Texas Instruments TRF1500 - Manual (Page 42)

SWRA004A
TRF1500 Integrated Dual-Band RF Receiver User’s Guide 43
High-Band Cascaded: Noise Figure
Control state: 111001
SEE APPENDIX A: TEST BENCH SETUPS
Test setup Figure 22
The cascaded Noise Figure (NF) is measured at the EVM Low
Band IF output port, J21. The measurement is performed using an
HP8970B Noise Figure Meter. The IF output of the mixer is
converted from differential to single ended using a transformer
balun. The noise figure meter requires a special setup and
calibration since the RF source and receive frequencies are
different.
Set up the noise figure meter as follows:
1) Special Function 1.4 sets the noise figure meter to measure
variable IF and fixed LO frequencies.
2) The IF start, stop, and step size frequencies are set to
100MHz, 120MHz, and 5MHz respectively.
3) Set the smoothing to 16 or above.
4) Ensure that the Excess Noise Ratio (ENR) Table on the Noise
Source head in use is entered on the NF meter.
a) On the front panel, press the ENR button.
b) Check the ENR value by pressing the Enter button or enter
the ENR value for each frequency.
c) After entering the ENR for the desired frequency, press the
Frequency button on the front panel to exit.
5) To calibrate the NF Meter:
a) Connect the Noise Source directly to the NF meter; press
the calibration button twice.
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.