Keysight E8663D, Руководство пользователя

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176 Keysight E8357D/67D & E8663D PSG User’s Guide
Analog Modulation
Configuring FM (Option UNT)
Configuring FM (Option UNT)
In this example, you will learn how to create a frequency–modulated RF carrier.
For a E8267D with Option 018, see also “Wideband IQ/FM Mode <3.2 GHz
(Option 018)” on page 171 .
To Set the RF Output Frequency
1. Press Preset .
2. Press Frequency > 1 > GHz .
To Set the RF Output Amplitude
Press Amplitude > 0 > dBm.
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.