Analogue-digital converting apparatus

Claim 2

An analog-digital converting apparatus comprising, integrator means; input means; reference voltage means; level detecting means having means for detecting levels at the output of the integrator means; controller means operative alternately to introduce into the integrator means voltage from the input means, and responsive to the integrator reaching a first fixed level to add to the input voltage an opposing reference voltage from said reference voltage means to bring the integrator level down toward a second level; a source of counting pulses; digital counting means operative to count said pulses during intervals while the integrator means is integrating the input voltage together with the opposing reference voltage to accumulate a first digital quantity; means for converting a residual level of the integrator means to a second digital quantity, said controller means being operative after a fixed time has elapsed to apply the existing residual integrator level to said converting means; and means including said counting means to combine said first and second digital quantities to obtain a digital output.

Claim 3

An analog-digital converting apparatus comprising, integrator means; input means, reference voltage means operative to deliver at least two reference voltages of different levels; level detecting means for detecting levels at the output of the integrator means; controller means operative to introduce into the integrator means voltage from the input means, and responsive to the integrator reaching certain levels as determined by said detecting means to add to the input voltage opposing reference voltages from said reference voltage means to bring the integrator level down toward its initial starting level; a source of counting pulses having aT least two different pulse rates proportioned as said different reference voltage levels; and digital counting means operative to count pulses during integration only when a reference voltage is being integrated, the pulse counting rate being determined by the level of a reference voltage being integrated; said controller means being operative after a fixed time has elapsed to remove the input voltage from the integrator means while coupling the references voltages thereto and count the counting pulses until the integrator level reaches its initial starting level.

Claim 4

An analog-digital converting apparatus comprising, integrator means; input means, reference voltage means operative to deliver at least two reference voltages of different levels; level detecting means for detecting levels at the output of the integrator means; controller means operative to introduce into the integrator means voltage from the input means, and responsive to the integrator reaching certain levels as determined by said detecting means to add to the input voltage opposing reference voltages from said reference voltage means to bring the integrator level down toward its initial starting level; a source of counting pulses having aT least two different pulse rates proportioned as said different reference voltage levels; and digital counting means operative to count pulses during integration only when a reference voltage is being integrated, the pulse counting rate being determined by the level of a reference voltage being integrated; said controller means being operative after a fixed time has elapsed to remove the input voltage from the integrator means while coupling the references voltages thereto and count the counting pulses until the integrator level reaches its initial starting level.

Claim 5

In an analog-digital converting apparatus as set forth in claim 2, gate means for coupling said counting pulses to said counting means, said gate means and said controller means being actuated synchronously by said counting pulses respectively to open the gate means while adding to the integrator input corresponding reference voltage levels.