| 摘要 |
PURPOSE:To detect abnormality of the oscillator simply, by coupling outputs of plural oscillators to connect them to a diode and by comparing the detected synthesized output with high and low reference levels and by combining these comparison outputs. CONSTITUTION:Output terminals of oscillators 1 and 2 are coupled and connected to diode 3, and synthesized oscillation output signal (a) is detected, and the level of detection output signal (b) is compared with high and low reference levels by comparing means 4 and 5 such as level comparators. At this time, if the level of detection output signal (b) and reference levels of level comparators 4 and 5 are denoted as V1, VH and VL respectively and relation V1>VH>VL is set, detection signals (c) and (d) in the normal state become 1. When one of oscillators 1 and 2 becomes step-out, detection signal (c) becomes 0 and detection signal (d) becomes 1; and when oscillation outputs are lowered, detection signals (c) and (d) become 0, and thus, abnormality of oscillators is detected on the basis of combinations of detection signals. |
