Omicron CMC 356, Справочное руководство

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CMC 356 Reference Manual
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4.2 Signal Generation
The generation of sine wave signals with high amplitude and phase
accuracy is required in order to achieve output signals with the specified
accuracy.
In order to fulfill the requirement for phase-coupled signal sources, signal
generation is digitally implemented.
For this, the CMC 356 employs a high-performance digital signal processor
(DSP).
With digital signal generation the system is very flexible. An exact correction
of the amplitude, offset, and phase can be carried out in a digital manner
through the use of device-specific parameters (i.e., gain, offset, and null
phase angle on every channel).
The digital correction assures the best possible long-term drift behavior.
In addition to sine waves, any other periodic or transient signal can be
generated.
4.2.1 Accuracy and Signal Quality
The CMC 356 is a very precise test set with excellent long-term and
temperature drift behavior.
To achieve this accuracy, the philosophy was not only to solve signal
generation digitally, but also to implement the distribution of signals to the
various modules using digital methods. In doing so, the goal of galvanic
separation of the individual generator groups was also achieved without loss
of accuracy.
In achieving the amplitude accuracy, the drift behavior (temperature and
long-term) is of major importance in the voltage references, the digital-
analog converters (DAC), the accurate voltage dividers in the voltage
amplifiers, and the current shunts in the current amplifiers.
The actual (typical) data is in general about a factor of 3 better than the
guaranteed data.
The associated exact measurement media are required for the assurance of
the accuracy in the production. The measurement media used by
OMICRON are regularly calibrated by an accredited calibration institute so
that tracing to international standards can be assured.