Re: Tandberg 3000x annoying problem
The picture on the scope has to be misleading. It could be a waveform switching fast between two sine signals shown at a timebase speed where the switching isn't resolved. Unlikely to be created in a simple analogue tape recorder. Or it may be mis-triggering showing overlaid pictures by alternating between two trigger points - the scope failing to discriminate between rising and falling crossings of the trigger point. Most commonly this is caused by a glitch on a waveform or high frequency oscillation.
What it isn't is the scope simply showing that there are two signals exactly as there appear to be on one point at the same time. That would require one point to be at two different voltages at the same time. The scope display appears to show this, but if this is true, something has gone wrong with space/time/causality. As a new Dr Who series has just started, you must expect to be attacked by a guy in a rubber monster suit at any moment.
When you see a scope picture like that, if you don't have two separate traces switched on and overlaid on the screen, it's a big clue that there is something more to find by playing with scope settings. These are exactly the circumstances where the automatic setting algorithms now found on a lot of scopes get it wrong.
David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
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