R&S SMJ100A, Operating Manual

Page: 267 / 874

Instrument Function
R&S
®
SMJ100A
251 Operating Manual 1403.7458.32 ─ 14
ɸ
M Sensitivity
Displays the input sensitivity of the externally applied modulation signal at the EXT
MOD input in RAD/V.
The modulation deviation entered with
ɸ
M Deviation "
ɸ
M Deviation" is achieved with 1
Volt (=U
peak
) of the input signal.
Note: The input voltage should not exceed 1.1 V
p
otherwise modulation distortions
might occur.
Remote command:
[:SOURce<hw>]:PM:SENSitivity?
on page 761
Mod External Coupling
Selects the coupling mode ("AC" or "DC") for the external modulatioin signal.
Note: Coupling for external feed via input EXT MOD can be set independently for all
modulations using the external modulation signal.
"AC" Disconnects the DC voltage component and uses only the AC com-
ponent of the modulation signal.
"DC" Uses the modulation signal with both components, AC and DC.
Remote command:
[:SOURce<hw>]:PM:EXTernal:COUPling
on page 760
External Input Impedance
(Source External only)
Sets the impedance for the external modulation signal, applied at the EXT MOD con-
nector.
You can select 50 Ohm or high (>100 kOhm).
Note: The selection of 50 Ohm to ground requires that your instrument is equipped
with the extended synthesis assembly (SynEx).
This setting affects all analog modulations which use the external modulation signal.
Remote command:
[:SOURce<hw>]:INPut:MODext:IMPedance
on page 721
5.5.11.6 Pulse Modulation (PM)
Pulse modulation is available for the basic unit (R&S SMJ + frequency option
R&S SMJ-B10x) without additional equipment options.
An internal or external source can be selected for pulse modulation. A simple rectangu-
lar signal with selectable repetition frequency is available as the internal signal. This
signal is formed from the sinusoidal signal supplied by the LF generator.
The external signal is input via the EXT MOD connector at the rear of the instrument.
The polarity of the external pulse modulation can be selected. If Polarity is set to Nor-
mal, the RF level is ON if the level is HIGH at the modulation input.
RF Signal and Analog Modulations - RF Block