| 摘要 |
PURPOSE:To permit a circuit of simple constitution to measure a horizontal leading-in range fP and a holding range fH of TV by providing a measurement selection switch to the input part of a sample holding device which inputs a pulse obtained by a pulse-width converting circuit for adjusting the output pulse width of a voltage comparator. CONSTITUTION:A horizontal oscillation pulse varied repeatedly at the period T of a triangular wave voltage is outputted to a horizontal oscillation output terminal 13 and supplied to a frequency-voltage converter 22. Its output DC voltage is applied to one-side inputs of two voltage comparators 23 and 24. The measurement selection switch 29 is provided to select measurements of four points, i.e. the lower-limit and upper-limit values of the ranges fP and fH independently. The pulse-width converting circuit 30 sets an input sampling signal to a sample holding device 31 to an adequate width for accurate measurements of the ranges fP and fH. When this input sampling pulse is applied, the sample holding device 31 operates and functions to hold itself at a DC voltage conforming to the time axis of the input sampling pulse at this time. |
