Checking
the
crosstalk
Measure
at
the
MPX
output
with
an
oscilloscope
with
high
overload
capability
(for
L/R
crosstalk
checks)
and
with
a
selective
AF
voltmeter
(for
M/S)
according
to
sections
5.3.7
and
5.3.8.
Checking
the
distortion
Apply
a
signal
to
the
L
or
R
input
with
a
level
of
+6
dEm
or
+12.5
dBm
at
frequencies
of
30
Hz,
500
Hz
and
5
kHz.
Measure
the
harmonics
at
the
corres-
ponding
output
of
the
decoder.
Checking
the
intermodulation
distortion
to
DIN
4540}
Apply
a
signal
to
the
L
or
R
input'via
two
identical
decoupling
resistors
of
about
18
k9
using
two
generators.
Frequencies
fl
=
13
kHz
and
f2
=
14
kHz.
Adjust
the
same
level
on
both
generators
to
that
the
meter
J1
indicates
"+6
dEm”
or
"+l2.5
dEm".
Measure
the
amplitudes
at
the
corresponding
decoder
outputs:
fl:
V1
(13
kHz)
f2:
V2
{14 kHz)
2fl
-
f2:
81
(12
kHz)
2f2
-
f1:
SE
(15 kHz)
f2
-
fl:
D
(1 kHz)
If
the
distortion
is
<
10%,
the
intermodulation
distortion
components
may
be
calculated
in
accordance
with
DIN
45403
as
follows:
D
_
51
+
32
2
‘
V1
+
V2
d
d
3
_
Vl
+
V2
Checkigg
the
carrier
suggression
Apply
a
signal
to
both
inputs:
L
=
R
=
+6
dEm
at
500
Hz.
Measure
at
the
MPXl
output
(Eu40)
at
38
kHz.
Checking
the
weighted
and
unweighted
noise
voltages
Measure
at
the
decoder
output
with
the
psophometer,
the
L
and
R
inputs
of
the
GC
00}
being
short-circuited
and
with
the
preemphasis
in
the
coder
and
deemphasis
in
the
decoder
switched
on.
R
38122
—
16
