Analog-to-digital conversion for processing wide-range and non-linear input signals

Claim 3

The method of claim 1 comprising the further steps of displaying said digital signal output in scientific notation form comprising a decimal number corresponding to the first significant digit of the value of said monitored physical parameter and an exponent number representative of the order of magnitude of said digit.

Claim 4

The method of claim 1 wherein there are 10 incremental amplitude levels in said sets.

Claim 5

The method of claim 1 wherein said stepping staircase signal is generated, starting from zero amplitude, by providing a first group of steps having a first incremental amplitude spacing and thereafter providing a second group of steps having a second incremental amplitude spacing, said second set being superimposed on a first base amplitude level.

Claim 6

The method of claim 4 further characterized in that the generation of said staircase signal beyond the last step of said second group is provided by a third group of steps having a third incremental amplitude spacing, said third set being superimposed on a second base amplitude level.

Claim 9

Apparatus for converting a non-linear analog signal, representing the value of a monitored physical parameter, into a digital signal corresponding to said value comprising: a. generator means, including a digital counter coupled to a digital-to-analog converter, for generating an analog staircase signal which increases sequentially in stepped incremental levels, b. means for grouping said incremental levels into spaced sets of consecutive, equally-spaced amplitude levels, c. means for adjusting the spacing between incremental levEls within each set of said staircase signal to approximate the non-linear response characteristic of said analog signal to said monitored physical parameter, d. comparator means for comparing the amplitude of said analog signal to be converted to the amplitude of said staircase signal and generating an output signal when substantial parity between the two signals is reached, said comparator output signal causing said digital counter to cease counting and to hold its output at the digital value which produces substantial parity in said comparator, and e. read-out means for displaying a numerical representation of said counter output.

Claim 10

Apparatus for converting a non-linear analog signal, representing the value of a monitored physical parameter, into a digital signal corresponding to said value comprising: a. generator means, including a digital counter coupled to a digital-to-analog converter, for generating an analog staircase signal which increases sequentially in stepped incremental levels, b. means for grouping said incremental levels into spaced sets of consecutive, equally-spaced amplitude levels, c. means for adjusting the spacing between incremental levEls within each set of said staircase signal to approximate the non-linear response characteristic of said analog signal to said monitored physical parameter, d. comparator means for comparing the amplitude of said analog signal to be converted to the amplitude of said staircase signal and generating an output signal when substantial parity between the two signals is reached, said comparator output signal causing said digital counter to cease counting and to hold its output at the digital value which produces substantial parity in said comparator, and e. read-out means for displaying a numerical representation of said counter output.

Claim 11

The converter apparatus set forth in claim 7 further characterized in that said numerical representation displayed by said read-out means comprises a decimal number corresponding to the first significant digit of the value of said monitored physical parameter and a number representative of the order of magnitude of said digit.

Claim 12

The converter apparatus of claim 7 wherein said means (c) for adjusting the spacing between incremental levels within a set comprises selectable resistor means connecting the output of said digital-to-analog converter to a summing circuit, and said means (b) for grouping said incremental levels into spaced sets comprises selectable current levels of predetermined amplitudes connected to said summing circuit.

Claim 13

The converter apparatus set forth in claim 8 wherein said digital counter is a decade counter and said number displayed by said read-out device which is representative of the order of magnitude of said first significant digit is derived by circuit means for counting the number of decade cycles said digital counter means completes before an output signal is produced by said comparator means.

Claim 14

The converter apparatus of claim 10 wherein said circuit means for counting the decade cycles of said digital counter controls the selection of said resistor means and said current levels associated with a respective decade of said digital counter.

Claim 15

The converter apparatus of claim 11 further provided with means for resetting to zero said digital counter and said circuit means for counting the decade cycles of said counter.

Claim 18

Apparatus as set forth in claim 13 wherein said decimal number corresponding to said first significant digit is generated by means which include a staircase signal generator, and a comparator for comparing the respective amplitudes of said staircase signal generator and said analog signal.

Claim 19

Apparatus as set forth in claim 14 wherein said staircase generator provides an output signal which increases sequentially in stepped increments from a reference level, with said increments being grouped into sets, and said exponent number is determined by the provision of means for counting the number of completed sets occurring in said staircase signal generator before substantial parity between the compared signals is reached in said comparator.

Claim 20

Apparatus for converting an analog signal representing a monitored value which may vary over a range of more than one order of magnitude into a digital signal comprising: a. staircase generator means for producing an analog signal which increases sequentially in stepped incremental levels; b. means for grouping said incremental levels into a plurality of consecutive sets of equally-spaced sequentially-incrementing amplitude levels; c. comparator means for comparing the amplitude of said aNalog signal to be converted to the amplitude of said sequentially-increasing amplitude level and producing an output signal when substantial parity between the two amplitudes is reached; d. first digital counter means for counting said incremental levels within each respective set of amplitude levels as sequentially produced by said generator means until said comparator output signal has been generated; e. second digital counter means for counting the number of said sets of amplitude levels produced by said generator means until said comparator output signal has been generated; and f. readout means for displaying both the output of said first digital counter as a decimal number corresponding to the first significant digit of said monitored value and the output of second digital counter as a decimal number corresponding to the order of magnitude of said monitored value.

Claim 21

Apparatus for converting an analog signal representing a monitored value which may vary over a range of more than one order of magnitude into a digital signal comprising: a. staircase generator means for producing an analog signal which increases sequentially in stepped incremental levels; b. means for grouping said incremental levels into a plurality of consecutive sets of equally-spaced sequentially-incrementing amplitude levels; c. comparator means for comparing the amplitude of said aNalog signal to be converted to the amplitude of said sequentially-increasing amplitude level and producing an output signal when substantial parity between the two amplitudes is reached; d. first digital counter means for counting said incremental levels within each respective set of amplitude levels as sequentially produced by said generator means until said comparator output signal has been generated; e. second digital counter means for counting the number of said sets of amplitude levels produced by said generator means until said comparator output signal has been generated; and f. readout means for displaying both the output of said first digital counter as a decimal number corresponding to the first significant digit of said monitored value and the output of second digital counter as a decimal number corresponding to the order of magnitude of said monitored value.

Claim 22

Apparatus set forth in claim 16 further provided with means for varying the rate of increase of said incremental levels for each respective set of amplitude levels.

Claim 23

Apparatus set forth in claim 17 further provided with means to dynamically select a different predetermined rate of increase of said incremental level for each respective set of amplitude levels.