CS4297
CrystalClear™ SoundFusion™ Audio Codec ’97
range of 20 Hz to 20 kHz. This performance plots
used an “A”-weighted filter applied on the output
PERFORMANCE PLOTS
Figures 11 through 26 show the overall Frequency
Response, the THD+N over frequency, and the DR
over frequency of the ADCs, the DACs, the analog
mixer (Line In to Line Out) and the microphone in-
puts. Crosstalk plots and the noise floor FFT plots
of the DACs, the analog mixer and the muted noise
Figures 24, 25, and 26: The noise floor plots were
generated by running a 16K-point FFT on the
LINE_OUT output with no input signal applied.
The Muted Noise Floor plot was taken with the
master mute bit ‘set’ (bit D15, register 0x02h).
floor of the CS4297 are also included. All plots These performance plots used an “A”-weighted fil-
were taken on a CRD4297-1 with a CS4297-KQ ter applied on the output
Codec.
All audio performance plots used unity gain set-
Figures 11, 14, 17, and 20: The Frequency Re- tings on the analog volume controls. Additionally,
sponse plots were taken using a -20 dB FS input the microphone input plots were taken with the +20
signal swept over the frequency range of 20 Hz to
20 kHz and normalized to 0 dB at 1 kHz.
dB gain stage enabled (bit D6, register 0x0Eh).
The ADC plots used the A-D signal path. The DAC
plots used the D-A signal path. The mixer and the
microphone plots used the A-A signal path.
Figures 12, 15, 18, and 21: The THD+N plots were
taken using a -3 dB FS input signal swept over the
frequency range of 20 Hz to 20 kHz. These perfor-
mance plots used an “A”-weighted filter applied on
the output with the exception of the ADC THD+N
plot.
Figures 13, 16, 19, and 22: The Dynamic Range
plots were taken using a -50 dB FS input signal
swept over the frequency range of 20 Hz to 20 kHz.
These performance plots used an “A”-weighted fil-
ter applied on the output with the exception of the
ADC Dynamic Range plot.
Figure 23: The crosstalk plot was generated using a
0 dB FS input signal on one channel of the
LINE_IN input and measuring the magnitude of
the other output channel swept over the frequency
34
DS242F5
CIRRUS [ CIRRUS LOGIC ]
