AS1545
Datasheet - Terminology
Total Harmonic Distortion (THD)
The Total Harmonic Distortion is the ratio between the RMS value of the fundamental (input signal) to the RMS value of
the first five harmonics.
V22 + V32 + V42 + V52 + V62
THD(dBc) = 20*log -----------------------------------------------------------------------
V1
Where:
V1 is the RMS power of the input frequency (fundamental)
V2 to V6 are the RMS values of the first five harmonics
Spurious Free Dynamic Range (SFDR)
The Spurious Free Dynamic Range defines the ratio between the RMS value of the fundamental to the RMS value of
the largest peak off all spectral components below one-half of the sampling frequency, including harmonics but
excluding DC.
Channel to Channel Isolation
The Channel to Channel Isolation (Crosstalk) defines the coupling of energy from one channel into the other channel in
the ADC. It is measured by applying a 40kHz sine wave to all unselected channels and the attenuation to a 50kHz
input sine wave is determined.
Intermodulation Distortion (IMD)
The Intermodulation Distortion measures the creations of additional spectral components that are caused by
nonlinearities when applying a two tone sine wave on the input of the ADC. IMD is the ration of the RMS power in
either the second or the third intermodulation products to the sum of both input frequencies.
2nd order intermodulation products (IM2): f1+f2, f2-f1
3rd order intermodulation products (IM3): 2*f1-f2, 2*f2-f1, 2*f1+f2, 2*f2+f1
Full Power Bandwidth / Full Linear Bandwidth
The Full Power Bandwidth defines the frequency at which the reconstructed input signal amplitude drops 3dB from the
actual amplitude of the input signal, when applying a full scale signal.
The Full Linear Bandwidth defines the frequency at which the reconstructed input signal amplitude drops 0.1dB from
the actual amplitude of the input signal, when applying a full scale signal.
www.austriamicrosystems.com
Revision 1.01
17 - 34
AMSCO [ AMS(艾迈斯) ]
