Agilent E8663B Analog Signal Generator User’s Guide
61
Analog Modulation
Configuring
Φ
M
To Set the FM Deviation and Rate
1.
Press the
FM/
Φ
M
hardkey.
2.
Press
FM Dev
>
75
>
kHz
.
3.
Press
FM Rate
>
10
>
kHz
.
The signal generator is now configured to output a 0 dBm, frequency- modulated carrier at 1 GHz
with a 75 kHz deviation and a 10 kHz rate. The shape of the waveform is a sine wave. (Notice that
sine is the default for the
FM Waveform
softkey. Press
More (1 of 2)
to see the softkey.)
To Activate FM
1.
Press
FM Off On
to On.
2.
Press
RF On/Off
.
The
FM
and
RF ON
annunciators are now displayed. This indicates that you have enabled frequency
modulation and the signal is now being transmitted from the RF OUTPUT connector.
DC Offset and External FM
Applying a DC offset to an external FM signal will shift the frequency of the FM signal above or
below the carrier frequency, depending on the polarity of the DC level. The amount frequency shift is
directly related to the amplitude of the DC level. A DC offset of +1.0 volt or greater will shift the
external FM frequency by an amount equal to the maximum deviation setting. For example, if the
signal generator CW frequency is 1 GHz and the maximum deviation setting is set to 100 kHz, an
external DC- coupled signal with a +1.0 volt DC level used as the modulating source will center the
FM signal at 1 GHz + 100 kHz. Keeping the same setup and settings and changing the DC level to
+0.5 volts will center the FM signal at 1 GHz + 50 kHz.
Configuring
Φ
M
In this example, you will learn how to create a phase- modulated RF carrier.
To Set the RF Output Frequency
1.
Press
Preset
.
2.
Press
Frequency
>
3
>
GHz
.
To Set the RF Output Amplitude
Press
Amplitude
>
0
>
dBm
.
To Set the
Φ
M Deviation and Rate
1.
Press the
FM/
Φ
M
hardkey.
2.
Press the
FM
Φ
M
softkey.
3.
Press
Φ
M Dev
>
.25
>
pi rad
.
4.
Press
Φ
M Rate
>
10
>
kHz
.