Analog-to-digital conversion method and system with correction of analog gain and offset

Claim 1

A method for converting an analog signal to digital data using a sample-and-hold circuit which samples and holds the analog signal with a predetermined sampling frequency, an amplifier for amplifying an output of the sample-and-hold circuit, and an analog-to-digital converter for converting an output of the amplifier to digital data, said method comprising the steps of: supplying a reference analog signal to the analog-to-digital converter via the sample-and-hold circuit and the amplifier so as to obtain digital data corresponding to the reference analog signal; comparing the obtained digital data corresponding to the reference analog signal with predetermined reference data; determining a coefficient so that a product of said digital data corresponding to the reference analog signal and the coefficient is equal to said reference data on the basis of the comparison result; supplying an analog signal which is to be converted to digital data to said analog-to-digital converter via said sample-and-hold circuit and said amplifier so as to convert the analog signal to digital data; and producing a product of the obtained digital data and said coefficient and outputting the product as digital data corresponding to said analog signal.

Claim 2

A method for converting an analog signal to digital data using a sample-and-hold circuit which samples and holds the analog signal with a predetermined sampling frequency, an amplifier for amplifying an output of the sample-and-hold circuit, and an analog-to-digital converter for converting an output of the amplifier to digital data, said method comprising the steps of: supplying a reference analog signal to the analog-to-digital converter via the sample-and-hold circuit and the amplifier so as to obtain digital data corresponding to the reference analog signal; comparing the obtained digital data corresponding to the reference analog signal with predetermined reference data; determining a coefficient so that a product of said digital data corresponding to the reference analog signal and the coefficient is equal to said reference data on the basis of the comparison result; supplying an analog signal which is to be converted to digital data to said analog-to-digital converter via said sample-and-hold circuit and said amplifier so as to convert the analog signal to digital data; and producing a product of the obtained digital data and said coefficient and outputting the product as digital data corresponding to said analog signal.

Claim 3

A system for converting an analog signal to digital data comprising: a sample-and-hold circuit which samples and holds an analog signal with a predetermined sampling frequency; an amplifier for amplifying an output of said sample-and-hold circuit; an analog-to-digital converter for converting an output of said amplifier to digital data; means for supplying a reference signal to said analog-to-digital converter via said sample-and-hold circuit and said amplifier so as to obtain digital data corresponding to the reference analog signal; means for comparing the obtained digital data corresponding to the reference analog signal with predetermined reference data; means for determining a coefficient so that a product of said digital data corresponding to the reference analog signal and the coefficient is equal to said reference data on the basis of the comparison result; and means for multiplying digital data outputted from said analog-to-digital converter in correspondence with an analog signal supplied to said sample-and-hold circuit by said coefficient, and outputting the product as digital data corresponding to said analog signal supplied to said sample-and-hold circuit.

Claim 4

A system for converting an analog signal to digital data comprising: a sample-and-hold circuit which samples and holds an analog signal with a predetermined sampling frequency; an amplifier for amplifying an output of said sample-and-hold circuit; an analog-to-digital converter for converting an output of said amplifier to digital data; means for supplying a reference signal to said analog-to-digital converter via said sample-and-hold circuit and said amplifier so as to obtain digital data corresponding to the reference analog signal; means for comparing the obtained digital data corresponding to the reference analog signal with predetermined reference data; means for determining a coefficient so that a product of said digital data corresponding to the reference analog signal and the coefficient is equal to said reference data on the basis of the comparison result; and means for multiplying digital data outputted from said analog-to-digital converter in correspondence with an analog signal supplied to said sample-and-hold circuit by said coefficient, and outputting the product as digital data corresponding to said analog signal supplied to said sample-and-hold circuit.