Interpolative readout apparatus

Claim 2

In a system employing a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which is related to two preselectable reference voltages in the same manner as the signal voltage provided by said measuring circuit in response to the test sample is related to two calibration voltages, said readout apparatus comprising: at least a pair of adjustable output voltage reference sources; at least a pair of calibration voltage circuits, each of said calibration voltage circuits being adjustable to provide a calibration voltage at a level corresponding to the signal voltage provided by said sample measuring circuit in response to a respective calibration value; a first interpolation switching circuit which is adapted to repetitively switch between the two calibration voltages thereby to provide an average voltage which is between the two calibration voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said switching circuit, including servo loop means for varying the switching duty cycle to adjust said average voltage to a value corresponding to the signal voltage provided by said sample measuring circuit when a test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two output voltage reference sources thereby to provide an output voltage whose average value is related to the two reference source voltages in the same manner as the average voltage provided by said first switching circuit is related to the two calibration voltages.

Claim 3

In a system employing a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which is related to two preselectable reference voltages in the same manner as the signal voltage provided by said measuring circuit in response to the test sample is related to two calibration voltages, said readout apparatus comprising: at least a pair of adjustable output voltage reference sources; at least a pair of calibration voltage circuits, each of said calibration voltage circuits being adjustable to provide a calibration voltage at a level corresponding to the signal voltage provided by said sample measuring circuit in response to a respective calibration value; a first interpolation switching circuit which is adapted to repetitively switch between the two calibration voltages thereby to provide an average voltage which is between the two calibration voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said switching circuit, including servo loop means for varying the switching duty cycle to adjust said average voltage to a value corresponding to the signal voltage provided by said sample measuring circuit when a test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two output voltage reference sources thereby to provide an output voltage whose average value is related to the two reference source voltages in the same manner as the average voltage provided by said first switching circuit is related to the two calibration voltages.

Claim 4

In a system employing a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which is related to two preselectable reference voltages in the same manner as the signal voltage provided by said measuring circuit in response to the test sample is related to two calibration voltages, said readout apparatus comprising: at least a pair of adjustable output voltage reference sources; at least a pair of calibration voltage circuits, each of said calibration voltage circuits being adjustable to provide a calibration voltage at a level corresponding to the signal voltage provided by said sample measuring circuit in response to a respective calibration value; a first interpolation switching circuit which is adapted to repetitively switch between the two calibration voltages thereby to provide an average voltage which is between the two calibration voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said switching circuit, including servo loop means for varying the switching duty cycle to adjust said average voltage to a value corresponding to the signal voltage provided by said sample measuring circuit when a test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two output voltage reference sources thereby to provide an output voltage whose average value is related to the two reference source voltages in the same manner as the average voltage provided by said first switching circuit is related to the two calibration voltages.

Claim 5

In a system employIng a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which is related to two preselectable reference voltages in the same manner as the signal voltage provided by said measuring circuit in response to the test sample is related to two signal voltages provided the same said measuring circuit in response to respective calibration samples, said apparatus comprising: at least a pair of adjustable output voltage reference sources; at least a pair of calibration voltage storage circuits; means for setting the calibration voltage held by each of said storage circuits to a level corresponding to the signal voltage provided by said sample measuring circuit in response to a respective calibration sample; a first interpolation switching circuit which is adapted to repetitively switch between the two voltages held by said storage circuits thereby to provide an average voltage which is between the two stored voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said switching circuit including servo loop means for varying the switching duty cycle to provide an average voltage having a value corresponding to the signal voltage provided by said sample measuring circuit when a test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two output voltage reference sources thereby to provide an output voltage whose average value is related to the two reference source voltages in the same manner as the average voltage provided by said first switching circuit is related to the two stored calibration voltages.

