Gain ranging analog-to-digital converter with error correction

A digital microphone system, comprising:

• a microphone transducer for receiving an audible input signal and converting it to an analog signal;
• and
• a digital processing system for converting said analog signal to a digital signal and processing the digital signal in the digital domain with a conversion gain, said digital processing system during the conversion of said analog signal to said digital signal operable to detect the magnitude of the audible input signal and vary said conversion gain as a function of the magnitude of the audible input signal, and wherein said digital processing system includes the operation of combining at least two digital signals to yield a resulting digital signal, with the combining operation including a phase equalization operation performed between the two combined signals to minimize distortion in the resulting digital signal;
• wherein said digital processor includes an analog-to-digital (A/D) converter for performing the conversion of said analog signal to said digital signal, said A/D converter including:
• a high gain path for receiving the input analog signal and imparting a first gain thereto;
• a low gain path for receiving the input analog signal and imparting a second gain thereto, said second gain lower than said first gain;
• a gain varying device for varying the gain in at least one of said paths relative to the other of said paths;
• a summing device for summing the output of said high gain path and said low gain path;
• a device for controlling the operation of said gain varying device to determine the amount of signal to be summed from each of said high and low gain paths in accordance with a predetermined summing profile;
• and
• an equalizer for adjusting the phase between said high and low gain paths to minimize distortion in the resulting signal.

A gain ranging analog-to-digital (A/D) converter, comprising:

• a high gain conversion path for receiving an analog input signal and converting it to a digital signal with a first gain;
• a low gain path for receiving the analog input signal and converting it to a digital signal with a second gain, said second gain lower than said first gain;
• a gain varying device for varying the gain in at least one of said paths relative to the other of said paths;
• a summing device for summing the output of said high gain path and said low gain path;
• a device for controlling said gain varying device to determine the amount of signal to be summed from each of said high and low gain paths in accordance with a predetermined summing profile;
• and
• an equalizer for adjusting the phase between said high and low gain paths to minimize distortion in the resulting signal.

A method for digitally processing information in a microphone system, comprising:

• receiving at a microphone transducer an audible input signal and converting it to an analog signal;
• converting in a digital processing system the analog signal to a digital signal;
• and
• processing the digital signal in the digital domain with a conversion gain, wherein the step of converting during the conversion of the analog signal to the digital signal operable to detect the magnitude of the audible input signal and vary the conversion gain as a function of the magnitude of the audible input signal, and wherein the step of converting includes the step of combining at least two digital signals prior to the step of varying the conversion gain to yield a resulting digital signal, with the combining operation including a phase equalization operation performed between the two combined signals to minimize distortion in the resulting digital signal.

A method for digitally processing information in a microphone system, comprising:

• receiving at a microphone transducer an audible input signal and converting it to an analog signal;
• converting in a digital processing system the analog signal to a digital signal;
• and
• processing the digital signal in the digital domain with a conversion gain, wherein the step of converting during the conversion of the analog signal to the digital signal operable to detect the magnitude of the audible input signal and vary the conversion gain as a function of the magnitude of the audible input signal, and wherein the step of converting includes the step of combining at least two digital signals to yield a resulting digital signal, with the combining operation including a phase equalization operation performed between the two combined signals to minimize distortion in the resulting digital signal;
• wherein the step of converting includes the step of performing the conversion of the analog signal to the digital signal with an analog-to-digital (A/D) converter, including the steps of:
• providing a high gain path for receiving the input analog signal and imparting a first gain thereto;
• providing a low gain path for receiving the input analog signal and imparting a second gain thereto, the second gain lower than the first gain;
• varying the gain in at least one of the paths relative to the other of the paths;
• summing the output of the high gain path and the low gain path;
• controlling the operation of the step of varying to determine the amount of signal to be summed from each of the high and low gain paths in accordance with a predetermined summing profile;
• and
• adjusting the phase between the high and low gain paths to minimize distortion in the resulting signal.

A gain ranging method for application in an analog-to-digital (A/D) converter, comprising the steps of:

• receiving an analog input signal in a high gain conversion path and converting it to a digital signal with a first gain;
• receiving the analog input signal in a low gain path and converting it to a digital signal with a second gain, the second gain lower than the first gain;
• varying the gain with a gain varying device in at least one of the paths relative to the other of the paths;
• summing the output of the high gain path and the low gain path;
• controlling the gain varying device to determine the amount of signal to be summed from each of the high and low gain paths in accordance with a predetermined summing profile;
• and
• adjusting the phase between the high and low gain paths to minimize distortion in the resulting signal.