JPS578454A - Detecting circuit for signal level - Google Patents

Abstract

PURPOSE:To eliminate the need for separate provision of level meters and make constitution simple by allowing a light emitting element to emit light by the output of a voltage-frequency converter of which the frequency decreases with an increase in input voltage. CONSTITUTION:When the movable contactor 1m of a mixer monitor select switch 1 is turned and is touched to the fixing terminal 1b-1 of a channel, the signal output of the channel inputs to a level detector 2. When the signal output thereof is below a reference level, the oscillation frequency of a voltage-frequency converter 3 is about 100Hz, and when this level rises above the reference, the oscillation frequency lowers to about several Hz. The output of the converter 3 is supplied to a logic circuit 4, and when the output signal level is below the reference level, a light emitting display element 5 display ''2'' in a lighting state, and when it is above the reference level, the element displays ''2'' in a flickering state. Thereby, a level meter is abolished and this is substituted by the light emitting element of the channel, thus the constitution is made simple.