room
temperature in Kelvin (300
°
K).
d) Special Function 34.4 is used to enter the loss after the
DUT.
e) Special Function 34.0 is used to turn off the loss
compensation factor.
The noise figure is measured as follows:
7) Connect the noise source directly to the EVM RF input port,
J20.
a) A circulator between the noise source and RF input port
may help minimize any mismatches between the EVM
board and test equipment.
8) Connect the LO source to the EVM LO input port, J12.
a) Set the LO source at the nominal power and frequency
(See Table 4).
b) Each LO frequency being tested is entered in the Noise
figure meter by using Special function 3.1. If the source
has excessive broad band noise, a filter at the LO port,
J12, may be necessary to eliminate the broad band noise
during testing.
9) Connect the EVM IF output port, J21, to the noise figure meter
input port.
a) A bandpass or low pass filter may be necessary on the IF
port to eliminate the LO signal interference and get an
accurate noise measurement.
10) Measure the Noise Figure.
High-Band Cascaded: RF Input Return Loss
Control state: 111001
The cascaded input return loss of the high band is measured at
the high band RF input port, J20. The measurement is performed
using a network analyzer.
Set up the network analyzer as follows to measure the RF input
return loss: