| 摘要 |
In a measuring arrangement for the spacing between a marking (32) on a displaceable marking carrier (30) and a reference line, to produce a high degree of resolution and a low scanning frequency, at least two electrodes (17, 18) defining a measuring gap (20) are provided on the inside of the end (9) of a cathode ray tube (1). The deflection unit (6) of the cathode ray tube is actuated in such a way that the impact spot (7) of the electron beam (4), which covers the measuring gap in the transverse direction, moves along the measuring gap on the end (9) of the tube, without external influence, in such a way that the difference between the currents which flow away from the two electrodes is of a predeterminable value. The marking carrier exerts on the electron beam an influence which varies when the marking carrier is displaced and by means of which the impact spot is displaced transversely with respect to the longitudinal direction of the measuring gap. That influence can be kept constant by the impact spot being moved along with the marking carrier. The actuating signal for the deflection unit, which is required for that purpose, provides a measurement in respect of the spacing being sought.
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