Lesson 3/Learning Event 3
(a) -Noise filter. The first two switches are used to select C-
MESSAGE WEIGHTING or 3 kHz FLAT when performing noise measurements on a
(b) The COUNT RATE, COUNT TIME and PUSH TO START switches are used
when performing three-level impulse noise hits and dropout measurements.
1. Count rate.
When the BELL STD switch is depressed, the
maximum total count is limited to seven hits per second, but when the CHNL
LTD is depressed, total count is only limited by the channel bandwidth and
selected noise filter within the test set.
2. Count time. When the 5 MIN or 15 MIN switches are depressed
the test set will count the noise hit/dropouts for 5 to 15 minutes
respectively before stopping, but if the NON STOP switch is depressed it
will count the hits/dropouts continuously until the reset switch is
(c) Push to start.
This switch must be depressed to start the
test or restart the test.