Device for the monitoring of peak values of a nonperiodic phenomenon with a low recurrence rate

An analog discharge signal monitor for monitoring a voltage signal from a power battery, said signal including a slow monotonous variation having peak values indicating no load periods of said battery, said peak values interspersed with non-significant portions of the signal during load periods of said battery, said non-significant portions having a variable duration, said duration being small with respect to the average time of discharge, said monitor comprising:

• comparator means for comparing two inputs and for providing an output indicative of said comparison, one of said inputs being connected to terminals of said battery to receive a signal indicating the voltage produced by said battery;
• means for rectifying said comparator means output, said rectifying means connected in series with said comparator means output, said rectifying means having an output;
• parallel RC circuit means having a resistance, said RC circuit means coupled in parallel with the output of said rectifying means;
• and
• high input impedance means having an input and an output, said impedance means input connected in parallel with said parallel RC circuit means, said impedance means output providing discharge information, said impedance means having said output coupled back to said other of said comparator inputs wherein said parallel RC circuit means has a time constant RC which substantially satisfies the condition RC=t V/yxU where:
• U is the initial peak value of the voltage of said battery;
• V is the voltage across the RC circuit means with said peak value U applied to the monitor;
• x is the predetermined fractional decrease in the voltage U permitted after which said battery is determined to be discharged;
• t is an estimated value of the time duration of intervals between no load conditions of said battery wherein t is significantly shorter than the actual discharge time of said battery;
• and
• y is the permissible fractional error between the actual voltage decrease which takes place in said battery during time t and the decrease in voltage indicated by the output of said high input impedance means during time t.