Abstract: Through enhanced designing or adding 3^rdparty module,the accuracy rate and reliability rate of signal detection can be improved．One algorithms concatenation theory for enhancing signal detection is provided within research of the quantitative relation between positive alarming rate(PAR) and false alarming ratio(FAR)．The policy can guide developers to design post-processing or pre-processing algorithm which is connected with already-known algorithms in tandem．Two usage samples on QRS complex detection in ECG digital processing and Tone Detection in FSK are discussed with application of this policy．Three highlights in this research:1) Consideration of the quantitative relation between PAR and FAR disclosing the indirect contradictory hidden in PAR and FAR(Theorem 1)；2) Putting forward one sufficient condition to solve the contradictory(Theorem 2) --the theory of enhancing signal detection；3) Two application cases being attached to verify how to apply this theory.

Key words: Positive alarming rate(PAR),False alarming ratio(FAR),QRS complex detection,FSK tone detection