IEC 60050 - International Electrotechnical Vocabulary


IEVref:	801-32-62		ID:
Language:	en		Status: Standard

Term:	source level
Synonym1:	sonar source level
Synonym2:	SL [Admitted]
Synonym3:
Symbol:	L_S
Definition:	sum of sound pressure level $L_{p} (x)$ , at position $x$ , and propagation loss from the source position to the receiver position, $N_{PL} = (x - x_{0})$ , where $x_{0}$ is the source position Note 1 to entry: In equation form, $L_{S} = L_{p} + N_{PL}$ . Note 2 to entry: Source level is only defined for an equivalent monopole (point) source, where the sonar is treated as a point source of sound. For this treatment to be valid, the measurement position, $x$ , shall be in the acoustic far field of the sonar source. Note 3 to entry: This definition of source level is consistent with that of ISO 18405, which is more generally applicable, as it is valid for a finite source. Note 4 to entry: When sound pressure level is defined as ten times the logarithm of the mean square pressure, the reference value for source level is 1 µPa²m² and the reference value for propagation loss is 1 m². Note 5 to entry: When sound pressure level is defined as twenty times the logarithm of the root-mean-square pressure, the reference value for source level is 1 µPa·m and the reference value for propagation loss is 1 m. Note 6 to entry: This note applies to the French language only.
Publication date:	2021-02
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Lp(x)MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqipu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGacaGaaiaabmqaamaabaabaaGcbaGaamitamaaBa aaleaacaWGWbaabeaakmaabmaabaGaamiEaaGaayjkaiaawMcaaaaa @3A59@xMathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqipu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGacaGaaiaabmqaamaabaabaaGcbaGaamiEaaaa@36D4@propagation lossNPL=(x−x0)MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqipu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGacaGaaiaabmqaamaabaabaaGcbaGaamOtamaaBa aaleaacaqGqbGaaeitaaqabaGccqGH9aqpdaqadaqaaiaadIhacqGH sislcaWG4bWaaSbaaSqaaiaaicdaaeqaaaGccaGLOaGaayzkaaaaaa@3EE8@x0MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqipu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGacaGaaiaabmqaamaabaabaaGcbaGaamiEamaaBa aaleaacaaIWaaabeaaaaa@37BA@Note 1 to entry: In equation form,

L_{S} = L_{p} + N_{PL}

.Note 2 to entry: Source level is only defined for an equivalent monopole (point) source, where the sonar is treated as a point source of sound. For this treatment to be valid, the measurement position,

x

, shall be in the acoustic far field of the sonar source.Note 3 to entry: This definition of source level is consistent with that of ISO 18405, which is more generally applicable, as it is valid for a finite source.Note 4 to entry: When sound pressure level is defined as ten times the logarithm of the mean square pressure, the reference value for source level is 1 µPa²m² and the reference value for propagation loss is 1 m².Note 5 to entry: When sound pressure level is defined as twenty times the logarithm of the root-mean-square pressure, the reference value for source level is 1 µPa·m and the reference value for propagation loss is 1 m.Note 6 to entry: This note applies to the French language only.