Resonessence INVICTA User Manual page 16

6. Continue to choose "Next" when
appropriate, and the installation
will complete after a short while:
7. At this point the driver software is
in place, ready to be found by
Windows. The next time Windows
sees the INVICTA USB Audio 2.0
connected it will install the
Thesycon specific INVICTA driver.
To use the newly installed driver,
select the Resonessence INVICTA in the
Sounds "Manage Devices" control panel.
Windows thereafter will direct digital
audio over the USB Audio 2.0 connection
with all the advanced 2.0 features (such
as 192ks/s data rate) available.
Appendix B
Up-sampling Filters in the
INVICTA rev 3.0 Software
• The internal Fast Roll-off filter pre-installed
in the Sabre DAC.
On the OLED display panel this appears as
"Sabre Fast Roll-Off"
This is a 'classic' FIR filter with symmetrical
coefficients, hence it is linear phase and non-
dispersive. It achieves excellent suppression of
-115db, and so has to have a relatively large
group delay of 35 samples. That means, that for
a CD at 44.1Khz the group delay is about 800uS.
(less for higher sample rates). This filter exhibits
pre-ringing, but achieves perfection in rejection:
no sample rate artifacts above 22.05Khz are
present in the output.
• The internal Slow Roll-off filter pre-installed
in the Sabre DAC.
On the OLED display panel this appears as
"Sabre Slow Roll-Off"
This filter is designed to reduce the group delay
present in the Fast Roll-off filter. It is a
symmetrical impulse response (i.e. it has
symmetrical coefficients), it is linear phase and
non-dispersive. It achieves good rejection but
the rejection begins slowly, 24Khz or so is
present in the output if the music content has
signals near 20khz, but signals higher than that
are suppressed. The group delay however is
much less, being only 6.25 samples or 140uS at
44.1Khz. This filter also exhibits pre-ringing.
• Resonessence designed, Minimum Phase, IIR
Filter
On the OLED display panel this appears as
"Minimum Phase IIR"
This filter is designed from an analog filter
prototype and exhibits no pre-ringing at all. To
achieve this, it has to compromise the steepness
of the filter; it corresponds to a fourth order
analog filter. This is a dispersive non-linear
phase filter, but the dispersion has been
optimized to the absolute minimum consistent
with no pre-ringing.