Method and apparatus for obtaining accurate readout of breath testers

Claim 1

In a breath tester of the type that includes a detector which produces time varying d.c. output electrical signals having a peak amplitude representative of gaseous content, which signals vary during a period of detecting, the improvement comprising: memory means for producing and holding a peak signal, coupled to the output of said detector and responsive to the detector''s peak output signal; variable signal means (331) for producing selectively variable output signals; readout means (233) coupled to the variable signal means for giving a readout proportional to the signal output of said variable signal means; and an indicator (227) coupled to receive and compare the output signals of said memory means and said variable signal means for indicating when those signals reach a predetermined relationship; whereby said variable signal means may be adjusted to reach said predetermined relationship and an accurate readout of the detected gaseous content may be obtained and stored on said readout means.

Claim 5

The method of obtaining an accurate inebriate breath testing system of the type employing an equivalent blood alcohol (EBA) detector from which a time varying d.c. electrical output signal is produced, which signal''s peak value is a function of EBA, using a peak signal memory, a selectively variable signal source, and means for indicating the output of the variable signal source, comprising the steps of: a. coupling the detector''s output signal to the peak signal memory for a given time period, and b. thereafter, adjusting the potential provided by the variable signal source to achieve a predetermined relationship relative to the output of the peak signal memory; so that the output indicating means will indicate the blood alcohol level.

Claim 6

The method of obtaining an accurate inebriate breath testing system of the type employing an equivalent blood alcohol (EBA) detector from which a time varying d.c. electrical output signal is produced, which signal''s peak value is a function of EBA, using a peak signal memory, a selectively variable signal source, and means for indicating the output of the variable signal source, comprising the steps of: a. coupling the detector''s output signal to the peak signal memory for a given time period, and b. thereafter, adjusting the potential provided by the variable signal source to achieve a predetermined relationship relative to the output of the peak signal memory; so that the output indicating means will indicate the blood alcohol level.

Claim 8

The method of obtaining an accurate record of a subject''s breath in terms of alcohol blood equivalents, employing a time varying d.c. output detector whose peak output is indicative thereof, a d.c. peak signal holding and reproducing memory circuits, a potentiometer coupled to a fixed voltage source, a turns counter calibrated in alcohol blood equivalent units coupled to the potentiometer for giving an indication of its tap''s setting, and a null indicator, comprising the steps of: a. causing the subject''s breath to enter the detector; b. coupling the detector''s output to the peak memory circuit for a selected period; c. after that period, coupling the memory circuit''s output and the potentiometer''s output to the null indicator; d. changing the potentiometer output until the null indicator indicates that it is equal to the memory circuit''s output; and e. recording the turns counter''s indication.

Claim 9

The method of obtaining an accurate record of a subject''s breath in terms of alcohol blood equivalents, employing a time varying d.c. output detector whose peak output is indicative thereof, a d.c. peak signal holding and reproducing memory circuits, a potentiometer coupled to a fixed voltage source, a turns counter calibrated in alcohol blood equivalent units coupled to the potentiometer for giving an indication of its tap''s setting, and a null indicator, comprising the steps of: a. causing the subject''s breath to enter the detector; b. coupling the detector''s output to the peak memory circuit for a selected period; c. after that period, coupling the memory circuit''s output and the potentiometer''s output to the null indicator; d. changing the potentiometer output until the null indicator indicates that it is equal to the memory circuit''s output; and e. recording the turns counter''s indication.