Waveform Generators
Features, Functions, and Options
Amplitude
The output level of the Instrument may be programmed from 20mV to 20Vp-p into high impedance, or 10mV to 10V into 50 Ω. Offset may be applied to the output to shift the signal either positive or negative. Offset and amplitude are inter-related, so make sure you understand the offset-amplitude ranges before you apply offset to your signal. A special fine offset generator is built into each channel, which allows programming of extremely small offset increments. This feature extends the offset resolution to 6 digits and is very useful in applications such as mixer balancing where few micro-volts could sway the balance either way.
Trigger Modes
Besides its normal continuous mode, the Instrument responds to a variety of trigger sources. The output waveform may be gated, triggered, or generate a counted burst of waveforms. A built-in trigger generator, having a programmable period can be used as a replacement of an external trigger source. The internal trigger generator can be programmed with resolution of 7 digits.
Arbitrary Waveforms
The Instrument generates arbitrary waveforms with 14 bits of vertical resolution. Any waveform it generates must first be downloaded to waveform memory. The arbitrary waveform memory is a bank of 14-bit words. Each word represents a point on the horizontal waveform scale. Each word has a horizontal address that can range from 0 to 1,048,576 for the 396 (0 to 4,191,280 for the 397) and a vertical address that can range from -8192 to +8191 (14 bits). Using a high speed clocking circuit, the digital contents of the arbitrary waveform memory are extracted and routed to the Digital to Analog Converter (DAC). The DAC converts the digital data to an analog signal, and the output amplifier completes the task by amplifying or attenuating the signal at the output connector.
Memory Segmentation
There is no need to use the complete memory every time an arbitrary waveform is generated. Waveform memory can be divided into up to 4096 smaller segments and different waveforms can be loaded into each segment. The various segments may then be loaded into a sequence table to generate long and complex waveforms. The sequence table can link up to 4096 segments for the 396 (2048 for the 397), while each segment can loop up to 1 million times.
Remote Control
The Instrument must be used in conjunction with a host computer. All of its functions, modes and parameters are fully programmable using SCPI commands and syntax. There are three ways to program the Instrument, the first being low-level programming of each individual parameter using SCPI commands. The second alternative is to use ArbExplorer for high-level programming. ArbExplorer is a software package supplied with the Instrument that simulates a set of mechanical front panels. It has all the necessary push buttons, displays and dials to operate the Instrument as if you were using it on the bench. The third alternative is using application specific drivers, such LabVIEW or IVI.
The Instrument must be programmed to generate waveforms. Therefore, it is recommended that the user becomes familiar with its basic features, functions and programming concepts as described fully in the Users Manual.
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