Ectron 441A, Инструкция по эксплуатации, Страница: 38 / 74

FILTERING
There are three types of selectable filters in the Model 441A: input, output, and periodic-error.
The first two are analog low-pass filters, and the last is a digital filter. These filters have
the following characteristics and application.
Input Bandwidth Filter
This filter is used to reduce noise on the input frequency
signal to provide reliable triggering. The screens are
labeled
MIN
,
MID
, and
MAX
bandwidth corresponding
to a single-pole low-pass filter with approximate corner
frequencies of 10 Hz (
MIN
), 500 Hz (
MID
), and
150 kHz (
MAX
). The proper setting for this filter de-
pends on the noise frequencies and their relation to the
desired signal and is usually set by trial and error in
conjunction with the sensitivity control
INPUT SEN-
S
itivity. Use the lowest bandwidth setting that provides
reliable triggering. Frequently, best operation is obtained
with the filter frequency set below that of the signal of
Figure 4-5
Maximum Output Noise with a 1 V Sine-wave Input
Applications Model 441A
4-8