Hybrid function generator for optical sensing systems

Claim 2

A hybrid digital-to-analog function generator for generating an analogue voltage which is a nonlinear function of an input digital signal comprising: a. first and second digital-to-analog converters each having a digital input D for receiving an input digital signal, a highreference voltage input Eo for receiving an analogue voltage, a low-reference voltage input Ei for receiving an analogue voltage, and an analogue voltage output V, where V D (Eo Ei) + Ei; b. a first voltage source operatively connected to said highreference voltage input of said first digital-to-analog converter; c. a second voltage source operatively connected to said lowreference voltage input of said first digital-to-analog converter; d. means for connecting said analogue voltage output of said first digital-to-analog converter to said high-reference voltage input of said second digital-to-analog converter; and e. means for connecting the digital input signal to the digital input of said first and second digital-to-analog converter, the output of said second digital-to-analog converter being the analogue voltage output of said function generator.

Claim 3

The function generator recited in claim 1 wherein said means for connecting the output of said first digital-to-analog converter to the high-reference voltage input of said second digital-to-analog converter comprises an amplifier.

Claim 4

a first voltage source operatively connected to said high-reference voltage input of said first digital-to-analog converter;

Claim 5

a first voltage source operatively connected to said high-reference voltage input of said first digital-to-analog converter;

Claim 6

a second voltage source operatively connected to said low-reference voltage input of said first digital-to-analog converter;

Claim 7

a second voltage source operatively connected to said low-reference voltage input of said first digital-to-analog converter;

Claim 8

The function generator recited in claim 1 further comprising a third voltage source operatively connected to said low-reference voltage input of said second digital-to-analog converter.

Claim 9

The function generator recited in claim 1 further comprising: a. voltage-summing means having first and second inputs, said first input being operatively connected to the output of said second digital-to-analog converter; and b. a third reference voltage source operatively connected to said second input of said voltage summing means the output of said voltage-summing means being the analogue voltage output of the function generator.

Claim 10

means for connecting said analogue voltage output of said first digital-to-analog converter to said high-reference voltage input of said second digital-to-analog converter; and

Claim 11

means for connecting said analogue voltage output of said first digital-to-analog converter to said high-reference voltage input of said second digital-to-analog converter; and

Claim 12

means for connecting the digital input signal to the digital input of said first and second digital-to-analog converter, the output of said second digital-to-analog converter being the analogue voltage output of said function generator.

Claim 13

means for connecting the digital input signal to the digital input of said first and second digital-to-analog converter, the output of said second digital-to-analog converter being the analogue voltage output of said function generator.

Claim 14

The function generator recited in claim 1 wherein said first aNd second voltage sources comprise constant voltage sources.

Claim 15

The function generator recited in claim 3 wherein said first voltage source is a variable voltage source.

Claim 16

The function generator recited in claim 6 wherein said variable voltage source comprises voltage-summing means having a first fixed voltage as a first input and a percentage of the output voltage from said function generator as a second input.

Claim 17

A hybrid digital-to-analog function generator for generating an analogue voltage which is a nonlinear function of an input digital signal comprising: a. a digital-to-analog converter having a digital input D for receiving an input digital signal, a high-reference voltage input Eo for receiving an analogue voltage, a low-reference voltage input Ei for receiving an analogue voltage, and an analogue voltage output V, where V D (Eo - Ei) + Ei; b. a first, fixed voltage source operatively connected to said high-reference voltage input; c. a second variable voltage source connected to said low-reference voltage input; and d. means for connecting the input digital signal to said digital input.

Claim 18

A hybrid digital-to-analog function generator for generating an analogue voltage which is a nonlinear function of an input digital signal comprising: a. a digital-to-analog converter having a digital input D for receiving an input digital signal, a high-reference voltage input Eo for receiving an analogue voltage, a low-reference voltage input Ei for receiving an analogue voltage, and an analogue voltage output V, where V D (Eo - Ei) + Ei; b. a first, fixed voltage source operatively connected to said high-reference voltage input; c. a second variable voltage source connected to said low-reference voltage input; and d. means for connecting the input digital signal to said digital input.

Claim 19

The function generator recited in claim 8 wherein said variable voltage source comprises a voltage divider operatively connected to said analogue voltage output.

Claim 20

A hybrid digital-to-analog function generator for generating an analogue voltage which is a nonlinear function of an input digital signal comprising: a. a digital-to-analog converter having a digital input D for receiving an input digital signal, a high-reference voltage input Eo for receiving an analogue voltage, a low-reference voltage input Ei for receiving an analogue voltage, and an analogue voltage output V, where V D (Eo - Ei) + Ei; b. a first, fixed voltage source operatively connected to said low reference voltage input; c. a variable voltage source operatively connected to said high-reference voltage input; and d. means for connecting the input digital signal to said digital input.

Claim 21

A hybrid digital-to-analog function generator for generating an analogue voltage which is a nonlinear function of an input digital signal comprising: a. a digital-to-analog converter having a digital input D for receiving an input digital signal, a high-reference voltage input Eo for receiving an analogue voltage, a low-reference voltage input Ei for receiving an analogue voltage, and an analogue voltage output V, where V D (Eo - Ei) + Ei; b. a first, fixed voltage source operatively connected to said low reference voltage input; c. a variable voltage source operatively connected to said high-reference voltage input; and d. means for connecting the input digital signal to said digital input.

Claim 22

The function generator recited in claim 10 wherein said variable voltage source comprises voltage-summing means having a fixed voltage source connected to a first input and a percentage of the voltage at said analogue voltage output connected to a second input.

Claim 23

A hybrid digital-to-analog function generator for generating an analogue voltage which is a nonlinear function of an input digital signal comprising: a. first and second digital-to-analog converter each having a digital input D for receiving an input digital signal, a high-reference voltage input Eo for receiving an analogue voltage, a low-reference voltage input Ei for receiving an analogue voltage, and an analogue voltage output V, where V D (Eo -Ei) + Ei; b. first voltage-summing means having first and second inputs and an output operatively connected to said high-reference voltage input of said first digital-to-analog converter; c. a first fixed voltage source operatively connected to said first input of said voltage-summing means; d. a voltage divider operatively connected to said analogue voltage output of said second digital-to-analog converter, the output of said voltage divider being operatively connected to said second input of said voltage-summing means; e. a second fixed voltage source operatively connected to said low-reference voltage input of said first digital-to-analog converter; f. means for connecting said analogue voltage output of said first digital-to-analog to said high-reference voltage input of said second digital-to-analog converter; and g. means for connecting the input digital signal to said digital inputs of said first and second digital-to-analog converters.

Claim 24

A hybrid digital-to-analog function generator for generating an analogue voltage which is a nonlinear function of an input digital signal comprising: a. first and second digital-to-analog converter each having a digital input D for receiving an input digital signal, a high-reference voltage input Eo for receiving an analogue voltage, a low-reference voltage input Ei for receiving an analogue voltage, and an analogue voltage output V, where V D (Eo -Ei) + Ei; b. first voltage-summing means having first and second inputs and an output operatively connected to said high-reference voltage input of said first digital-to-analog converter; c. a first fixed voltage source operatively connected to said first input of said voltage-summing means; d. a voltage divider operatively connected to said analogue voltage output of said second digital-to-analog converter, the output of said voltage divider being operatively connected to said second input of said voltage-summing means; e. a second fixed voltage source operatively connected to said low-reference voltage input of said first digital-to-analog converter; f. means for connecting said analogue voltage output of said first digital-to-analog to said high-reference voltage input of said second digital-to-analog converter; and g. means for connecting the input digital signal to said digital inputs of said first and second digital-to-analog converters.

Claim 25

The function generator recited in claim 12 further comprising: a. second voltage-summing means having first and second inputs; b. a third fixed voltage source connected to said first input of said second voltage-summing means; and, c. said analogue voltage output of said second digital-to-analog converter connected to said second input of said second voltage-summing means.

Claim 28

The method as recited in claim 14 comprising the additional step of adding a third analogue voltage to the output of said second digital-to-analog converter.

Claim 31

The method recited in claim 16 wherein the step of supplying a variable reference voltage to said low-reference voltage input comprises feeding a percentage of the output of said digital-to-analog converter to said low-reference voltage input.

Claim 34

The method recited in claim 18 wherein the step of supplying a variable reference voltage to said high-reference voltage input comprises feeding the sum of a second fixed reference voltage plus a percentage of the output of said digital-to-analog converter to said high-reference voltage input.

Claim 35

A measuring system for generating a digital number indicative of the characteristic being measured, comprising: a. a sensor for generating an analogue voltage indication of the desired characteristic; b. a comparator having first and second inputs, the output of said sensor being operatively connected to said first input of said sensor; c. a count control circuit having an input operatively connected to the output of said comparator whereby said count control circuit assumes a first state when said first input of said comparator is greater than said second input and assumes a second state when said second input of said comparator is greater than said first input; d. a reversible digital counter operatively connected to the output of said comparator; and e. a hybrid function generator operatively connected to the output of said counter, the output of said function generator being operatively connected to said second input of said comparator, said function generator comprising:

Claim 36

A measuring system for generating a digital number indicative of the characteristic being measured, comprising: a. a sensor for generating an analogue voltage indication of the desired characteristic; b. a comparator having first and second inputs, the output of said sensor being operatively connected to said first input of said sensor; c. a count control circuit having an input operatively connected to the output of said comparator whereby said count control circuit assumes a first state when said first input of said comparator is greater than said second input and assumes a second state when said second input of said comparator is greater than said first input; d. a reversible digital counter operatively connected to the output of said comparator; and e. a hybrid function generator operatively connected to the output of said counter, the output of said function generator being operatively connected to said second input of said comparator, said function generator comprising:

Claim 37

The measuring system recited in claim 20 wherein said sensor comprises a radiation source and a radiation detector.

Claim 38

The measuring system recited in claim 21 wherein said radiation source comprises a light source and said radiation detector comprises a photocell.