| 摘要 |
A trace coloring system enhances signal information that is provided to a user of a signal measurement device, for example, a digitizing oscilloscope or spectrum analyzer, having a color display for displaying graphical depictions of electrical signals. Trace coloring logic (hardware, software, or a combination thereof) colors a trace with different colors, each indicating a corresponding range of signal values. As an example, in the context of an oscilloscope, the trace may be colored with various colors to visually indicate which areas of the trace correspond to particular logic levels. A first color may be allocated to a logic low ("0"), a second color to a logic high ("1"), a third color to an indeterminate range that is between logic low and high, and a fourth color to an extreme value that is outside a desired or acceptable predefined logic range. In the preferred embodiment, the trace coloring logic is implemented in software that is executed by a processor. A frame buffer is interfaced with the processor. The frame buffer stores display data including a word for each pixel. Optionally, prepainting logic may be employed in the trace coloring logic. The prepainting logic assigns color values to pixels of the trace based upon locations of the pixels within the display map. When prepainting is employed, the frame buffer is preferably video random access memory (VRAM) configured to permit modification of bits of each word, while masking other bits of each word, so that updating of each word can be accomplished in a single access operation to the memory.
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