Texas Instruments TRF4900, User Manual, Page: 39 / 45

Testing of Transmitter
3-12
Step 3: Spectrum Analyzer Setup and Clock Offset Procedure
Setup the spectrum analyzer to observe the following:
Figure 3−7. Spectrum Analyzer
Clock Offset Procedure
1) Use the test setup as shown in Figure 3−4 and transmitter software setup
shown in Figure 3−5 and Figure 3−6.
2) Observe the frequency reading on the frequency counter.
3) Subtract 915.000000 MHz from the frequency counter reading.
4) Enter the difference value in the Freq. Error box in the main program
screen as shown in Figure 3−8.
5) Note: If the difference value is negative, enter – sign, followed by the differ-
ence value.
Example: Frequency counter reading is 914.996000 MHz
Subtracting 915.000 MHz from 914.996 MHz will yield
a difference of –4000 Hz. This difference is entered in the Freq. Error
block as −0.004 MHz (see Figure 3−8).
6) Press the Update CLK button on the main program screen.
7) Verify that clock frequency is updated as shown in Figure 3−9.
8) Pressing the Update CLK button twice clears the frequency offset.