| 摘要 |
PURPOSE:To attain signal processing for a digital voice signal subjected to emphasis without converting the digital signal by forming the equipment with a linear IIR(infinite-impulse-response) having a specific transmission function. CONSTITUTION:The equipment is provided with a multiplier means 1 multiplying an input by 2<-1> and outputting the result, a multiplier means 2 multiplying an input by -2<-5> and outputting the result, adder means 3, 4 and a delay means 5 delaying the input by one clock whose frequency is the same as a symbol rate of an input signal IN of the de-emphasis equipment. The transmission function of this configuration is expressed in equation I as a linear IIR filter and constants of the equation I are respectively a1=2<-1>, b0=2<-1> and b1=2<-6>. Let the input IN be a binary digital voice signal whose amplitude characteristic has an emphasis characteristic expressed in equation II and whose sampling frequency is 2's complement of 32kHz. Thus, the multiplier processing in the digital signal processing is realized with a simple arithmetic operation such as a shift. |
