Amber 5500 - Source Impedance

p
Amber model
5500
Owner’s Manual Version 07
Programmable
Audio Measurement
System
Section 2
2.2.
5
OUTPUT
SOURCE IMPEDANCE
(requires option
001
High
Level Balanced
Output)
Three
output
source
impedances
and
configurations
are
possible:
SOURCE
IMPEDANCE
CONFIGURATION
600
ohms
Balanced
150 ohms
Balanced
50
ohms Unbalanced
The three
possibilities
are selected
by
succes-
sive
pushes
of the CONFIGURATION button.
In the balanced modes the
output
should
be
taken from the
tip-ring-sleeve
jack,
in the
unbalanced mode the
signal
should be taken
from the BNC
jack.
The
signal
is available on
both
jacks
in both modes but
erroneous
levels
and/or
grounding problems may
occur
if the
wrong
jack
is used. The
panel
graphics
clearly
indicate the correct
jack
to use. Note
that when a
plug
is inserted into the BAL
jack,
the UNBAL
jack
is disconnected.
The
highest
drive level will be obtained
by
selecting
the
150
ohm balanced
configura-
tion.
This
mode
will
permit
a
+30
dBm
drive
into an external
600
ohm
load
(1 Watt).
The
600
ohm balanced mode should
be used
for
equipment
that
requires
a true
600
ohm
source
impedance.
The
50
ohm unbalanced
configuration
should
be used for unbalanced
equipment
such as
consumer
audio com—
ponents
that could be
damaged by
the
high
signal
levels
possible
in the
balanced
modes.
2.2.6 OUTPUT LOAD
IMPEDANCE
The
5500
stores two internal values
of exter-
nal load
impedance,
one for dBm
and
another for all other
units
(V, dBV).
These
stored values are
used to calculate the actual
generator output
drive level to
produce
the
correct level in
the external load. The
calcula-
tion
also
takes
into account the
specified
output
level and the
generator
source im-
pedance. Every
time
any
of these is
changed,
the
level
is
recalculated to
insure
the
correct
value
in the extemal load.
The load
impedance
default values
are as
follows:
dBm: 600 ohms
dBV and Watts
:
infinity
(open circuit)
2-19