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similar to the over-modulation pattern of D, but close examination shows the difference. 1 e over-modulation pattern has straight sides and a narrow tip; the over-bias under-drive pattern has curved sides and a wider, sloping tipNot all the troubles are traceable to bias and drive- Parasitic* are frequently troublesome in AM rigs; even when they're absent under CW conditions, they may appear during portions ot the audio cycle and break the modulation up so badly that it's unreadable, . , ,
An example is shown in E; this ng is breaking into oscillation at the peaks of the audio cycle. Although the pattern is reasonably clean during most of the cycle, the sharp pip at the left indicates the oscillation; the on-the-air effect may range from "splatter" to complete unreliability, depending largely on the frequency of the parasitic.
Another example appears in F- This time, the oscillation starts as the audio cycle starts upward, but stops at the audio peak. The emitted signal would be completely unreadable.
Many such examples could be shown, but the most general way to look at it is this: if you get a pattern showing a sharp pip anywhere in it, look for a parasitic or two*
If the trapezoid pattern fails to show you what's wrong, the problem is probably distorted
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