Chapter 3 83
Making Measurements
AM Depth Measurement
Measurement Settings
To adjust measurement settings press Meas Setup.
IF BW
Allows the IF Bandwidth to be changed. Pressing this key automatically sets the
IF
BW Type
to Man.
Range is 1 kHz to 10 MHz.
IF BW Type
Selections are
Auto, Man, and Min.
Default setting is
Auto.
Auto performs an occupied bandwidth measurement on the modulated signal. This
measurement occurs at the start of any modulation measurement, and will
determine the final IF bandwidth used to analyze the signal. Measurement
throughput can be affected since extra time is required during measurement
initialization to perform the bandwidth measurement. Auto is usually sufficient for
most measurements.
Man (Manual) allows the experienced user to select a bandwidth for demodulation.
The value must be chosen with care since a value too low may result in inaccurate
results and a value too high will result in unwanted noise and increase the
measurement time. In Man mode, measurement throughput is increased over Auto
mode since the initialization occupied bandwidth measurement is not
automatically performed. When measurements of low rate or high deviation
FM/PM signals are necessary, select
Man type and manually set the IF BW using
the
IF BW key.
Min (Minimal) sets the IF BW to the minimal value necessary to perform the
modulation measurement. The minimum IF BW is determined by the Low Pass
filter setting and is a value that is >2* LP filter setting. This mode works for most
signals with a low modulation index. This mode also increases throughput over
Auto mode.
To change the average number between
On and Off, press the Avg Number key.
When setting to
On, enter the number. The default average setting is Off and the
default number is 25 when switching to
On. When the input signal is changed
during the average period, wait until the averaging is done or the next averaging
period starts.
To change the average mode, toggle the
Avg Mode key between Exp and Repeat.
The default average mode is
Repeat.
Trigger Source
Requires PSA firmware revision A.11.08 or above, or Option 23A.
Available trigger sources are
Free Run (immediate), Video (IF Envlp), RF Burst, Ext
Front
, or Ext Rear.
To Next Page
Loading...
Need help?
General
