T+A PDP 3000 HV, User Manual

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PDP 3000 HV and PCM
The PCM process makes extremely high-resolution sampling values available:
up to 32 bits. However, the sampling rate of PCM is significantly lower than that
of DSD, and the spacing in terms of time between the sampling values is
greater.
This means that it is extremely important with PCM to employ maximum
possible precision when converting the high resolution into analogue signals.
Here at

our answer was to develop quadruple D/A converters which
provide a four-fold improvement in accuracy over conventional converters. A
further very important aspect of PCM reproduction is to reconstruct the curve of
the original analogue signal between the sampling points with great accuracy,
since these points are much more widely spaced in comparison with DSD. To
this end the
PDP 3000 HV employs a polynomial interpolation process (Bezier-
Spline interpolation) developed in-house at

, which in mathematical terms
delivers the smoothest curve for a given number of reference points (sampling
points). The output signal generated by Bezier interpolation exhibits a very
“natural” shape, devoid of the digital artefacts - such as pre- and post-
oscillation - which are usually produced by the standard oversampling process.
More detailed information on this can be found in the chapter
“Technical
description, oversampling / up-sampling
”
And one final comment: If you intend to carry out your own tests to decide
whether DSD or PCM is the superior format, please be sure to compare
recordings with comparable information density
– i.e. DSD64 with PCM96/24,
DSD128 with PCM 192 and DSD256 with PCM384 !