The Development of Bipolar IC's for dbx Noise Reduction System

The heart of the dbx noise reduction system has been newly integrated into two bipolar monolithic IC's. This paper describes the newly developed voltage controlled amplifier chip (VCA IC) and root mean square value level sensor chip (RMS IC) for dbx noise reduction system application. These IC's have achieved excellent performance : low total harmonic distortion 0.007% :low output noise level -94dbV :wide operating supply voltage ±4 V to ±15 V : wide dynamic range more than 100 dB. Using new VCA IC and RMS IC, the low cost dbx noise reduction system with high performance and several improvements can be fabricated compared with conventional discrete system. The detailes of the integrated circuit design of VCA and RMS are also discussed.