Fully parallel threshold type analog-to-digital converter

Claim 2

A fully parallel threshold type A/D converter for an input signal having a predetermined voltage range, comprising: A plurality of comparators each of which has a fixed reference voltage corresponding to a quantizing level and which are disposed in parallel with each other, said comparators being divided into a plurality of blocks; and a sub comparator operatively associated with each of said comparator blocks, whereby the input signal is first compared by the sub-comparators and then compared by the comparators in one comparator block selected and supplied with power in response to the output from the associated sub-comparator, said reference voltages encompassing the full range of said input signal and remaining unchanged during the operation of both the sub-comparators and the comparators of said converter.

Claim 3

A parallel threshold type A/D converter as set forth in claim 1 wherein during the holding period of the comparators, the comparison by the sub-comparators for the next conversion cycle and the switching of operating current of said comparators are carried out; and the comparison by the sub-comparators is started immediately after the holding is started and after a predetermined time delay said switching is started.

Claim 4

A fully parallel threshold type A/D converter for an input signal having a predetermined voltage range, comprising: a plurality of comparators each of which has a fixed reference voltage corresponding to a quantizing level and which are disposed in parallel with each other, said comparators being divided into a plurality of blocks, the relative numbers of comparators in said blocks being weighted in a ratio corresponding to the variations in level of a sinusoidal signal wave within the corresponding intervals; and a sub-comparator operatively associated with each of said comparator blocks, whereby the input signal is first compared by the sub-comparators and then compared by the comparators in one comparator block selected and supplied with power in response to the output from the associated sub-comparator, said reference voltages encompassing the full range of said input signal and remaining unchanged during the operation of both the sub-comparators and the comparators of said converter.

Claim 5

A fully parallel threshold type A/D converter for an input signal having a predetermined voltage range, comprising: a plurality of comparators each of which has a fixed reference voltage corresponding to a quantizing level and which are disposed in parallel with each other, said comparators being divided into a plurality of blocks, the relative numbers of comparators in said blocks being weighted in a ratio corresponding to the variations in level of a sinusoidal signal wave within the corresponding intervals; and a sub-comparator operatively associated with each of said comparator blocks, whereby the input signal is first compared by the sub-comparators and then compared by the comparators in one comparator block selected and supplied with power in response to the output from the associated sub-comparator, said reference voltages encompassing the full range of said input signal and remaining unchanged during the operation of both the sub-comparators and the comparators of said converter.

Claim 6

A fully parallel threshold type analog-to-digital converter for an input signal having a predetermined voltage range, comprising: a plurality of comparators connected in parallel; means for supplying each comparator with a different fixed quantizing level reference voltage and an analog input signal to be compared therewith, said reference voltages spanning the range of anticipated values of said input signal in a number of groups, each group of reference voltages being associated with a corresponding block of comparators; at least three sub-comparators connected in parallel with said comparators, the number of sub-comparators being at least equal to the number of comparator blocks minus one; means for supplying each sub-comparator with a different fixed quantizing level reference voltage and said input signal to be compared therewith, the reference voltage supplied to each sub-comparator corresponding to the reference voltage applied to a comparator at an extreme of a corresponding block, so that the outputs of said sub-comparators uniquely define the particular block including a comparator with a reference voltage corresponding to the value of the input signal; said reference voltages encompassing the full range of said input signal and remaining unchanged during the operation of both the sub-comparators and the comparators of said converter; means responsive to the outputs of said sub-comparators for supplying power to the comparators of said particular block; and logic and encoding means responsive to the comparator outputs for providing a digital code signal having a value corresponding to the value of said analog input signal.

Claim 7

A fully parallel threshold type analog-to-digital converter for an input signal having a predetermined voltage range, comprising: a plurality of comparators connected in parallel; means for supplying each comparator with a different fixed quantizing level reference voltage and an analog input signal to be compared therewith, said reference voltages spanning the range of anticipated values of said input signal in a number of groups, each group of reference voltages being associated with a corresponding block of comparators; at least three sub-comparators connected in parallel with said comparators, the number of sub-comparators being at least equal to the number of comparator blocks minus one; means for supplying each sub-comparator with a different fixed quantizing level reference voltage and said input signal to be compared therewith, the reference voltage supplied to each sub-comparator corresponding to the reference voltage applied to a comparator at an extreme of a corresponding block, so that the outputs of said sub-comparators uniquely define the particular block including a comparator with a reference voltage corresponding to the value of the input signal; said reference voltages encompassing the full range of said input signal and remaining unchanged during the operation of both the sub-comparators and the comparators of said converter; means responsive to the outputs of said sub-comparators for supplying power to the comparators of said particular block; and logic and encoding means responsive to the comparator outputs for providing a digital code signal having a value corresponding to the value of said analog input signal.