PCM1600 Burr-Brown Corporation, PCM1600 Datasheet - Page 27

• Manufacturer Part Number: PCM1600
• Description: 24-Bit/ 96kHz Sampling/ 6-Channel/ Enhanced Multi-Level/ Delta-Sigma DIGITAL-TO-ANALOG CONVERTER
• Manufacturer: Burr-Brown Corporation

FIGURE 20. Quantization Noise Spectrum.
THEORY OF OPERATION
The delta-sigma section of PCM1600 is based on a 8-level
amplitude quantizer and a 4th-order noise shaper. This
section converts the oversampled input data to 8-level delta-
sigma format.
A block diagram of the 8-level delta-sigma modulator is
shown in Figure 19. This 8-level delta-sigma modulator has
the advantage of stability and clock jitter sensitivity over the
typical one-bit (2 level) delta-sigma modulator.
The combined oversampling rate of the delta-sigma modu-
lator and the internal 8x interpolation filter is 64f
system clock combinations (256/384/512/768f
The theoretical quantization noise performance of the
8-level delta-sigma modulator is shown in Figure 20. The
enhanced multi-level delta-sigma architecture also has ad-
vantages for input clock jitter sensitivity due to the multi-
level quantizer, with the simulated jitter sensitivity shown in
Figure 21.
FIGURE 19. Eight-Level Delta-Sigma Modulator.
–100
–120
–140
–160
–180
–20
–40
–60
–80
0
0
8f
S
1
+
2
Z
–1
3
Frequency (f
4
S
)
5
+
6
Z
S
–1
).
7
S
for all
8
8-Level Quantizer
27
+
+
+
KEY PERFORMANCE PARAM-
ETERS AND MEASUREMENT
This section provides information on how to measure key
dynamic performance parameters for the PCM1600 and
PCM1601. In all cases, an Audio Precision System Two
Cascade or equivalent audio measurement system is utilized
to perform the testing.
TOTAL HARMONIC DISTORTION + NOISE
Total Harmonic Distortion + Noise (THD+N) is a significant
figure of merit for audio D/A converters, since it takes into
account both harmonic distortion and all noise sources
within a specified measurement bandwidth. The true rms
value of the distortion and noise is referred to as THD+N.
For the PCM1600 and PCM1601 D/A converters, THD+N is
measured with a full scale, 1kHz digital sine wave as the test
stimulus at the input of the DAC. The digital generator is set
FIGURE 21. Jitter Sensitivity.
–
64f
S
125
120
115
110
105
100
95
90
85
80
Z
–1
0
PCM1600, PCM1601
100
+
200
CLOCK JITTER
Z
Jitter (ps)
–1
300
400
500
600
®