Sweep Operation; General - Metrix GX1010 Notice De Fonctionnement

When Noise is selected, see Special Waveforms section, this 7-stage filter is always off,
whatever the FILTER = setting, and a simple 700kHz low pass RC filter is switched in
instead.
4.2.3.3. Auxiliary Output
When sine, triangle, squarewave or pulse waveforms are selected and with AUX
OUTPUT=AUTO the auxiliary output squarewave generation switches automatically at
30kHz from DDS generation to a signal derived from a comparator driven by the DDS
sinewave; the advantages of this approach are the same as those detailed previously in the
Squarewave Generation section. However, as detailed in the Auxiliary Output Phase
section, the high frequency generation mode has the disadvantage that a phase difference
can no longer be set between AUX OUT and MAIN OUT. The automatic switchover at
30kHz can therefore be overridden by setting AUX OUTPUT=LOW FREQuency, to
maintain it in true DDS mode, or AUX OUTPUT=HIGH FREQuency to lock it in high
frequency mode. With AUX OUTPUT=AUTO there is no automatic mode changeover if
ramp, staircase or arbitrary waveforms are selected; high frequency mode can however be
forced by setting AUX OUTPUT=HIGH FREQ.
Note that there is some second order interaction between the Squarewave Generation,
Filter and Auxiliary Output settings which demand a little thought before deviations from the
default conditions are defined. For example, if SQWAVE GEN and AUX OUTPUT options
are set to AUTO but FILTER is set to OFF the edges of both the MAIN OUT and AUX OUT
squarewaves will exhibit some jitter at high frequencies (e.g. 1MHz) because the sinewave
driving the comparator from which both are derived will itself be jittery.
4.2.3.4. Frequency Stop
In the default mode of FSTOP=OFF there are no frequency limits on any waveform and the
frequency and waveform can be set as described in the Main Generator section; waveform
quality will however deteriorate progressively as the frequency increases for certain
waveforms, as discussed in the DDS Principles section. With FSTOP=ON the maximum
settable frequency for triangle, ramp, staircase and arbitrary is limited to 100kHz. Error
messages will be shown if either an attempt is made to enter a frequency above 100kHz
whilst one of these waveforms is selected, or if an attempt is made to select one of these
waveforms with the frequency already set above 100kHz. This mode is useful in ensuring
that frequencies are not accidentally set too high for waveforms whose quality will
deteriorate above 100kHz.
4.2.3.5. Trigger/Sweep Output
With SWEEP/TGEN=AUTO the function of the rear panel TRIG/SWEEP OUT socket
changes automatically when the operating mode is changed between Sweep, HOP and
any other mode; the two functions of this output are described in the Connections section.
When SWEEP/TGEN=SWEEP is set the TRIG/SWEEP OUTput is always in the Sweep
mode, if sweep is operational, or HOP mode if HOP is on; when SWEEP/TGEN=TRIG the
TRIG/SWEEP OUTput always outputs the internal trigger generator signal. Note that,
except when using the internal trigger generator in Trigger, Gate, FSK or AM modes, this
signal is not synchronised with the main generator.
4.3.

Sweep Operation

4.3.1. General

DDS operation gives the significant advantage over conventional function generators of
phase-continuous sweeps over very wide frequency ranges, up to 10
be remembered that the frequency is actually stepped, not truly linearly swept, and thought
needs to be given as to what the instrument is actually doing when using extreme
GX1010
10
:1. However, it must
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