Patent ID: 8396578

Claim:
A mixing circuit for mixing digital audio signals, comprising: a plurality of input-side integrated circuits cascade-connected in series and arranged on a main circuit board, and at least one output-side integrated circuit cascade-connected after the last one of the input-side integrated circuits in the series and arranged on the main circuit board, each of said input-side integrated circuits comprising: a microprogram memory that stores microprograms of a predetermined number H of steps; a signal processing section that performs signal processing on inputted digital audio signals of J channels, by executing the microprograms stored in said microprogram memory every sampling period, and thereby outputs processed digital audio signals of the J channels; a reception section that receives, from the preceding input-side integrated circuit in the series, digital audio signals of a predetermined number K of buses; a mixing section that mixes, for each of K buses, the digital audio signals of J channels from said signal processing section and corresponding one of the digital audio signals of K buses received by said reception section, and thereby outputs mixed digital audio signals of K buses; and a transmission section that transmits, to the succeeding input-side or output-side integrated circuit, the mixed digital audio signals of K buses outputted by said mixing section, said output-side integrated circuit comprising: a reception section that receives the mixed digital audio signals of K buses from the input-side integrated circuit preceding and connected to said output-side integrated circuit; a microprogram memory that stores microprograms of a predetermined number H of steps; and a signal processing section that performs signal processing on all or a part of the digital audio signals of K buses, received by said reception section, by executing the microprogram stored in said microprogram memory every sampling period, and thereby outputs the processed digital audio signals to an outside, wherein a number of input channels in said mixing circuit depends on the number of the cascade-connected input-side integrated circuits.