Signal processing circuit in an audio device

DETAILED DESCRIPTION The present invention has been made in view of the above circumstances.
Accordingly, an object of the invention is to provide a signal processing circuit which changes amplification gain of the variable gain control section according to attack and release time constants determined by the audio signal level.
Signal processing operation thus provides audio signals which have less distortion than conventionally reproduced audio signals and which sound more natural.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, the signal processing circuit of the present invention comprises; a variable gain control section for providing a variable amplification gain to an input signal in response to a gain control signal, an input signal level detecting section for detecting a level of the input signal and for generating a corresponding detection signal, a time constant setting section for storing a plurality of time constant tables, each one of the plurality of time constant tables including a set of input signal delay characteristics corresponding to a predetermined level of the input signal, and a time constant selecting section for selecting one of the plurality of time constant tables in the time constant setting section in response to the detection signal, such that the gain control signal is determined by the selected one of the plurality of time constant tables and the amplification gain of the variable gain control section is varied according to the selected one of the plurality of time constant tables.