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KRELL DIGITAL SBP-64X DESIGN FEATURES
Software Based Processing requires a perfect blend of exacting, multifaceted
technologies, from high tech digital innovation to an ultimate refinement of analog
circuit design.
On the next two pages, we will briefly point out our methods of addressing these
requirements in the Krell Digital SBP-64X.
INPUT
The SBP-64X will accommodate both Coaxial and Fiber Optical input to insure
compatibility with any digital source with digital outputs.
PROCESSING
The "Waveform Replicator"
The KDI SBP-64X uses proprietary "Waveform Replicator" software which
enables our four Motorola processors to perform polynomial computations for cal-
culating the 63 additional data points to fill our 64 times oversampling requirements.
The Motorola DSP-56001
We have chosen the Motorola DSP-56001 for two reasons which make this pro-
cessor clearly superior to any other for a similar application; Dynamic Headroom,
and Precision.
Dynamic Headroom
The DSP-56001 uses a 24 bit data path which relates to a 48 dB increase in
dynamic headroom over components using different processors.
Precision
Of critical importance to any processor is the size of its accumulator, for this
limits the size of the computational coefficients it can utilize. If the coefficient is to
9
large it will overflow the processor, forcing it to scale the computation. In audio
processing this is especially damaging because the processors perform multiple com-
putations based on one data sample, so each repetitive computation is based on a
scaled figure which compounds the error on each computation. Thus, the size of the
accumulator limits the potential precision of a processor’s calculations.
The Motorola DSP-56001 gives your KDI SBP-64X substantially higher precision
than other components based on different processors.
28 MHZ clock speed
The SBP-64X is run at over 28,000,000 cycles per second. This high speed,
coupled with the DSP-56001’s ability to perform multiple operations during a single
instruction cycle gives the SBP-64X greater computing power than other, even higher
speed processors.
DIGITAL TO ANALOG CONVERSION
THE DACs
The SBP-64X utilizes twin Burr Brown PCM-64 18 bit DACs for high speed and
superb accuracy.
Parallel Data Into The DACs
Unlike the majority of other processors in the industry, the SBP-64X runs
parallel data through the DSP’s, and into the DACs. By using these 18 bit DACs, in
parallel, we are able to maintain the incredible speed required for 64x oversampling
without multiplexing, and tl]~n, summing the data.
NO "BRICK WALL" FILTERING
The exacting nature of our digital information and the extraordinary technique
by which our DACs perform their conversions enable us to avoid any type of steep
slope cut off (brick wall) filtering in the SBP-64X. Therefore, you experience the
benefit of absolute purity in the signal without any of the undesirable effects of those
filters.
DISCRETE CURRENT TO VOLTAGE
Current to Voltage (1iV) conversion, is performed in the analog domain, directly
after D/A. In most processors this occurs either in the DAC itself or in an external
integrated circuit op-amp. At Krell Digital, we feel that these methods are unaccept-
able. Therefore, we have engineered a 100% discrete Current to Voltage stage for