Croma24 Service Manual
tor) register in the gate array which sets the duty cycle to make adjustments to the Carrier Assembly speed. A linear optical encoder is used to monitor the Carrier Assembly position.
The optical encoder strip runs the length of the Stabilizer Bracket and contains 150 lines and spaces per inch. Thus there are 300 edges per inch. The detector circuit actually consists of two optical edge detectors. They are separated from each other by one half the width of one of the optical lines on the encoder strip. This allows 4 evenly spaced pulses to be developed for each line on the encoder strip. This is known as quadrature signals. It gives an effective resolution of 600 lines per inch. See Figure
Figure 2-8. Quadrature Signal Generation.
THEORY OF OPERATION
Theory of Operation | 35 |
