SINAD
SINAD ( s ignal-to- i nterference ratio Including n oise a nd d istortion , as SND / ND hereinafter) is a measure of the transmission quality: higher SINAD value corresponds to a higher transmission quality.
SINAD describes the ratio of the total signal power , consisting of the useful signal , noise and distortion , to the sum of the interference signal , consisting of noise and distortion, of a low-frequency signal (e.g. at the output of a radio receiver ):
This ratio is usually expressed in the logarithmic auxiliary unit Bel .
In principle, the SINAD value cannot fall below 0 dB. If there is no useful signal, the numerator and denominator in the above equation are equal:
The SINAD measurement takes place e.g. B. Use in radio communication ( AM and FM ). With their help, further parameters of transmitters and receivers are measured, e.g. As the receiver sensitivity , the image frequency resistance, the intermodulation strength, etc.
To do this, however, the boundary conditions of the SINAD measurement must be specified more precisely than the above simple equation suggests:
- Frequency of the useful signal: 1000 Hz , 1020 Hz or another value.
- with or without psophometric evaluation (simulation of the frequency response of hearing ) z. B. according to A-rating or ITU-T O.41.
- Voltage measurement: effective value or quasi-peak value
SINAD values measured with different boundary conditions are therefore not comparable with one another.
See also
literature
- Stefan Weinzierl (Ed.): Handbook of audio technology. Springer, Berlin et al. 2008, ISBN 978-3-540-34300-4 .
- ETSI EN 300 086-1 V1.3.1 (2008-09), Electromagnetic compatibility and Radio spectrum Matters (ERM); Land mobile service; Radio equipment with an internal or external RF connector intended primarily for analogue speech; Part 1: Technical characteristics and methods of measurement
- TIA-603-C, Land Mobile FM or PM Communications Equipment Measurement and Performance Standards, Telecommunications Industry Association, December 2004
- ITU-T O.41, Psophometer for use on telephone-type circuits, International Telecommunication Union, Telecommunication Standardization Sector, 1994
- Curt Rint (Ed.): Handbook for high frequency and electrical technicians. 13th revised edition. Volume 2. Hüthig and Pflaum, Heidelberg et al. 1981, ISBN 3-7785-0699-4 .