Racal Instruments 3156B, Руководство пользователя

Страница: 22 / 385

3156B User Manual
Getting Started 1-2 Racal Instrument © 2005
Introduction
A detailed functional description is given following the general
description of the features, functions, and options available with the
Model 3156B.
The Model 3156B is a VXIbus, single slot, C-size, dual-channel
synthesized Waveform Generator, a high performance instrument that
provides six powerful functions in one small package. The 3156B
generates an array of standard waveforms from a built-in waveform
library as well as arbitrary, sequenced and modulated waveforms. The
3156B can also be used as a dual-channel 12-bit parallel pattern
generator up to 100Mbits/s and as video stroke generator. The
generator outputs 16-bit waveforms from two channels at up to
200MS/s with different waveform properties. The dynamic range is
greatly improved over 12-bit designs providing increased dynamic
range and lower “noise floor” making it ideal for the generation of
multi-tone signals and I&Q modulation.
Direct Digital Synthesis (DDS) technology, utilized in the design of the
3156B, allows flexibility in usage of features like FM, FSK, sweep and
frequency hopping. For example, the FM feature can be stimulated by
an internal source, or arbitrary FM waveform allowing the production
of customized chirp signals. Included WaveCAD software can be used
to breadboard custom frequency modulation profiles graphically.
Sample rates up to 200MS/s are available with memory size up to
1Meg. Channels A and B are both synchronized to the same sampling
clock however, each channel can output a different waveform shape
and length.
Based entirely on digital design, the 3156B has no analog functions
resident in its hardware circuits. Data has to be downloaded to the
instrument for it to start generating waveforms. The instrument can
compute and generate a number of standard functions such like sine,
square triangle and others however, complex waveforms must be
converted to an appropriate format and downloaded to the 3156B as
waveform coordinates. Dedicated waveform memory stores
waveforms in memory segments and allows playback of a selected
waveform when required. The waveforms are kept in the memory as
long as the power is on.
Frequency accuracy of the output waveform is determined by the
clock reference. Using CLK10 as the reference oscillator provides
100ppm accuracy and stability over time and temperature. If higher
accuracy and/or stability are required, one may select between two
options: Purchase the optional TCXO reference or, connect his own
reference oscillator to a front panel input and use this input as the
reference for the 3156B. Frequency may be is programmed with up to
10 digits, so using an external reference is recommended, if you
intend to utilize the full resolution provided by the instrument.