User manual

Table Of Contents
Publication No. 980935 Rev. M 3152B User Manual
Astronics Test Systems Introduction 1-17
Figure 1-10, Sequenced Waveforms
Modulated
Waveforms
The use of direct digital synthesis (DDS) technology makes the
3152B is agile. During operations such as sweep, FSK, FM, and
other modulation modes, the 3152B quickly synthesizes the
modulated waveform using
the DDS circuit. The variety of
modulated waveforms are described below.
Sweep
The 3152B can sweep the output frequency between minimum and
maximum values that you specify. You may sweep up or down
using linear or logarithmic increments. Sweep frequency is
programmable from 10 Hz to 100 MHz, and sweep times can range
from 1.4 µs to 40 seconds. Sweep mode is compatible with
Continuous, Triggered, and Gated modes.
Sweep modes with triangle and square waveforms
are computed
and placed in memory as complete waveforms. This adds
delay
before the initial output
is available while the software computes the
waveform. All sine swaps use the DDS circuit, thus
no computation
time is required.
FM
The FM function modulates the frequency of the 3152B output
waveform. You can modulate the output using built-in standard or
arbitrary
waveforms. FM is available in Continuous, Triggered, and
Gated modes.
The 3152B generates two types of frequency modulation: standard
and arbitrary. For standard modulation, the modulatio
n waveform is
selected from a built-in library of four
standard waveforms: sine,
triangle, square, and ramp. For arbitrar
y modulation, complex
modulation signals are loaded in
to modulation waveform memory.
There are 10,000 points allocated specifically for modulation
waveform memory.