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functions for variable sweep time, automatic scaling, and taking statistical data. Provide for a synchronization input which triggers the scope to start the sweep. Also, provide for automatic triggering based on certain input signals.

SAWTOOTH WAVEFORM (RAMP) GENERATOR

KEYWORDS: Real time, waveform generator

Figure SG-la shows an example of a ramp function, output(t), and Figure SG- lb shows the error which results from an approximation to the ramp function by a step function.

PROBLEM STATEMENT

Design a sawtooth waveform (i.e., a ramp) generator with the peak amplitude for the function constant at one (i.e., normalized).

SOLUTION

The characteristics of a single sawtooth waveform generator, shown in Figure SG-2 will be examined to introduce concepts common to many waveform generators. The generator is basically a register in a DMgpa which holds the value output(t), to which an input increment (a slope), delta, is added modulo 2^16. The value of delta (where 1 < delta < 2^16) is added to output at ts second intervals. The value for output is transferred to a T(digital-to-analog) at the sample intervals. The following characteristics can be formulated for the generator:

 

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