Question 9.2: For a signal measurement of -42 dBm, a noise measurement of ......
For a signal measurement of -42 dBm, a noise measurement of 16 dBrnc, and a -40-dBm TLP, determine
a. Signal level in dBrnc.
b. Noise level in dBm.
c. Signal level in dBmO.
d. signal-to-noise ratio in dB. (For the solutions, refer to Figure 4.)
a. The signal level in dBrnc can be read directly from the chart shown in Figure 4 as 48 dBrnc. The signal level in dBrnc can also be computed mathematically as follows:
-42 dBm – (-90 dBrn) = 48 dBrnc
b. The noise level in dBm can be read directly from the chart shown in Figure 4 as -74 dBm. The noise level in dBm can also be calculated as follows:
-90 + 16 = -74 dBm
c. The signal level in dBmO is simply the difference between the actual signal level in dBm and the TLP or 2 dBmO as shown in Figure 4. The signal level in dBmO can also be computed mathematically as follows:
-42 dBm – (-40 dBm) = -2 dBmO
d. The signal-to-noise ratio is simply the difference in the signal power in dBm and the noise power in dBm or the signal level in dBrnc and the noise power in dBrnc as shown in Figure 4 as 32 dB. The signal-to-noise ratio is computed mathematically as
-42 dBm – (-74 dBm) = 32 dB
or 48 dBrnc – 16 dBrnc = 32 dB