Quantitative Evaluation of SRS Similarity for Aerospace Testing Applications

Table 1

Summary of database SRS retrieval metrics.

Metric	Formula	Best SRS similarity	Worst SRS similarity	Remark
DIFF (f)		0 dB	Tends to positive infinity	(i) Pointwise calculation
				(ii) May show attenuation at specific frequencies
MAD		0	Tends to positive infinity	(i) Single scalar representation of similarity
				(ii) Suitable for repeatability calculations (for minimal differences)
ASR		1	The SRS profile may be dissimilar for all values	(i) It ignores lower frequencies (<1 kHz)
				(ii) Suitable for evaluating reproducibility (making the same measurement with different equipment or different personnel)
		1		(i) May show overall attenuation
		1		(i) Considers only the peak acceleration value
				(ii) May demonstrate attenuation for applications where the peak acceleration is the critical parameter
RMSE		0 dB	Tends to positive infinity	(i) Single scalar representation
				(ii) Cannot distinguish the sign of the positive and negative deviations
		0	1	(i)Single scalar representation
				(ii) Preferentially selects positive deviation