Claim 6

In a system employIng a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which is related to two preselectable reference voltages in the same manner as the signal voltage provided by said measuring circuit in response to the test sample is related to two signal voltages provided the same said measuring circuit in response to respective calibration samples, said apparatus comprising: at least a pair of adjustable output voltage reference sources; at least a pair of calibration voltage storage circuits; means for setting the calibration voltage held by each of said storage circuits to a level corresponding to the signal voltage provided by said sample measuring circuit in response to a respective calibration sample; a first interpolation switching circuit which is adapted to repetitively switch between the two voltages held by said storage circuits thereby to provide an average voltage which is between the two stored voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said switching circuit including servo loop means for varying the switching duty cycle to provide an average voltage having a value corresponding to the signal voltage provided by said sample measuring circuit when a test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two output voltage reference sources thereby to provide an output voltage whose average value is related to the two reference source voltages in the same manner as the average voltage provided by said first switching circuit is related to the two stored calibration voltages.

Claim 7

Readout apparatus as set forth in claim 2 wherein said adjustable output voltage reference sources comprise manually adjustable potentiometers.

Claim 8

Readout apparatus as set forth in claim 2 wherein said calibration voltage storage circuits comprise integrator circuits having leakage time constants which are relatively long with respect to the operating cycle of said system.

Claim 9

Readout apparatus as set forth in claim 2 wherein said calibration voltage storage circuits comprise sample and hold circuits which sample when respective calibration samples are being measured by the sample measuring circuit.

Claim 10

Readout apparatus as set forth in claim 2 wherein said first and second interpolation switching circuits comprise reed relays.

Claim 11

Readout apparatus as set forth in claim 2 wherein said first and second interpolation switching circuits each comprise a pair of transistors which are alternately energized.

Claim 12

Readout apparatus as set forth in claim 2 wherein each of said interpolation switching circuits includes a low pass filter and the switching circuit operates to apply the respective pair of voltages alternately to said filter and said filter provides an essentially d.c. voltage which lies between the respective pair of voltages at a value which is variable as a function of the duty cycle of the switching.

Claim 13

Readout apparatus as set forth in claim 2 wherein said means for repetitively operating said switching circuit comprises: a triangular wave generator; means for generating an error signal which is a function of the difference between the signal voltage provided by said sample measuring circuit and the average voltage provided by said first interpolation switching circuit; means for comparing the amplitude of the error signal with the instantaneous value of the waveform provided by said triangular wave generator and for controlling said first switching circuit to select a first one of said stored voltages when the error signal exceeds the triangular waveform voltage and to select the other of said stored voltages when the triangular waveform voLtage exceeds the error signal.

Claim 14

Readout apparatus as set forth in claim 2 further comprising: an upper limit voltage reference source; a lower limit voltage reference source; means for comparing the average value of the output voltage provided by said second interpolation switching circuit with each of the limit voltages provided by said limit voltage reference sources; and means for providing an alarm signal if the average value of the output voltage generated by said second interpolation switching circuit is not between the two limit voltages when a preconstructed mid-range calibration sample is being measured by said sample measuring circuit.

Claim 15

In a system employing a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which is related to two preselectable reference voltages in the same manner as the signal voltage provided by said measuring circuit in response to the test sample is related to two signal voltages provided the same said measuring circuit in response to respective calibration samples, said apparatus comprising: at least a pair of adjustable output voltage reference sources; at least a pair of sample and hold calibration voltage storage circuits each of which employs feedback means for setting the respective voltage held to a level corresponding to the signal voltage provided by said sample measuring circuit during measurement of a respective calibration sample; a first interpolation switching circuit which is adapted to repetitively switch between the two voltages held by said storage circuits thereby to provide an average voltage which is between the two stored voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said switching circuit including servo loop means for varying the switching duty cycle to provide an average voltage having a value corresponding to the signal voltage provided by said sample measuring circuit when a test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two output voltage reference sources thereby to provide an output voltage whose average value is related to the two reference source voltages in the same manner as the average voltage provided by said first switching circuit is related to the two stored calibration voltages.

Claim 16

In a system employing a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which is related to two preselectable reference voltages in the same manner as the signal voltage provided by said measuring circuit in response to the test sample is related to two signal voltages provided the same said measuring circuit in response to respective calibration samples, said apparatus comprising: at least a pair of adjustable output voltage reference sources; at least a pair of sample and hold calibration voltage storage circuits each of which employs feedback means for setting the respective voltage held to a level corresponding to the signal voltage provided by said sample measuring circuit during measurement of a respective calibration sample; a first interpolation switching circuit which is adapted to repetitively switch between the two voltages held by said storage circuits thereby to provide an average voltage which is between the two stored voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said switching circuit including servo loop means for varying the switching duty cycle to provide an average voltage having a value corresponding to the signal voltage provided by said sample measuring circuit when a test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two output voltage reference sources thereby to provide an output voltage whose average value is related to the two reference source voltages in the same manner as the average voltage provided by said first switching circuit is related to the two stored calibration voltages.

