Orban 418A - Appendix B: Specifications; Input; Output; Frequency Response

(12)
Operate
the distortion analyzer
so that
the
scope
displays
the input to
the distortion
analyzer.
Reduce
analyzer
sensitivity until
no overload
occurs.
With
scope
in NORMAL
TRIGGER
mode,
adjust TRIGGER
LEVEL
until
sweep barely
shuts
off.
(13)
As
you did
with the broadband
limiter
test in
step
8,
alternately
connect and
remove the
hot lead
from
the
oscillator,
while
observing
the
scope as it
triggers
on the overshoot
from
the
high-frequency
limiter.
Adjust
P209 (high-frequency
FET
bias) until
the
scope
displays a
single-shot
pattern
like
FIG.
3
with the
scope time base
adjusted
for
1 ms/cm.
HIGH FREQUENCY
LIMITER ATTACK
(5
kHz
—
no signal to 10
dB gain reduction)
(5V/cm; 1
mS/cm)
FIGURE
3
(14)
Connect the
distortion analyzer
to
fork
terminal
^5
(and readjust
the oscilloscope
triggering
so that the
distortion
signal can
be
viewed).
Measure the har-
monic distortion.
Reduce the
level
of
the
oscillator
until the distortion
is maximum.
Adjust P208
(right
h. f. distortion
null)
to
minimize THD.
(15)
Connect the oscillator
to
the LEFT
AUDIO
INPUT
and
repeat step
14,
connecting the distortion
ana-
lyzer to
the
left
channel h. f.
limiter output
(termi-
nal
2),
and
adjusting
P207 (left h. f.
distortion
null)
for
minimum distortion.
This
concludes the alignment
procedure.
APPENDIX
B:
SPECIFICATIONS
INPUT:
Impedance:
150 k ohms
balanced;
active differential
input.
Level: -10
dBm
produces 10
dB
gain reduction with
jnpjut attenuator
fully
clockwise.
Absolute
input overload
occurs at
+ 21 dBm.
OUTPUT:
Impedance:
less than
400
ohms,
unbalanced.
Level:
+ 4
dBm nominal
with
output
attenuator
full
clockwise.
Peak
level
approximately
+ 12 dBm.
y
FREQUENCY
RESPONSE:
±
0.5 dB,
20-20,000
Hz
below
high-frequency
limiter threshold.
HIGH-FREQUENCY
LIMITER:
Controls
high-frequency
peaks attempting
to
exceed a threshold
defined
by a single-time-
constant
rolloff
of
75,
50, 37.5, or 25 microseconds,
±3%. Rolloffs
are switch
selectable
from
front panel,
and
high-frequency
limiter
is defeated in
“flat” position.
Attack Time:
approximately
3 milliseconds.
Release Time: varies
around
15
milliseconds
according to
program
history.
Control Element:
junction
field-effect
transistor
BROADBAND
LIMITER:
Attack Time:
1 to
2 milliseconds.
Release
Time:
Program-controlled
by means
of quadruple
time-constant
release time
analog
processor.
Release
time
may be
scaled fast or
slow
by means of
continuously
variable
Release
Time
control available
to
user.
Range
of Gain
Reduction:
greater than
15 dB.
Compression Ratio:
in excess
of 200:1
Interchannel Tracking:
±
1.5 dB
max.; 1
1 dB typ.
Control
Element:
junction
field-effect
transistor
SEPARATION:
50 dB or better,
20-20,000
Hz.
NOISE (dB below
limiting
threshold
at 100
Hz; 20-20,000
Hz bandwidth):
-80
dB typ.; -75
dB max.
TOTAL
HARMONIC
DISTORTION:
(See
graph)
Ibtai
Harmonic
Dmortion
(<M>)
OPERATING
CONTROLS:
OUTPUT
ATTENUATOR
(left and
right
ganged)
INPUT
ATTENUATOR
(left and
right
ganged)
RELEASE
TIME
H-F
LIMITER
TIME
CONSTANT
75
uS;
50 uS; 37.5
uS; 25
uS; flat
METER
SELECTOR
left input;
right
input; left
output;
right
output;
gain reduction;
-f
15
volt
power
supply;
-15 volt
power
supply
AC
UNE OFF/ON
INDICATORS:
AC POWER
PILOT
LAMP
OVERLOAD
(tights if attempt
is made
to
exceed possible
broadband
AGC
range)
METER [3.5”
(8.9 cm) with VU
“A” scale and
characteristics]
POWER
REQUIREMENT:
115/230
VAC
±
10
%;
50-60
Hz,
approximately
6 watts.
U-ground
power
cord
attached.
DIMENSIONS:
19"
(48.3 cm)
wide x
3.5"
(8.9 cm) high
x
10”
(25.4
cm) deep.
OPERATING
TEMPERATURE
RANGE:
0-50°
C.
WARRANTY:
1
year, parts and
labor.
Subject to
limitations
set
forth in
our standard
warranty
agreement.
9