DCS Computer Hardware dCS 974 User Manual
dCS 974 User Manual
Manual for Software Version 1.0x
dCS Ltd
May 2001
Manual part no: DOC1241121A1
Page 96
Document No: OS-MA-A0124-112.1A1
Contact
dCS
on + 44 1799 531 999
email to: more@dcsltd.co.uk
(inside the UK replace + 44 with 0)
web site: www.dcsltd.co.uk
Spectra of -90dB 24 bit sinewave truncated to 16 bits with dither options
dCS 972 SW v1.54
-160
-140
-120
-100
-80
-60
0
2
4
6
8
10
12
14
16
18
20
22
Frequency (kHz)
A
m
pl
itu
de (
dB
)
24 bit source data
16 bit truncation, no dither
16 bit truncation, Top Hat dither
16 bit truncation, Triangular dither
16 bit truncation, Noise Shaped Triangular dither
44.1 kS/s sampling, -90 dB 1.44 kHz
input, 1024 point FFTs, H6 Window
Figure 34 – Truncated small signal FFT, with and without dither
Noise Shaper and Noise Shaper with Dither Performance
dCS 972 SW v1.54
-160
-140
-120
-100
-80
-60
0
2
4
6
8
10
12
14
16
18
20
22
Frequency (kHz)
A
m
pl
itude,
R
eal
D
at
a
(dB
)
16 bit truncation, 10th order noise shaping, no dither
16 bit truncation, 10th order noise shaping, Top Hat dither
16 bit truncation, 10th order noise shaping, Triangular dither
16 bit truncation, 10th order noise shaping, Noise Shaped Triangular dither
44.1 kS/s sampling, 1024 point FFTs, H6 window, -90 dB 1.44 kHz input,
10th Order Noise Shaping
Figure 35 – Truncated small signal FFT, showing noise shaping with and without dither