Lesson 2/Learning Event 5
j. Listing of characteristics. Lettered items in the CHARACTERISTICS
column of table 2 indicate the name of a test that the circuit conditioner
must perform.
k. Practical
applications
of
frequency
response
characteristic.
Parameters of frequency response give the circuit conditioner a valuable
tool for circuit analysis and adjustment of corrective equipment.
The
frequency response characteristic is listed under parameters in terms of
decibel loss either greater than (+) or less than (-) the loss at 1004 Hz.
The level reflects the opposite relationship; that is, the higher the loss
the lower the level. Conversely, the lower the loss, the higher the level.
EXAMPLE 1.
In the S1 parameter, the frequency response characteristic
should not exceed the range of 2 dB less loss (-) at 0.3
kHz or 6 dB more loss (+) at 3.0 kHz than the loss at 1.04
kHz.
EXAMPLE 2.
Assume that the output level of the circuit at 1.04 kHz is
-2 dBm.
What are the measured levels at 0.3 and 3.0 kHz
for parameter S1?
Less loss is equivalent to a higher
level, and greater loss is equivalent to a lower 1.04 kHz,
so the level will be 2 dB higher than -2 dBm, or 0 dBm. On
the other hand, at 3.0 kHz there will be 6 dB more loss
than at 1.04 kHz, so the level will be 6 dB below -2 dBm,
or -8 dBm.
EXAMPLE 3.
Assume that the output level of a circuit using parameter
S1 at 1.04 kHz is -3 dBm, and that the output level at 0.5
kHz is -2.5 dBm and the output level at 2.8 kHz is -5 dBm.
Does this circuit meet the requirements of parameter S1?
The difference between -3 dBm at 1.04 kHz and -2.5 dBm at
0.5 kHz is no more than 0.5 dB, well within the requirement
of no more than 1 dB less loss than at 1.04 kHz.
The
difference between -3 dBm at 1.04 kHz and -5 dBm at 2.8 kHz
is 2 dB, well within the tolerance of 3 dB more loss than
at 1.0 kHz.
1.
Practical Application of Selected Parameters.
Two additional
characteristics that are also closely monitored by the technical controllers
are maximum net loss variation and maximum allowable channel noise.
The
maximum net loss of a circuit is the total loss measured from the input of a
sending station to the output of the receiving station. Specifically, it is
the difference (loss) between the transmitted level and the receive level.
The maximum
39
Previous Page
