Related Special Functions; Modulation Frequency Correction Off; Calibrate The Modulation Frequency Bands Again - HP 8642A Operation And Calibration Manual

Operation
Model 8642A/B
Modulation, Pulse (cont'd)
Related
Special
Functions
Related
Operating
Instructions
3-130
Mixed Modulation
The Signal Generator can simultaneously modulate the RF signal with more than one
modulation type. The Signal Generator does not allow simultaneous AM and pulse
modulation or FM and <PM. Pulse modulation is allowed
In
the following
combinations:
Either
$
Internal pulse modulation or
e Ext.ernal dc-coupled pulse modulation
With anyone of the following:
@
Internal FM,
o External ac- or dc-coupled FM,
8
Internal + external ac- or dc-coupled FM,
~ External low rate FM (Special Function 5),
$
Internal
+
external low rate FM (Special Function 112),
• Internal <PM,
o
External ac- or dc -coupled \PM, or
o
Internal + external ac- or dc-coupled \PM.
NOTE
All internal modulation sources use the internal modulation
oscillator, therefore all internal modulation, as well as MOD
OUTPUT, will have the same modulation frequency.
113. Modulation Frequency Correction Off. This special function disables the
single- band calibration of the modulation frequency oscillator that normally occurs
whenever the modulation oscillator frequency is set or the internal modulation
oscillator is put into use. When this calibration is disabled, the typical modulation
frequency switching time is decreased by approximately 200 ms. For more
information, refer to "Speeding Up Modulation Switching Time" on page 3-132.
213. Modulation Frequency Correction On. This special function re-enables the
modulation frequency correction disabled with Special Function 113.
248. Calibrate the Modulation Frequency Bands Again. This special function enables
you to initiate the calibration sequence that normally only occurs during instrument
power-up. This function can be used, for example, to recalibra te the modulation
oscillator frequency bands if normal modulation frequency correction has been
disabled with Special Function 113. Calibration typically takes one to two seconds.
Refer to Modulation Oscillator (page 3-131) for more information on the internal
modulation oscillator that is the common source for all internal modulation as well as
for the MOD OUTPUT connector.
Refer to Operating Messages (page 3-177) if the instrument displays a message you
wa nt clarif ied.
Refer to Special Functions (page 3-165) for information about the way these are
accessed.