Texas Instruments TRF1500 - Manual (Page 41)

SWRA004A
42 TRF1500 Integrated Dual-Band RF Receiver User’s Guide
High-Band Cascaded: Image Rejection
Control state: 111001
SEE APPENDIX A: TEST BENCH SETUPS
Test setup Figure 20
Image Rejection is a signal that appears at twice the IF distance
from the desired RF signal, located on the opposite side of the LO
frequency from the desired RF signal. The measurement is
performed using two RF sources and a spectrum analyzer.
1) Set the RF source power (RF P
in
) and the desired RF
frequency (F
RF
) (see Table 4). Connect the RF source to the
EVM RF input port, J20.
2) Set the LO source power (LO P
in
) and the desired LO
frequency (F
LO
)(see Table 4). Connect the LO source to the
EVM LO input port, J12.
3) Set the spectrum analyzer to measure at the IF frequency
(F
IF
)(see Table 4).
4) Connect the EVM IF output port, J21, to the spectrum
analyzer.
5) Measure the output power at the IF frequency (IF P
out
) with the
spectrum analyzer.
6) Set the RF Frequency to F
RF
+ 2 F
IF.
7) Measure the output power at the IF frequency (IF P
out
) with the
spectrum analyzer
8) Calculate the Image Rejection as
Image Rejection =
∆
between the IF output power at (F
RF
)
and the IF output power at F
RF
+ 2 F
IF