HP 8753D - Page 463

T
able 7-12.
HP 8753D
Instrument Specications
(6
of
6)
INPUT
GENERAL (cont.)
Description
Specication
Code
GROUP
DELA
Y
CHARACTERISTICS
Group
delay
is
computed
by
measuring
the
phase
change
within
a
specied frequency
step (determined
by the
frequency
span
and
the
number
of
points
per
sweep).
Aperture
(selectable) (frequency
span)/(number of
points 0
1)
S-3
Maximum
Aperture
20%
of
frequency
span
S-3
Range
1/2
2
(1/minimum
aperture)
S-3
(The
maximum delay
is limited
to
measuring
no
more
than
180

of
phase
change
within
the
minimum
aperture
.)
A
ccuracy (see
graph) S-3
The
following
graph
shows
group
delay
accuracy with
an
HP
85047A T
est
Set
with
7
mm
full
2-port
calibration
and
a
10
Hz
IF
bandwidth.
Insertion
loss
is
assumed
to
be
<
2
dB
and
electrical
length
to
be
ten
meters
.
Group Delay A
ccuracy vs
. Aperture
In general, the following formula can be used to determine the accuracy
,
in seconds
, of specic group delay
measurement:
6 [0.003 2 Phase A
ccuracy (deg)]/Aperture (Hz)
Depending on the aperture and device length, the phase accuracy used is either incremental phase accuracy or
worst case phase accuracy
.
frequency span and the number of points
per sweep).
Aperture (selectable) (frequency span)/(number of points 0 1) S-3
Maximum Aperture 20% of frequency span S-3
Range 1/2 2 (1/minimum aperture) S-3
(The maximum delay is limited to measuring no more than 180

of phase change within the minimum aperture.)
Accuracy (see graph) S-3
7-32 Specications and Measurement Uncertainties