Model 8903B Service
is the lowest frequency and 255 is the highest.
For
N=O through 255, the Notch Filter coarse-tune code
is
set
to
the number specified by
N.
(N is keyed in as a decimal value and not a hexadecimal value.) Fine tuning of the
Notch Filter
is
via the automatic tuning circuitry on the Notch Filter Assembly. See Service Sheet 3 and Special
Function 53.N.
55.N
Oscillator Frequency Range.
Permits the frequency range
of
the Oscillator
to
be displayed or manually set.
If no suffix is keyed in (that is, 55. SPCL), the current Oscillator range is displayed, where
0
is
the lowest range
and
3
is the highest. For N=O through 3, the Oscillator
is
set
to
the range specified by
N.
See Service Sheet 8
and Special Functions 56.N and 57.N.
56.N
Oscillator Coarse Tune.
Permits the coarse-tune code of the Oscillator
to
be displayed or manually set. If
no suffix
is
keyed in (that is, 56. SPCL), the current Oscillator coarse-tune code is displayed, where
0
is
the lowest
frequency and 255 is the highest. For N=O through 255, the Oscillator coarse-tune code
is
set
to
the number
specified by N.
(N
is keyed in
as
a decimal value and not a hexadecimal value.) See Service Sheet 9 and Special
Functions 55.N and 57.N.
57.N
Oscillator Fine Tune.
Same
as
Special Function 56.N except that it pertains
to
fine tuning.
58.N
Source Fine Level.
Permits the fine-level code
of
the Source to be displayed
or
manually set.
If
no suffix is
keyed in (that
is,
58.
SPCL), the current Source fine-level code is displayed, where
0
is
the lowest level and the
255 is the highest. For N=O through
255,
the Source fine-level code
is
set
to
the number specified by N.
(N
is
keyed in as a decimal value and not a hexadecimal value.)
See
Service Sheet
10
and
Special Function 59.N.
59.N
Source Coarse Level.
Permits the coarse-level code
of
the Source
to
be displayed or manually set.
If
no
suffix is keyed in (that is, 59. SPCL), the current Source coarse-level code is displayed where 31
is
the lowest level,
0
is the highest, and 32 through 63 switch the level
off.
For
N=O
through 63, the Source coarse-level code
is
set
to
the number specified by
N.
For
N=O through 31, the level
is
controlled in
2.5
dB
steps, where the attenuation is
N
times
2.5
dB.
(N
is
keyed in
as
a decimal value and not a hexadecimal value.) See Service Sheet
11
and Special
Function 58.N.
60.0
Key Scan.
The keyboard
is
scanned and a keycode is displayed and output
to
the HP-IB. The key codes are
shown in Figure 8-6.
NO KEY
PRESSED:
99
.
..
El
n
0
0
I1
Figure 8-6. Key Codes
for
Key Scan (Service Special finction 60.0)
To
use the Key Scan Special Function, remove the instrument top cover. Key
in
60.0 SPCL, then jumper A8U6
pin 7 to A8TP3 (GND) on the
A8
Controller/Counter Assembly. Press the front-panel keys and observe the right
display. If
two
or
more keys are pressed simultaneously, the display shows the
first
one found in its normal scan.
See Service Sheet 17.
Two
simple programs for displaying the
key
codes on a computing controller are shown in Table 8-3. Removal
of
the
top
cover is unnecessary. The Audio Analyzer is assumed
to
have HP-IB address 28.
rev.
20
JUN8
7
8-13
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