| 摘要 |
<p>The frequency scale calibration system for radio equipment and instruments uses a photo-sensitive film for the scale which is exposed at intervals to an electronic flash tube. A frequency spectrum generator is connected to the input of the equipment whose tuning mechanism is motor-driven through an electromagnetic clutch. The IF output at, e.g. 100 kHz intervals of the selected frequency band is used to trigger the flash tube and control the aperture of an adjustable slot shutter so that short and long graduations at the required frequency intervals are impressed on the scale. A photo-detector provides a control pulse at each flash for a counter and logic unit. In the event of flash failure, the control decouples the drive to the tuning stage.</p> |
