EXTENSION COURSE OF THE US ARMY SIGNAL SCHOOL
LESSON SOLUTIONS
SIGNAL SUBCOURSE ............................. Telephone System Characteristics
LESSON 2 ..................................... Network Losses and Gains.
1. b--para 2-1d(5), example 1
Attenuator loss = 35 db - 27 db = 8 db.
2. b--para 2-2a, fig. 2-4
The power ratio represented by 3 db is 1/2 or 2/1.
Since level drops 3 db
to cutoff frequency, 1/2 of 8 mw is 4 mw.
3. a--para 2-2b
4. c--para 2-2b, table II
5. a--para 2-2b, table II
6. a--para 2-2d, example 2; fig. 2-1
The power level of +3 dbm is 2 mw. Since each channel signal is 1/4 of
that total power, the power level in each signal is 2/4, or 1/2 mw.
7. d--para 2-1c
8. c--para 2-1f
9. c--para 2-1d, 2-3c
The 20-db loss in the attenuator drops the signal level to -32 dbm. The
10-db loss in the equalizer drops the signal level to -42 dbm.
The 42-db
fixed-gain amplifier raises the level to 0 dbm.
The 6-db pad reduces the
signal level to -6 dbm.
In summation, the total loss is 36 db and the
amplifier gain is 2 db, making the overall circuit gain 6 db. With the input
signal of -12 dbm and circuit gain of 6 db, the final output level is -6 dbm.
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