X381: Difference between revisions
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and the electrical signals are fed to the nixie controller ICs. | and the electrical signals are fed to the nixie controller ICs. | ||
Thus, as the vernier sweep speed knob is rotated, the digital display on the front panel follows it. | Thus, as the vernier sweep speed knob is rotated, the digital display on the front panel follows it. | ||
The rotary optical encoder produces two encodings at each rotational position. | |||
One encoding is in terms of TIME/DIV. | |||
The other encoding is in terms of Hz of a waveform that repeats within a given number of horizontal divisions, e.g., 10 divisions. | |||
The appropriate encoding is selected based on the position of the front panel SEC/Hz two-position switch, | |||
Meanwhile, a precision potentiometer is attached to the main encoder shaft. | Meanwhile, a precision potentiometer is attached to the main encoder shaft. | ||
This potentiometer functions in essentially the same way as the vernier sweep speed | This potentiometer functions in essentially the same way as the vernier sweep speed | ||
on a conventional timebase plug-in such as a [[3B1]]. | on a conventional timebase plug-in such as a [[3B1]]. | ||
The function of this potentiometer is not affected by the position of the front panel SEC/Hz two-position switch. | |||
When the rotary optical encoder is at the end of a revolution, | When the rotary optical encoder is at the end of a revolution, | ||
an optical signal (one track on the encoder disk) calls for a step of the | an optical signal (one track on the encoder disk) calls for a step of the | ||
the 1-2-5 rotary sweep speed switch that is concentric with the vernier sweep speed knob. | the 1-2-5 rotary sweep speed switch that is concentric with the vernier sweep speed knob. | ||
A motor and gears rotate the rotary switch. | A motor and gears rotate the rotary switch. | ||
The position of the main encoder shaft (and corresponding pattern of fiber illumination) | The position of the main encoder shaft (and corresponding pattern of fiber illumination) | ||
is insufficient to disambiguate which direction to rotate the 1-2-5 sweep speed switch. | is insufficient to disambiguate which direction to rotate the 1-2-5 sweep speed switch. | ||