Solartron 1260 - Page 75

2.1.4
MODE
Selects
a
measurement
mode
suitable
for the results
to be
displayed
(see
Section
4).
«
[normal]
Single
measurement.
Used
for
all
displayed
functions,
except
r,t,
r(dB),h
and
auto
circuit.
•
[group
delay]
Triple
measurement.
Used
for
the
functions
r,t
and r(dB),
t, whose
prime
purpose
is
to
determine
the
transmission
quality
of
filters.
Time
t
represents
the delay
between
the
frequencies
F
-
n%
and
F+p%.
F,
the
generator
output
frequency,
and
the
values
n and
p
are all
defined
by the
user.
All
other
display
functions,
except
auto circuit,
may
be
derived
from
group
delay
measurements.
The
error
incurred
in
a group
delay
measurement
-
P^
se error
(tft
deg
rees
)
360 X
f
span
where
fspan
=F/n+p) Hz
f his
shows that
the
group
delay
error
is inversely
proportional
to
f
span
. To
minimize
the
group
delay
error
at the
lower
drive
frequencies,
increase
the values
of
n and
p
as
the
value
of F
is
decreased.
• [auto
impedance]
Double
measurement.
Used
primarily
for
the
auto
circuit
function,
but can
also
be
used for
any
other
function
except
r,t
and
r(dB),h
3)
b)
F
-
n%
0
meas.1
meas.2
d)
F
10
frequency
meas.!
meas.3
meas.2
A A
F
+ p%
frequency
meas.2
meas
.1
4
F x
10
frequency
frequency
F
=
Generator
FREQ
value
Fig
5.5
Measurement
modes:
a)
normal
,
b)
group
delay
,
c)
auto
impedance
(F
<128Hz),
d) auto
impedance
(F>
128Hz)
5.8
fWC/1 OCmn