US 4,227,048 AGranted

Audio signal transmission circuit having a constant level tone-controlled output signal

AssigneeNippon Gakki Seizo Kabushiki Kaisha

InventorYuuichi Nagata

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Abstract

An audio signal transmission circuit comprising a first variable attenuator (i.e. volume controller) from which a level-adjusted audio signal is derived, a tone control circuit connected to the output of the first variable attenuator and supplying a tone-controlled audio signal to a loudspeaker, and a second variable attenuator connected between the tone control circuit and a record terminal and feeding the tone-controlled audio signal to the record terminal. The first and second variable attenuators are mechanically interlocked and arranged in such a way that the sum of their attenuating factors remains constant irrespective of any attenuating operation. At the record terminal there can be obtained the tone-controlled audio output signal with a substantially constant level (amplitude level), irrespective of the level adjusting operation of the signal to the loudspeaker.

Claims9

Dependent claims

An audio signal transmission circuit comprising:

an input terminal for receiving an audio input signal;
a first output terminal for delivering a first output signal;
a second output terminal for delivering a second output signal;
a tone control circuit having an output which is coupled to said first output terminal, said tone control circuit supplying a tone controlled signal at its output;
first variable attenuating means connected between said input terminal and the input of said tone control circuit, the output of said first variable attenuating means having a variable signal level;
and
second variable attenuating means connected between the output of said tone control circuit and said second output terminal for supplying a tone controlled output signal of said tone control circuit to said second output terminal, said first and second attenuating means being interlocked and so designed that the sum of their attenuating factors is substantially constant irrespective of any attenuating operation of said first and second variable attenuating means so that the tone controlled signal at said second output terminal has a substantially constant level.

4 more elements

Dependencies are inferred from the claim text.