dCS 974 User Manual

Manual for Software Version 1.0x

dCS Ltd

May 2001

dCS 974 PERFORMANCE CURVES

 

0.5%

 

 

 

 

0.4%

 

Bin

 

 

OccupiesDitherTime

0.3%

 

 

 

Fraction of

0.2%

 

 

 

 

0.1%

 

 

0.0%

 

 

-384

The graphs on the following pages show key performances of the dCS 974.27

•Dither PDFs, showing how the dither types are effectively ideal, including noise shaped triangular dither

•FFTs of the dither signals used (excludes truncation, or Q, noise)

•Raw data for small signal truncated (± 4 lsbs) sinewave, showing source waveform, no dither, and all dither types. Shows absence of DC offset, and behaviour of the various dithers

•FFTs of truncated small signal (-90 dB0 sine), showing no truncation, truncation without dither, and the effect of dithers.

•FFTs of truncated small signal (-90 dB0 sine), with noise shaping, with and without added dithers.

•DSD spot Q noise for filter options

•DSD integrated Q noise for filter options

•DSD F weighted Q noise for filter options

•DSD 0 dB0 (full scale) signal

•48 kS/s to 44.1 kS/s conversion, Filter responses

•96 kS/s to 44.1 kS/s conversion, Filter responses

•Noise shaping curves for 32 kS/s

•Noise shaping curves for 44.1 kS/s

•Noise shaping curves for 48 kS/s

•Noise shaping curves for 88.2 kS/s

•Noise shaping curves for 96 kS/s

•Noise Shaper noise and weighted noise vs shaper order

Histograms of Dither Types, before Truncation

dCS 972 SW v1.54

2 million data points

Word length reduced by 8 bits

Top Hat

Triangular

Noise Shaped Triangular

-256

-128

0

128

256

384

 

 

Code (lsbs)

 

 

 

Figure 31 – Dither PDFs

27Note that many aspects of the dCS 974 are identical to those of the dCS 972.

Manual part no: DOC1241121A1

Page 94

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