SINAD

SINAD (signal -to -interference ratio including noise and distortion, even SND / ND called ) is a measure of the transmission quality: a higher SINAD value corresponds to a higher transmission quality.

SINAD is the ratio of the Gesamtsignaleistung consisting of useful signal, noise and distortion, to the sum of the interference signal consisting of noise and distortion, a low-frequency signal (eg, the output of a radio receiver ):

Most of this is expressed in the logarithmic auxiliary unit Bel.

Due to the principle can not fall below 0 dB of the SINAD value. Namely, when no useful signal is present, the numerator and denominator in the above equation are equal:

The SINAD measurement is used, for example, use the radio (AM and FM). With the help of other parameters of transmitters and receivers can be measured, for example, the receiver sensitivity, the image frequency resistance, the intermodulation distortion, etc.

To this end, however, the boundary conditions of the SINAD measurement must be specified more precisely than is suggested above simple equation:

• Frequency of the useful signal: 1000 Hz, 1020 Hz, or a different value.
• With or without psophometric Rating ( replica of the frequency response of the hearing), for example, after A-weighting or ITU- T O.41.
• Voltage measurement: RMS or quasi-peak

Measured with different boundary conditions SINAD values ​​are not comparable.