Plural delta-sigma converters operating in parallel with independent dither generators

Claim 2

A signal conversion system for converting an analog input signal to a digital output signal by employing the delta-sigma modulation technique, said signal conversion system comprising: input means for receiving an analog input signal to be converted to a digital signal; a plurality of analog-digital delta-sigma converters connected in parallel to said input means for respectively receiving the analog input signal therefrom at the input of each of said plurality of analog-digital delta-sigma converters; each said analog-digital delta-sigma converter including a quantizer for converting the analog input signal into a digital signal representative thereof, each of said quantizers producing quantization noise in converting the analog input signal into a digital signal; a plurality of dither generators corresponding to the plurality of analog-digital delta-sigma converters to provide a respective dither generator for each of said analog-digital delta-sigma converters, each said dither generator utilizing random variables unrelated to the respective random variables utilized by the other dither generators for producing a dither output signal having a spectrum distribution of noise concentrated in a region of relatively high frequency to define a colored noise signal and being connected to the quantizer of said analog-digital delta-sigma converter corresponding thereto; and an adder connected in parallel to the outputs of each of said plurality of analog-digital delta-sigma converters for providing an output signal as a digital output signal comprising the added outputs of said plurality of analog-digital delta-sigma converters; whereby the addition of the colored noise signals produced by the plurality of different dither generators as included in the outputs of said plurality of analog-digital delta-sigma converters effectively averages the quantization noise to provide an approximation of a white noise signal such that an improved dynamic range over a wide frequency band region is achievable for a relatively low frequency region by the signal conversion system.

Claim 3

A signal conversion system as set forth in claim 1, further including a bandpass filter interposed between each said dither generator and the quantizer of the analog-digital delta-sigma converter corresponding thereto and interconnecting the respective dither generator to the corresponding analog-digital delta-sigma converter for concentrating the colored noise signal from the dither generator in the relatively high frequency region.

Claim 4

A signal conversion system as set forth in claim 2, wherein the region in which the spectrum distribution of the colored noise signal is concentrated by the respective bandpass filter corresponding to each of said plurality of dither generators is in the range of 120 KHz-200 KHz.

Claim 5

A signal conversion system for converting a digital input signal to an analog output signal by employing the delta-sigma modulation technique, said signal conversion system comprising: input means for receiving a digital input signal to be converted to an analog signal; a plurality of digital-analog delta-sigma converters connected in parallel to said input means for respectively receiving the digital input signal therefrom at the input of each of said plurality of digital-analog delta-sigma converters; each said digital-analog delta-sigma converter including a quantizer for converting the digital input signal into an analog signal representative thereof, each of said quantizers producing quantization noise in converting the digital input signal into an analog signal; a plurality of dither generators corresponding to the plurality of digital-analog delta-sigma converters to provide a respective dither generator for each of said digital-analog delta-sigma converters, each said dither generator utilizing random variables unrelated to the respective random variables utilized by the other dither generators for producing a dither output signal having a spectrum distribution of noise concentrated in a region of relatively high frequency to define a colored noise signal and being connected to the quantizer of said digital-analog delta-sigma converter corresponding thereto; and an adder connected in parallel to the outputs of each of said plurality of digital-analog delta-sigma converters for providing an output signal as an analog output signal comprising the added outputs of said plurality of digital-analog delta-sigma converters; whereby the addition of the colored noise signals produced by the plurality of different dither generators as included in the outputs of said plurality of digital-analog delta-sigma converters effectively averages the quantization noise to provide an approximation of a white noise signal such that an improved dynamic range over a wide frequency band region is achievable for a relatively low frequency region by the signal conversion system.

Claim 6

A signal conversion system for converting a digital input signal to an analog output signal by employing the delta-sigma modulation technique, said signal conversion system comprising: input means for receiving a digital input signal to be converted to an analog signal; a plurality of digital-analog delta-sigma converters connected in parallel to said input means for respectively receiving the digital input signal therefrom at the input of each of said plurality of digital-analog delta-sigma converters; each said digital-analog delta-sigma converter including a quantizer for converting the digital input signal into an analog signal representative thereof, each of said quantizers producing quantization noise in converting the digital input signal into an analog signal; a plurality of dither generators corresponding to the plurality of digital-analog delta-sigma converters to provide a respective dither generator for each of said digital-analog delta-sigma converters, each said dither generator utilizing random variables unrelated to the respective random variables utilized by the other dither generators for producing a dither output signal having a spectrum distribution of noise concentrated in a region of relatively high frequency to define a colored noise signal and being connected to the quantizer of said digital-analog delta-sigma converter corresponding thereto; and an adder connected in parallel to the outputs of each of said plurality of digital-analog delta-sigma converters for providing an output signal as an analog output signal comprising the added outputs of said plurality of digital-analog delta-sigma converters; whereby the addition of the colored noise signals produced by the plurality of different dither generators as included in the outputs of said plurality of digital-analog delta-sigma converters effectively averages the quantization noise to provide an approximation of a white noise signal such that an improved dynamic range over a wide frequency band region is achievable for a relatively low frequency region by the signal conversion system.

Claim 7

A signal conversion system as set forth in claim 4, further including a bandpass filter interposed between each said dither generator and the quantizer of the digital-analog delta-sigma converter corresponding thereto and interconnecting the respective dither generator to the corresponding digital-analog delta-sigma converter for concentrating the colored noise signal from the dither generator in the relatively high frequency region.

Claim 8

A signal conversion system as set forth in claim 5, wherein the region in which the spectrum distribution of the colored noise signal is concentrated by the respective bandpass filter corresponding to each of said plurality of dither generators is in the range of 120 KHz-200 KHz.

Claim 9

A signal conversion system as set forth in claim 4, further including a low pass filter connected to the output of said adder for filtering the analog output signal provided at the output of said adder.