Agilent Technologies HP 83711A, User Manual

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INT LEVEL
The 4
INT LEVEL
5 key enables internal leveling. Internal leveling uses an
internal ALC (automatic level control) detector to provide automatic level
control of the output power at the RF OUTPUT connector .
When the 4
INT LEVEL
5 key is pressed, the INT (ALC) annunciator will be lit.
Internal leveling is used to control the internal RF signal over a specied
range (the vernier range) of 01 to +13 dBm. A dditional dynamic range
is provided by an optional 0110 dB step attenuator (Option 1E1) to give
an eective dynamic range of 0110 to +8 dBm (090 to +8 dBm on HP
83711A/12A).
An ALC unleveled condition occurs when the internal ALC circuitry cannot
maintain leveling. This can occur due to an instrument fault or because the
instrument is set to level for an RF output level that is beyond its capability .
Calibrated output level is only guaranteed when the UNL VL annunciator is
not lit.
When the synthesizer UNL VL annunciator lights , the knob , arrow keys , or
the numeric keypad can still be used to change displayed power up to the
maximum value . However , the actual output power will not increase . Only
the displayed value changes .
The internal ALC circuit maintains a constant RF power level over frequency
at the RF OUTPUT connector . The ALC circuit is a feedback control system
where output power is measured and compared to the desired power level.
When output power does not equal the desired power level, the ALC changes
the output until the actual and desired levels are equal.
The actual maximum leveled power available is dependent upon the
frequency and varies across the range of the synthesizer .
The allowable range for power level entries (using the 4 POWER LEVEL 5 key) is
015 dBm to +30 dBm for standard conguration instruments and 0120 dBm
(0100 dBm on HP 83711A/12A) to +30 dBm if Option 1E1 is installed.
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