Sloping baseline compensation for a chromatographic analyzer
AssigneePhillips Petroleum Company
InventorLouis D. Kleiss
Life of this patent
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Abstract
A method and apparatus is disclosed for correcting errors in a chromatographic analysis wherein the trailing edge of a strong peak interferes with the integration of the trailing peak which follows the strong peak. In one embodiment of the invention two functions of the trailing peak are electrically integrated and summed to produce a correct peak integration. In a second embodiment of the invention the baseline is shifted and the integration of the trailing peak is performed with respect to the shifted baseline to produce a correct peak integration.
Claims7
Apparatus comprising:
- means for producing a first analog output signal having a varying voltage in time;
- a first integrating circuit adapted to integrate said first analog output signal over a period beginning at time t.sub.1 and ending at time t.sub.2 and adapted to establish a first signal representative of the results of the integration of said first analog output signal;
- means for correcting said first signal if the voltage level of said first analog output signal at said time t.sub.1 does not equal the level of said first analog output signal at said time t.sub.2, said means for correcting said first signal comprising:
- means for establishing a second signal representative of the time period t.sub.1 -t.sub.2 ;
- means for establishing a third signal representative of the difference between the voltage level of said first analog output signal at said time t.sub.1 and the voltage level of said first analog output signal at said time t.sub.2 ;
- means for multiplying said second signal and said third signal to produce a fourth signal;
- and
- means for algebraically summing said fourth signal and said first signal to produce a fifth signal representative of a corrected integration of said first analog output signal.
A method for integrating a first analog output signal having a varying voltage in time comprising the steps of:
- integrating said first analog output signal over a period beginning at time t.sub.1 and ending at time t.sub.2 and establishing a first signal representative of the results of the integration of said first analog output signal;
- correcting said first signal if the voltage level of said first analog output signal at said time t.sub.1 does not equal the voltage level of said first analog output signal at said time t.sub.2, said step of correcting said first signal comprising:
- establishing a second signal representative of the time period t.sub.2 -t.sub.1 ;
- establishing a third signal representative of the difference between the voltage level of said first analog output signal at said time t.sub.1 and the voltage level of said first analog output signal at said time t.sub.2 ;
- multiplying said second signal and said third signal to produce a fourth signal;
- and
- algebraically summing said fourth signal and said first signal to produce a fifth signal representative of a corrected integration of said first analog output signal.
Dependencies are inferred from the claim text.