HP 70340A, Руководство пользователя

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ALC INT
Selecting the
NNNNNNNNNNNNNNNNN
Amptd men u and then the
NNNNNNNNNNNNNNNNNNNNNNN
ALC INT (ALC INTERNAL) softkey pro vides a
lev eled output signal at the RF OUTPUT connector that is held constan t o v er the en tire
frequency range of the instrumen t.
When the ALC INTERNAL function is active, it is indicated b y an underscore; the display
reads \ ALC INTERNAL ."
Under 4
INSTR PRESET
5 ( 4
I-P
5) conditions, ALC INTERNAL is enabled.
In ternal ALC is used to con trol the in ternal RF signal o v er a sp ecied range (the v ernier
range) of 04 to +10 dBm. Additional dynamic range is pro vided b y an optional 90 dB step
attenuator (Option 1E1) to give an eective dynamic range of 090 to +8 dBm.
An ALC Unlev eled condition o ccurs when the in ternal ALC circuitry cannot maintain
lev eling. This may happ en b ecause of an instrumen t fault or b ecause the instrumen t is set
to lev el for an RF output lev el that is b ey ond its capabilit y . Calibrated output lev el is only
guaranteed when the UNLEVELED Led is not lit.
Whe the signal generator UNLEVELED Led lights, the Knob arrow k eys or the n umeric
k eypad can still b e used to c hange display ed p o w er up to the maximum v alue. Ho w ev er, the
actual output p o w er will not increase. Only the display ed v alue c hanges.
The in ternal ALC circuit maintains a constan t RF p o w er lev el o v er frequency at the RF
OUTPUT connector. The ALC circuit is a feedbac k con trol system where output p o w er is
measured and compared to the desired p o w er lev el. When output p o w er do es not equal the
desired p o w er lev el, the ALC c hanges the output un til the actual and desired lev els are equal.
The allo w able range for p o w er lev el en tries (using the AMPLITUDE function under the
Amplitude men u) is 015 dBm to +30 dBm for standard conguration instrumen ts and 0100
dBm to +30 dBm if option 1E1 is installed.
The actual maximum lev eled p o w er a v ailable is dep enden t up on the frequency and v aries
across the range of the signal generator.
Note
The actual maximum in ternally lev eled output p o w er for y our instrumen t at a
given frequency can b e found b y increasing the signal generator output p o w er
un til the UNLEVELED Led lights.
Adv antages of Internal Lev eling
In ternal lev eling is self-con tained; it do es not require an y external equipmen t as do es external
dio de lev eling or external p o w er meter lev eling. Lev eled p o w er is sp ecied at the RF
OUTPUT connector.
Signal Generator Menus and Functions 5-9
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