Operation
Model 8642A/B
Modulation Oscillator (cont'd)
Example
Set the Signal Generator to output a 2 Vpk, 10 kHz signal at the MOD OUTPUT
connector.
LOCAL
(keys)
(program
codes)
ENTRY
[
MOD
1
I
fREO
|
DATA
LUCE] CS
[
SHIFT
I
ENTRY
MOD OUT
I
MOD |
I
FREO
|
DATA
I
2 ) prH
MF
10 KZ ML 2 VL
Display
hi U JJ.L) U I C..KJ KJ K »_ (1 ILI.LJ JJ Nl
The modulation output level has been set to 2.00V.
Any function which is using the modulation oscillator as a source, (MOD OUTPUT or
internal AM, FM, $M, or pulse modulation), now has a rate of
1
0.00 kHz regardless of
any previous modulation oscillator rate setting. The cursor above the modulation output
value indicates Modulation Output is the active function.
HP-IB
Keys
MOD FREQ
MOD OUT level
kHz
Hz
V
mV
SPCL
Codes
MF
ML
KZ
HZ
VL
MV
SP
Comments Speeding Up Modulation Switching Time
At instrument turn on, all modulation oscillator frequency bands are characterized and
given a calibration factor (Modulation Frequency Calibration). When the modulation
oscillator frequency is set or the modulation oscillator placed in use, the selected
modulation oscillator frequency and its individual frequency band are recalibrated to
correct for inaccuracies due to changes in temperature (Modulation Frequency
Correction). A single calibration of all modulation oscillator frequency bands can be
initiated using Special Function 248.
If faster switching between modulation frequencies is desired, Modulation
Frequency Correction can be disabled by selecting Modulation Frequency Correction Off
(Special Function
1
13). This special function decreases switching time by approximately
200 ms. Automatic modulation frequency correction can be re-enabled by selecting
3-132
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