Aeroflex 2050T SERIES, Operating Manual, Page: 100 / 322

ANALOG MODULATION MODE
3-51
Selecting amplitude modulation
(1) At the Sig Gen menu, press [AM] , the [AM Depth] box is now highlighted.
(2) Enter the required modulation depth via the numerical key pad and terminate with the [%]
key. If the modulation depth requested exceeds 99.9%, the depth is reset to the maximum
value available and the message:
ERROR 56: AM Outside Limits
is displayed at the top of the screen.
(3) Switch the AM ON or OFF by pressing [AM ON/OFF] . The AM information is displayed in
the lower half of the screen.
Selecting frequency modulation
(1) At the Sig Gen menu, press [FM] , the [FM Devn.] box will be highlighted.
(2) Enter the FM deviation value via the numerical key pad and terminate it with [Hz], [kHz] or
[MHz].
(3) Switch the FM ON or OFF via [FM ON/OFF] . The FM information is displayed in the lower
half of the screen.
Selecting phase modulation
(1) At the Sig Gen menu, press [
Φ
M] . The [
Φ
M Devn . ] box will be highlighted.
(2) Enter the phase modulation deviation value via the numeric key pad and terminate it with the
[rad] key.
(3) Switch the
Φ
M ON or OFF via the [
Φ
M ON/OFF] key. The
Φ
M information is displayed in
the lower half of the screen.
Selecting wideband frequency modulation
(1) At the Sig Gen menu, press [Wideband FM] . The [Wideband FM] box will be highlighted.
(2) The value can be changed via the key pad and frequency terminator key. To preserve the
widest bandwidth, the control of the wideband FM is carried out in a series of fixed steps and
the signal generator automatically displays the calculated fixed step which is closest to the
keyed in value. Applying a 1 V RMS sine wave to the rear panel WIDE BAND FM IN socket
will produce the indicated deviation.
(3) Pressing [AC/DC Coupling] changes the coupling from AC to DC and vice versa. When the
input is DC coupled, small frequency offsets can be reduced by using the nulling facility.
Nulling can be effected by pressing
[DCFM Nulling]. The legend:
*** DCFM NULLING ***
appears briefly on the display.
The [
×
] and [
Ø
] keys and the control knob do not operate for wideband FM.
The WBFM socket input impedance is 50
Ω
. The DC component of of any applied voltage must
not exceed 5 V.
Modulation source frequency
(1) At the Sig Gen menu press [Source Freq.] .
(2) Enter the required source frequency and terminate the entry with [Hz], [kHz] or [MHz].
When the modulation source is operating as a continuous signalling tone the [Source Freq.]
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