Claim 17

In a system employing a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which is related to two preselectable reference voltages in the same manner as the signal voltage provided by said measuring circuit in response to the test sample is related to two signal voltages provided the same said measuring circuit in response to respective calibration samples, said apparatus comprising: a plurality of calibration voltage storage circuits; means for setting the calibration voltage held by each of said storage circuits to a level corresponding to the signal voltage provided by said sample measuring circuit in response to a respective calibration sample; means for comparing the signal voltage provided by said sample measuring circuit when a test sample is being measured with successive ones of said stored calibration voltages and for selecting the pair of stored calibration voltages between which lies the value of the test sample signal voltage; a plurality of adjustable output voltage reference sources corresponding to said calibration voltage storage circuits; means for selecting the pair of output voltage reference sources corresponding to the selected stored calibratioN voltages; a first interpolation switching circuit which is adapted to repetitively switch between the two selected stored voltages thereby to provide an average voltage which is between the two selected stored voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said switching circuit including servo loop means for varying the switching duty cycle to provide an average voltage having a value corresponding to the signal voltage provided by said sample measuring circuit when the test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two selected output voltage reference sources thereby to provide an output voltage whose average value is related to the two reference source voltages in the same manner as the average voltage provided by said first switching circuit is related to the two stored calibration voltages.

Claim 18

In a system employing a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which is related to two preselectable reference voltages in the same manner as the signal voltage provided by said measuring circuit in response to the test sample is related to two signal voltages provided the same said measuring circuit in response to respective calibration samples, said apparatus comprising: a plurality of calibration voltage storage circuits; means for setting the calibration voltage held by each of said storage circuits to a level corresponding to the signal voltage provided by said sample measuring circuit in response to a respective calibration sample; means for comparing the signal voltage provided by said sample measuring circuit when a test sample is being measured with successive ones of said stored calibration voltages and for selecting the pair of stored calibration voltages between which lies the value of the test sample signal voltage; a plurality of adjustable output voltage reference sources corresponding to said calibration voltage storage circuits; means for selecting the pair of output voltage reference sources corresponding to the selected stored calibratioN voltages; a first interpolation switching circuit which is adapted to repetitively switch between the two selected stored voltages thereby to provide an average voltage which is between the two selected stored voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said switching circuit including servo loop means for varying the switching duty cycle to provide an average voltage having a value corresponding to the signal voltage provided by said sample measuring circuit when the test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two selected output voltage reference sources thereby to provide an output voltage whose average value is related to the two reference source voltages in the same manner as the average voltage provided by said first switching circuit is related to the two stored calibration voltages.

Claim 19

In a system employing a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which corresponds to two preselectable reference voltages as the signal voltage provided by said measuring circuit, in response to the test sample, corresponds to the signal voltages provided the same said measuring circuit in response to a pair of calibration samples, said apparatus comprising: a pair of adjustable output voltage reference sources; a pair of calibration voltage storage circuits; means for setting the calibration voltage held by each of said storage circuits to a level corresponding to the signal voltage provided by said sample measuring circuit in response to a respective calibration sample; means providing a first range defining voltage having a value which is a function of at least one of said stored voltages; means providing a second range defining voltage which is a function of one of the stored voltages and of the difference between the two stored voltages; a first interpolation switching circuit which is adapted to repetitively switch between the two range defining voltages thereby to provide an average voltage which is between the two range defining voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said first switching circuit including servo loop means for varying the switching duty cycle to provide an average voltage having a value proportional to the signal voltage provided by said sample measuring circuit when a test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two output voltage reference sources thereby to provide an output voltage whose average value is a function of the signal voltage provided by the measuring circuit in response to a test sample.

