Question

A transmitter generates a 15-dBm signal and is connected to an antenna using a cable that introduce 2 dB of loss. The cable has two connectors, one at each end, that intro-duce a loss of 2 dB each. What is the signal level at the input of the antenna in dBm and milliwatts?

Answer 1

Answer:

9 dBm or 7.94 mW

Explanation:

As per the question:

Signal generated by the transmitter, $x_{T}$ = 15 dBm

Loss by the antenna, L = 2 dB

No. of connectors, n = 2

Loss by each connector, l = 2 dB

Now,

The signal level at the input of the antenna:

$P = x_{T} - L - nl = 15 - 2 - 2\times 2 = 9\ dBm$

Now, the signal level at the input in milliwatt:

$P = \frac{10^{\frac{P(in\ dBm)}{10}}}{1000}$

$P = \frac{10^{\frac{9}{10}}}{1000} = 7.94\ mW$