Amber 5500 - Page 10

Programmable
Audio
Measurement
System
Section 2
2.1.8
Phase
Measurement
(Requires option
009)
The
instrument is able
to measure the
relative
phase
difference between
two
signals
of
the
same
frequency
with
the addition of
option
009. This mode
is selected as a SHIFT
of
NARROW
BAND LEVEL.
The
system
measures the
relative
phase
be-
tween
the
signal presented
to
INPUT
A
and
the
selected
input.
That
is,
if
input
B
is
selected
on the
INPUT SELECT
control,
the
phase
difference
between the
signals
at
A
and B
will be
measured.
Alternatively,
if IN-
TERNAL
OSC A is
selected,
the
phase
shift
between the
Generator A
Output
and
INPUT
A will be
measured. The
phase
measurement
facility
is the
only
one on the
instrument
to
use
two
signals
simultaneously.
Amber
model 5500
Owner’s
Manual
Version
07
Two
ranges
are
provided
to
allow
accurate
measurements
over a full
360°
range.
As is
typical
with
phase meters,
measurements of
two
signals
with
very
small
phase
differences
can
give ambiguous
results
(for
example,
near
0° or
360°).
Changing
to
a
different
range
inverts the
reference and
adds
180°
to
the
reading
to
avoid this
ambiguity.
The net
effect
of the double
inversion
(signal
polarity
reversal and
mathematical
addition of
180
to
the
measured
value)
ensures
that
the dis-
played
reading
is
always
correct.
The
phase ranges
are
selected
by Special
Function
8.
The
following
table
shows
the
recommended
operation
of this
phase
range
selection;
Table
2.1.8 Phase
Range
Selection
Total
Range
Recommended
Range
Selection
:
180°
-170°
to
+170°
8.0
SPCL
0 to
360°
10° to
350°
8.1 SPCL
Note that the
choice of
ranges
is
transparent
the
0
to
360°
range
(8.1
SPCL)
while a
value
to the
readout. For
example,
a
valueof
+60° of 2°
would be best
measured
on
the
:t
180°
could
be read
equally
on either
range.
How-
ever,
a value of
182° would be
best read on
range
(8.0
SPCL).
2-8
F.
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