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Chapter 5 141
Analog Modulation
Configuring the LF Output (Option UNT)
Configuring the LF Output (Option UNT)
With Option UNT, the signal generator has a low frequency (LF) output (described on page 10). The
LF output’s source can be switched between Internal 1 Monitor, Internal 2 Monitor, Function Generator 1, or Function
Generator 2
.
Using
Internal 1 Monitor or Internal 2 Monitor as the LF output source, the LF output provides a replica of
the signal from the internal source that is being used to modulate the RF output. The specific
modulation parameters for this signal are configured through the AM, FM, or FM menus.
Using
Function Generator 1 or Function Generator 2 as the LF output source, the function generator section of
the internal modulation source drives the LF output directly. Frequency and waveform are configured
from the LF output menu, not through the AM, FM, or FM menus. You can select the waveform shape
from the following choices:
Sine sine wave with adjustable amplitude and frequency
Dual-Sine dual-sine waves with individually adjustable frequencies and a percent-of-
peak-amplitude setting for the second tone (available from function generator 1
only)
Swept-Sine a swept-sine wave with adjustable start and stop frequencies, sweep rate, and
sweep trigger settings (available from function generator 1 only)
Triangle triangle wave with adjustable amplitude and frequency
Ramp ramp with adjustable amplitude and frequency
Square square wave with adjustable amplitude and frequency
Noise noise with adjustable amplitude generated as a peak-to-peak value (RMS value is
approximately 80% of the displayed value)
DC direct current with adjustable amplitude
NOTE The LF Out Off On softkey controls the operating state of the LF output. However, when the LF
output source selection is Internal Monitor, you have three ways of controlling the output. You
can use the modulation source (AM, FM, or FM) on/off key, the LF output on/off key, or the
Mod On/Off softkey.
The RF On/Off hardkey does not apply to the LF OUTPUT connector.
To Configure the LF Output with an Internal Modulation Source
In this example, the internal FM modulation is the LF output source.
NOTE Internal modulation (Internal Monitor) is the default LF output source.
Configuring the Internal Modulation as the LF Output Source
1. Press Preset.
2. Press the
FM/ΦM hardkey.
3. Press
FM Dev > 75 > kHz.
4. Press
FM Rate > 10 > kHz.