Claim 20

In a system employing a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which corresponds to two preselectable reference voltages as the signal voltage provided by said measuring circuit, in response to the test sample, corresponds to the signal voltages provided the same said measuring circuit in response to a pair of calibration samples, said apparatus comprising: a pair of adjustable output voltage reference sources; a pair of calibration voltage storage circuits; means for setting the calibration voltage held by each of said storage circuits to a level corresponding to the signal voltage provided by said sample measuring circuit in response to a respective calibration sample; means providing a first range defining voltage having a value which is a function of at least one of said stored voltages; means providing a second range defining voltage which is a function of one of the stored voltages and of the difference between the two stored voltages; a first interpolation switching circuit which is adapted to repetitively switch between the two range defining voltages thereby to provide an average voltage which is between the two range defining voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said first switching circuit including servo loop means for varying the switching duty cycle to provide an average voltage having a value proportional to the signal voltage provided by said sample measuring circuit when a test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two output voltage reference sources thereby to provide an output voltage whose average value is a function of the signal voltage provided by the measuring circuit in response to a test sample.

Claim 21

In a system employing a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which corresponds to two preselectable reference voltages as the signal voltage provided by said measuring circuit, in response to the test sample, corresponds to the signal voltages provided the same said measuring circuit in response to a pair of calibration samples, said apparatus comprising: a pair of calibration voltage storage circuits; switching means for selectively interconnecting said measuring circuit and said first storage circuit during measurement of a first calibration sample for storing a voltage, designated A, proportional to that produced by said measuring circuit in response to said First calibration sample and for selectively interconnecting said measuring circuit and said second storage circuit during measurement of a second calibration sample for storing a voltage, designated B, proportional to that produced by said measuring circuit in response to said second calibration sample; means interconnected with said first and second storage circuits for providing a first range defining voltage equal to A and second range defining voltage equal to B + k (B - A) where k is a preselected constant; first and second adjustable voltage sources providing preselectable voltages designated K and L respectively; means interconnected with said voltage sources for providing a first output limit voltage equal to K and a second output limit voltage equal to K + k (K - L); a first interpolation switching circuit which is adapted to repetitively switch between the two range defining voltages thereby to provide an average voltage which is between the two range defining voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said first switching circuit including servo loop means for varying the switching duty cycle to provide an average voltage having a value proportional to the signal voltage provided by said sample measuring circuit when a test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two output voltage limit voltages thereby to provide an output voltage whose average value corresponds to the two preselected voltages K and L as the signal voltage provided by the measuring circuit corresponds to the stored voltages A and B.

Claim 22

In a system employing a sample measuring circuit operative to provide a signal voltage which is a function of a sought characteristic of a sample being measured; readout apparatus for providing, in response to a test sample, an output voltage which corresponds to two preselectable reference voltages as the signal voltage provided by said measuring circuit, in response to the test sample, corresponds to the signal voltages provided the same said measuring circuit in response to a pair of calibration samples, said apparatus comprising: a pair of calibration voltage storage circuits; switching means for selectively interconnecting said measuring circuit and said first storage circuit during measurement of a first calibration sample for storing a voltage, designated A, proportional to that produced by said measuring circuit in response to said First calibration sample and for selectively interconnecting said measuring circuit and said second storage circuit during measurement of a second calibration sample for storing a voltage, designated B, proportional to that produced by said measuring circuit in response to said second calibration sample; means interconnected with said first and second storage circuits for providing a first range defining voltage equal to A and second range defining voltage equal to B + k (B - A) where k is a preselected constant; first and second adjustable voltage sources providing preselectable voltages designated K and L respectively; means interconnected with said voltage sources for providing a first output limit voltage equal to K and a second output limit voltage equal to K + k (K - L); a first interpolation switching circuit which is adapted to repetitively switch between the two range defining voltages thereby to provide an average voltage which is between the two range defining voltages at an interpolation point which is a function of the duty cycle of the switching; means for repetitively operating said first switching circuit including servo loop means for varying the switching duty cycle to provide an average voltage having a value proportional to the signal voltage provided by said sample measuring circuit when a test sample is being measured; and a second interpolation switching circuit which is operated in synchronism with said first interpolation switching circuit and which repetitively switches between the two output voltage limit voltages thereby to provide an output voltage whose average value corresponds to the two preselected voltages K and L as the signal voltage provided by the measuring circuit corresponds to the stored voltages A and B.