Texas Instruments TRF1500 - Manual (Page 28)

SWRA004A
TRF1500 Integrated Dual-Band RF Receiver User’s Guide 29
b) Next, press the Noise Figure and Gain Button. The
corrected LED just above the button should be lit.
c) Calibration is complete. Enter the desired IF frequency to
measure.
Next, the external equipment Loss is considered (RF cable,
Transmission line, filter and circulator).
6) The losses are entered in the Noise Figure Meter by using
special function 34.x.
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,
J10.
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 3).
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, J11, 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.