I began to suspect the problem I noticed previously with the spiral ramp circuit getting locked when the in / out control voltages exceeded only slightly above 5V was due to the way I was conducting the test. Recent investigation showed this to be the case. The new voltage projection circuit gives data the full 10V range, and suddenly a huge improvement in anything involving spirals has appeared. The unwinding eye shape I remember from run like hell, see photos, appeared, and now the variable spiral rate input feels useful in the way I expect it was intended to be, due to the control voltage ranges finally being correct enough.
It can be seen in the photos that circuitry for inverse spirals, diamonds, sweep and direction have been removed from the breadboard, as these functions were previously moved to software. The time of the long awaited testing of the ramp shaping circuit is approaching.
Interesting to note: The spiral ramp reset function actually requires two inputs which are always either / or as controlled by the reset bit. By controlling the inputs separately, a spiral mode unavailable on the original board is obtained where reset high freezes the ramp where it is, and reset low permits the ramp to proceed from where it was stopped rather than resetting.
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Originally Posted by laserist
