114 Chapter 15 - Spectrum analyzer
10713 Vxx.11
15.10.4
Application
There are two basic applications.
„Line up“ a system:
A profile is created with the channels that are occupied in the system. Move the 1
st
cursor onto the
lowermost channel and the 2
nd
cursor onto the uppermost channel. First set the lowermost channel
to the desired absolute level. You then have two options.
No predistortion:
Set the level of the uppermost channel so that the reference line between the two cursors is
horizontal or raise the level display.
With predistortion:
Set the level of the uppermost channel appropriately higher.
The channels in between can then be “lined up” using the reference line.
Checking the tilt of the system:
A profile is created with the channels which are to be analyzed in the test. This may be fewer than
the number which are occupied in the system. Including fewer channels increases the repetition
rate.
Move the two cursors to the uppermost and the lowermost channels. Then check the level lines of
the channels in between using the reference line.
15.11
Switching to measuring receiver mode
In most modes you can switch directly from the analyzer to measuring receiver mode while in all
measuring ranges. The instrument uses the current cursor frequency to tune the measuring
receiver. In the ranges FM and RK direct switching is only possible in the lower spans, not
FULLSPAN. At TV is possible in channel mode only, but in every span. Press
ENTER
to trigger the
process.
As already mentioned in the "Chapter 15.4 - Cursor", in range TV the instrument can distinguish
between analog and digital channels based on the spectrum. This feature is used when switching
into the measuring receiver mode. When the instrument detects an ATV channel, the
corresponding measuring receiver mode is activated.
If it is a digital channel, the instrument switches to the last digital mode that was active (DVB-C,
DVB-T or DOCSIS).
