| 摘要 |
PURPOSE:To confirm the mutual relation between an input and a muting level clearly and easily and to facilitate the setting of the muting level by switching and displaying the input level and muting level on one display means. CONSTITUTION:The output of a 1F circuit 3 is converted by a rectifying circuit 10 and supplied to a comparing circuit 12 to obtain an output corresponding to an input signal. The comparing circuit 12 is supplied with a reference value corresponding to the set value of the muting level. Therefore, the comparing circuit 12 generates an output according to whether the signal level from the rectifying circuit 10 is larger than the reference value or not. The reference value is set by a variable resistor 13. A switch 17 for switching the display means is provided, and when the muting level is set, the switch is placed at the side of a contact (b) and the resistor 13 is varied by looking at a meter to set the muting level to a desired level. The switch is placed normally at the side of a contact (a) to display the signal level on the meter. When the muting level is checked during reception, the switch is switched to the side (b) to display the current set level on the meter. |
