Digital signal processing apparatus and digital signal processing method

A digital signal processing method for performing a delta sigma modulation process on a plurality of input signals to output a 1-bit digital signal, executing at least a filter function which causes the plurality of input signals to have different frequency characteristics, and a mixing function which mixes the plurality of signals each having a different frequency characteristic due to the at least one filter function, by the steps comprising:

• an integrating step of performing integrating processing on the input signals using a plurality of integrators;
• a quantization step of subjecting an integrated output from the integrating step to quantization processing;
• a plurality of feedforward arithmetic steps of performing arithmetic processing on the plurality of input signals by using feedforward coefficients of a plurality of systems corresponding to the plurality of signals and supplying an arithmetic result to the integrating step;
• and
• a plurality of feedback arithmetic steps of performing arithmetic processing on the quantized output from the quantization step, using feedback coefficients to feed back an arithmetic result to the integrating step, by using the approximately obtained feedforward coefficients of the plurality of systems and feedback coefficients,
• wherein the at least one filter function includes a first infinite impulse response filter having an order n0 and a second infinite impulse response filter having an order n1, the mixing function includes a tertiary noise shaper having an order n2, and a number of the plurality of integrators is n0+n1+n2.

A digital signal processing apparatus for outputting a 1-bit digital signal by performing a delta sigma modulation process on a plurality of input signals, comprising:

• a plurality of integrating units;
• a plurality of feedforward arithmetic units that supply an arithmetic result calculated based on an independent feedforward coefficient to each input signal, to each of the plurality of the integrating units;
• a quantizing unit that quantizes the integrated output outputted from one of the plurality of the integrating units;
• a plurality of feedback arithmetic units that supply an arithmetic result obtained by calculating quantized data outputted from the quantizing unit based on the independent feedback coefficient, to each of the plurality of the integrating units;
• and
• a mixing unit that mixes an output of an integrating unit of a front stage, an output of the feedforward arithmetic unit and an output of the feedback arithmetic unit and supplies a mixed result to an integrating unit of a rear stages,
• wherein the front stage includes a first infinite impulse response filter having an order n0 and a second infinite impulse response filter having an order n1, the mixing unit has an order n2, and a number of the plurality of integrating units is n0+n1+n2.

A digital signal processing apparatus for outputting a 1-bit digital signal by performing a delta sigma modulation process on a plurality of input signals, executing at least a filter function which causes the plurality of input signals to have different frequency characteristics, and a mixing function which mixes the plurality of signals each having a different frequency characteristic due to the at least one filter function, by a delta sigma modulator comprising:

• an integrating unit having a plurality of integrators;
• a quantization unit that subjects an integrated output from the integrating unit to quantization processing;
• a plurality of feedforward arithmetic units that perform arithmetic processing on the plurality of input signals by using feedforward coefficients of a plurality of systems corresponding to the plurality of signals and supply an arithmetic result to the integrating unit;
• and
• a plurality of feedback arithmetic units that perform arithmetic processing on the quantized output from the quantization unit using feedback coefficients to feed back an arithmetic result to the integrating unit, by using the approximately obtained feedforward coefficients of the plurality of systems and feedback coefficients,
• wherein the at least one filter function includes a first infinite impulse response filter having an order n0 and a second infinite impulse response filter having an order n1, the mixing function includes a tertiary noise shaper having an order n2, and a number of the plurality of integrators is n0+n1+n2.