Aim TTi TGR2050 Manuel D'instructions page 11

Note that when an increment would have taken the level above the instrument's maximum output
the setting becomes +7dBm (or 500mV). The next decrement returns the level to the last in-
range setting and further decrements reduce the level by the specified step size. Similarly when a
decrement would have taken the level below the instrument's minimum the setting becomes
–127dBm (or 0.1µV) and the next increment returns the setting to the last in-range setting, etc.
Modulation
The generator can be set for internal or external AM, FM or Phase Modulation (PM). With the ►
selection cursor in the MODulation field of the main menu, successive presses of the TYPE key
will step the generator through all available combinations of internal and external AM, FM and
PM; alternatively the selection can be made by using the rotary control or ▲▼ keys.
Amplitude Modulation (AM)
The choices are INTernal at 400Hz, INTernal at 1kHz or EXTernal; with EXTernal selected the
specified modulation frequency range can be applied to the MODULATION IN/OUT socket.
With AM selected the DEPTH/DEVIATION field automatically displays DEPTH. With the ►
selection cursor in the depth field the modulation depth can be set directly from the keyboard in
%, or changed using the rotary control or ▲▼ keys; modulation depth can be set from 0.5% to
100% in 0.5% increments.
With EXTernal modulation selected, the specified modulation depth is achieved with a 1Vrms
sinewave modulation signal.
With AM selected the maximum RF output level is +1.0dBm. If a higher output level has been set
(with AM and/or RF OUT off) then a warning message "+1dBm MAX WITH AM ON" will show
temporarily and the RF OUT level will be reduced to +1dBm. The output level setting will remain
at +1dBm when AM and/or RF OUT are turned off.
Frequency Modulation (FM)
The choices are INTernal at 400Hz, INTernal at 1kHz or EXTernal; with EXTernal selected the
specified modulation frequency range can be applied to the MODULATION IN/OUT socket.
With FM selected the DEPTH/DEVIATION field automatically displays Peak DEViation. With the
► selection cursor in the PK. DEV field the peak deviation can be set directly from the keyboard,
in kHz, MHz or GHz, or changed using the rotary control or ▲▼ keys; peak deviation can be set
to a resolution of 0.5kHz.
With EXTernal modulation selected, the specified peak deviation is achieved with a 1Vrms
sinewave modulation signal.
The maximum peak deviation achievable depends on the carrier frequency, see Specification
section. If a peak deviation is entered (with MOD ON) which is greater than the maximum for the
set carrier frequency then a warning message "PK. DEV LIMITED BY CARRIER FREQUENCY"
will show temporarily and the peak deviation will be changed to the maximum permitted for the
set carrier frequency. The peak deviation frequency in the display is marked with a ∗ to show
that it differs from that entered; the entered value will be restored when FM and/or MOD ON/OFF
are turned off.
The default FM settings are internal 1kHz modulation, 50kHz peak deviation, modulation off; FM
is also the instrument's default modulation setting.
Phase Modulation (PM)
The choices are INTernal at 400Hz, INTernal at 1kHz or EXTernal; with EXTernal selected the
specified modulation frequency range can be applied to the MODULATION IN/OUT socket.
With PM selected the DEPTH/DEVIATION field automatically displays Peak DEViation. With the
► selection cursor in the PK. DEV field the peak deviation can be set directly from the keyboard,
in rads, or changed using the rotary control or ▲▼ keys; peak deviation can be set to a
resolution of 0.05 rads up to 10.0 rads and to a resolution of 0.1 rads above 10.0 rads.
10