Digital signal processing apparatus and digital signal processing method

• US 20060071833A1
• Filed: 09/07/2005
• Published: 04/06/2006
• Est. Priority Date: 09/16/2004
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Suzuki, Nobukazu, Ichimura, Gen, Noguchi, Masayoshi
• Granted Patent: US 7,215,262 B2
• Time in Patent Office: Days
• US Class Current: 341/143
• CPC Class Codes: G06F 7/602 using delta-sigma sequences
• CPC Class Codes: H03M 7/3028 the quantiser being a single bit one
• CPC Class Codes: H03M 7/304 with distributed feedback, i.e. with feedback paths from the quantiser output to more than one filter stage

Abstract

The present invention provides a digital signal processing apparatus which can perform batch processing of mixing and gain controlling, etc., one time while the frequency characteristics of different filters are being mixed to a plurality of input signals in case of the re-quantization only once. The present invention provides 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, which includes a plurality of integrating unit, 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 unit, 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 the output of the integrating unit of the front stage, the output of the feedforward arithmetic unit and the output of the feedback arithmetic unit and supplies the mixed result to the integrating unit of the rear stage.

Claims

1. 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 means;

a plurality of feedforward arithmetic means for supplying an arithmetic result calculated based on an independent feedforward coefficient to each input signal, to each of the plurality of the integrating means;

quantizing means for quantizing the integrated output outputted from one of the plurality of the integrating means;

a plurality of feedback arithmetic means for supplying an arithmetic result obtained by calculating quantized data outputted from the quantizing means based on the independent feedback coefficient, to each of the plurality of the integrating means; and

mixing means for mixing the output of the integrating means of the front stage, the output of the feedforward arithmetic means and the output of the feedback arithmetic means and supplying the mixed result to the integrating means of the rear stage.

2. The digital signal processing apparatus according to claim 1, further comprising:

a sigma section corresponding to the number of the plurality of the input signals; and

one delta section.

3. The digital signal processing apparatus according to claim 1, further comprising:

a gain control function by setting the coefficients.

4. 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:

integrating means having a plurality of integrators;

quantization means for subjecting an integrated output from the integrating means to quantization processing;

a plurality of feedforward arithmetic means for 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 means; and

a plurality of feedback arithmetic means for performing arithmetic processing on the quantized output from the quantization means using feedback coefficients to feed back an arithmetic result to the integrating means, by using the approximately obtained feedforward coefficients of the plurality of systems and feedback coefficients.

5. The digital signal processing apparatus according to claim 4, wherein the delta sigma modulator comprises a sigma section corresponding to the number of the plurality of the input signals, and one delta section.

6. The digital signal processing apparatus according to claim 4, wherein the delta sigma modulator further performs a gain control function for controlling a gain.

7. The digital signal processing apparatus according to claim 4, wherein the approximately obtained feedforward coefficients of the plurality of the systems and feedback coefficients are written in storage means, and its value is loaded to the coefficient of the delta sigma modulator by a control signal, etc.

8. 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 arithemtic 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.

9. The digital signal processing method according to claim 8, further comprising:

a first transfer function calculating step of calculating the transfer function of at least one filter function which causes the plurality of input signals to have different frequency characteristics;

a second transfer function calculating step of calculating the transfer function of a tertiary noise shaper;

a first approximate coefficient calculating step of calculating an approximate coefficient corresponding to the feedforward coefficient by a sigma step corresponding to the number of the plurality of the input signals;

a second approximate coefficient calculating step of calculating the approximate coefficient corresponding to the feedback coefficient by one delta step;

a feedforward coefficient calculating step of calculating the feedback coefficient from the first approximate coefficient calculated by the first approximate coefficient calculating step; and

a feedback coefficient calculating step of calculating the feedback coefficient from the second approximate coefficient calculated by the second approximate coefficient calculating step.

10. The digital signal processing method according to claim 8, wherein the gain control function is further performed to control the gain.

11. 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 unit;

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 unit;

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 the output of the integrating unit of the front stage, the output of the feedforward arithmetic unit and the output of the feedback arithmetic unit and supplies the mixed result to the integrating unit of the rear stage.

12. 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.