CS4227 Datasheet, PDF (33/36 Pages) Cirrus Logic – Six Channel, 20-Bit Codec

CS4227
4. 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 effect the measurement. This measurement technique has been accepted by the Audio
Engineering Society, AES17-1991, and the Electronic Industries Association of Japan, EIAJ CP-307.
Total Harmonic Distortion + Noise
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 AES 17-1991 Annex A.
Idle Channel Noise / Signal-to-Noise-Ratio
The ratio of the rms analog output level with 1kHz 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
decibels. This specification has been standardized by the Audio Engineering Society, AES17-1991, and
referred 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 input grounded. For
the DAC's, the deviation of the output from zero (relative to CMOUT) with mid-scale input code. Units
are in volts.
DS281PP2
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