CS4222
6. PARAMETER DEFINITIONS
Dynamic Range
The ratio of the full scale rms value of the signal to the rms sum of all other spectral components over the
specified bandwidth. Dynamic range is a signal-to-noise measurement over the specified bandwidth
made with a -60 dBFS signal. 60 dB is then added to the resulting measurement to refer the measurement
to full scale. This technique ensures that the distortion components are below the noise level and do not
affect the measurement. This measurement technique has been accepted by the Audio Engineering So-
ciety, AES17-1991, and the Electronic Industries Association of Japan, EIAJ CP-307.
Total Harmonic Distortion + Noise (THD+N)
The ratio of the rms value of the signal to the rms sum of all other spectral components over the specified
bandwidth (typically 20 Hz to 20 kHz), including distortion components. Expressed in decibels. ADCs are
measured at -1 dBFS as suggested in AES17-1991 Annex A and DACs are measured at 0 dBFS.
Idle Channel Noise / Signal-to-Noise-Ratio
The ratio of the rms analog output level with 1 kHz full scale digital input to the rms analog output level
with all zeros into the digital input. Measured A-weighted over a 10 Hz to 20 kHz bandwidth. Units in deci-
bels. This specification has been standardized by the Audio Engineering Society, AES17-1991, and re-
ferred to as Idle Channel Noise. This specification has also been standardized by the Electronic Industries
Association of Japan, EIAJ CP-307, and referred to as Signal-to-Noise-Ratio.
Total Harmonic Distortion (THD)
THD is the ratio of the test signal amplitude to the rms sum of all the in-band harmonics of the test signal.
Units in decibels.
Interchannel Isolation
A measure of crosstalk between channels. Measured for each channel at the converter's output with no
signal to the input under test and a full-scale signal applied to the other channel. Units in decibels.
Frequency Response
A measure of the amplitude response variation from 20 Hz to 20 kHz relative to the amplitude response
at 1 kHz. Units in decibels.
Interchannel Gain Mismatch
For the ADCs, the difference in input voltage that generates the full scale code for each channel. For the
DACs, the difference in output voltages for each channel with a full scale digital input. Units are in decibels.
Gain Error
The deviation from the nominal full scale output for a full scale input.
Gain Drift
The change in gain value with temperature. Units in ppm/°C.
Offset Error
For the ADCs, the deviation in LSB's of the output from mid-scale with the selected inputs tied to a com-
mon potential. For the DAC's, the differential output voltage with mid-scale input code. Units are in volts.
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DS236F1
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