| 摘要 |
PURPOSE:To set the sound volume optionally and also to prevent the generation of noise by supplying the digital output signal of a sound level setting switch to a D/A converter in an emergency broadcast reception mode and outputting the sound volume control voltage equivalent to a designated sound level to a sound amplifier. CONSTITUTION:When the emergency broadcast is received and an emergency broadcast detecting signal is supplied to a control signal input terminal 4, a data selector 23 selects the level data 20-23 set by a sound level setting switch 22 for emergency broadcast, etc. These selected level data are outputted to a D/A converter 24. The converter 24 converts the sound volume data 0-3 corresponding to the data 20-23 into analog signals by the clock signal T supplied from a sound volume control part 21. These analog signals are supplied to a sound amplifier 8 in the form of the sound volume control voltage V1. The amplifier 8 amplifies the sound signals supplied to the sound signal input terminals 1-1' by the sound volume control voltage V1 and outputs them to a sound output terminal 9 to output them in voice through a speaker.
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