| 摘要 |
PURPOSE:To improve the scale read accuracy to much extent by applying Y modulation which makes the signals that compensate the vertical position of the scale to overlap with vertical scanning sawtooth type wave signals and forming overlapped raster section with high brightness. CONSTITUTION:A vertical scanning sawtooth type wave signal generator 2 is provided. This signal eV is supplied to a deflection circuit 7 which excites the vertical deflection coil 5 of a microscope 3 and the deflection coil 12 of a cathode-ray tube 8 through the first addition circuit 28. Besides, this signal is supplied to the input ends of comparison circuits 19 and 20 which configure the second gate circuit G2 and a signal inverter 24 which configures the fourth gate circuit G4. The output from the fourth gate circuit G4 is supplied to the input end of the first addition circuit 28, and adds the vertical signal eV and the signal eF of the circuit G4. It also supplies an output signal eG to a CRT vertical deflection coil 10. As a result, even when a scale overlaps a sample picture, the scale can easily be read and read accuracy be improved to much extent. |
