Method and means for processing an analog signal from a diode array

A method for determining an illumination state of an "n"-point photodiode array having a plurality of addressing diodes, a plurality of unions, said unions connecting said addressing diodes in series relationship, and "n" photoresponsive means each having two terminals, one of said terminals each being connected to successive unions and the other being connected to a common terminus, said method comprising:

• applying a swept voltage between said series of addressing diodes and said terminus thereby producing a current in series relationship with said voltage;
• converting said current to a first signal proportional thereto;
• integrating said first signal during "n" successive time windows to provide a value for each window;
• subtracting from each window value the value from the previous window to provide a set of "n" result values;
• and
• converting each of said result values to a digital value, wherein said digital values represent the illumination state of said "n"-point photodiode array.

A circuit for determining an illumination state of an "n"-point photodiode array having a plurality of addressing diodes, a plurality of unions, said unions connecting said addressing diodes in series relationship, and "n" photoresponsive means each having two terminals, one of said terminals each being connected to successive unions and the other being connected to a common terminus, said circuit comprising:

• means for applying a swept voltage between said series of addressing diodes and said terminus thereby producing a current in series relationship with said voltage;
• means for converting said current to a first signal proportional in amplitude thereto;
• means for differentiating said first signal to provide a second signal;
• means for sampling the amplitude of said second signal at each of "n" times during the voltage sweep to provide "n" amplitude values;
• and
• means for converting each of said amplitude values to a digital value, wherein said digital values represent the illumination state of said "n"-point photo diode array.

A circuit for determining an illumination state of an "n"-point photodiode array having a plurality of addressing diodes, a plurality of unions, said unions connecting said addressing diodes in series relationship, and "n" photoresponsive means each having two terminals, one of said terminals each being connected to successive unions and the other being connected to a common terminus, said circuit comprising:

• means for applying a swept voltage between said series of addressing diodes and said terminus thereby producing a current in series relationship with said voltage;
• means for converting said current to a first signal proportional in amplitude thereto;
• means for integrating said first signal during "n" successive time windows to provide a value for each window;
• means for subtracting from each window value the value from the previous window to provide a set of "n" result values;
• and
• means for converting each of said result values to a digital value, wherein said digital values represent the illumination state of said "n"-point photodiode array.