dCS 904 User Manual

Manual for Software Version 1.5x and 1.36

dCS Ltd

June 2000

 

 

Filter

Comments

SQNR

SQNR

E2 specE3 spec

 

 

 

(20 kHz,

(F weighted

(dB)

(dB)

 

 

 

dB)

dB)

 

 

1

High

SQNR,

126.14

-136.56

-25.98

-28.96

 

high stability

 

 

 

 

2

High SQNR

127.23

-138.76

-25.85

-28.95

3

High

SQNR,

124.66

-134.38

-27.32

-30.49

 

very

high

 

 

 

 

 

stability

 

 

 

 

 

4

Extremely high

122.07

-129.91

-25.54

-29.53

 

stability

 

 

 

 

 

5

Reduced 100k

122.27

-130.14

-27.13

-31.99

 

noise

 

 

 

 

 

6

Single

 

110.78

-151.02

-25.19

-23.55

 

complex zero

 

 

 

 

7

Real zeros

101.5

-132.41

-25.29

-27.04

 

SACD Spec

 

 

-20.00

-28.00

 

 

 

 

 

 

 

Table 4 – DSD Filter Performance

DSD Full Scale

The SACD standard sets 0 dB0 for programme material 6 dB below the peak to peak level one might expect a full scale sinewave to occupy. This ensures that artefacts that begin to occur at the limits of the DSD frequency range stay well away from the audio band, and is shown in Figure 11, on page 34. The dCS 904 complies with this standard. If the unit is set up for full scale PCM, and then switched to a DSD format, the levels will be correctly set to meet SACD standards.

DSD Mute

A DSD mute is unlike a PCM mute (which is 00000….), because with only two

levels, there is not a single value that sets the output in the middle of the range. In all DSD formats except P3D, the dCS 904 outputs 010101010101…. as a

DSD mute. For P3D it outputs 01101001 as a P3D DSD mute.

DSD Overload Behaviour

DSD is more benign than PCM under overload conditions. In the overload region, the performance gradually and gracefully degrades. The size of this region depends on the modulator used, but in general, a modulator with a higher stability will allow a larger overload region (see Table 3 – DSD Filter Summary). The overload region may be several dB. In the dCS 904, the signal level is digitally clamped about 1.5 dB above SACD 0dB level.

dCS modulators recover from overload rapidly

DSD Electrical and Data Structures

Electrically, for the SDIF-2 and SDIF-3 outputs, TTL levels are used. There is no framing or block structure, and each channel uses one BNC connector. The clock (word or bit clock) uses the third connector. See Figure 33 on page 52.

Manual part no: DOC135904 iss 2B2

Page 33

135904ma2b2.pdf file available from website

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