Xaoc Devices JENA Operator's Manual page 5

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Input CV
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Output CV
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clOcKinG and synchrOnOus/
asynchrOnOus OPeratiOn
The incoming data is delivered to Jena
through the Leibniz interface which transmits
all bits alongside the data clock. For example,
if you connect Jena to Drezno, samples will be
transmitted at a rate of nearly 2MHz unless
you patch an external clock signal to the adc
clk jack in Drezno. Jena's processed data may
be delivered to its output synchronously with
the incoming clock period, or it can be re-sam-
pled with the internal (also very fast) clock.
External/internal clocking is selected using
the setup mode. Setting the internal clock may
be advantageous when your data is clocked
slowly at the source (e.g. Drezno) but you still
want to apply a quick modulation to the wave.
Regardless of the currently selected clock
source, processing in Jena occurs within
two distinctive regimes. With asynchronous
operation, every new input digital value is
translated almost instantly (there is a sev-
eral microsecond delay due to processing) to
the sample value of the current shape. This
type of operation is best suited for wavesh-
aping applications (e.g. folding and warping
CV signals), as shown in fig. 3.
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Output CV
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5
Input CV
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fig. 3
various input cv signals transformed with the same
nonlinear shaping function
However, if you want to use Jena as an oscil-
lator you may prefer the input data to scan
the entire phase range of the waveform to
avoid the cycle being abruptly cut off before
its end (fig. 4). Note also that the returning
edge of your ramp scans the waveshape and
may produce an audible glitch when not per-
fectly sharp. The synchronous regime does
not require the input data to scan the entire
range of 0...255 accurately and with a sharp
returning edge. Instead, it uses an algorithm
to analyze the incoming data and determine
its current frequency and phase. It then in-
ternally generates a perfect virtual ramp
that scans the function cycle in accordance
with the input cycles. This enables easy gen-
eration of undistorted waveforms from the
bank, like in a classic wavetable oscillator,
but with the addition of through-zero phase
modulation from the phase jack. The dis-
advantage of the synchronous operation is
that there is a little lag after each abrupt
pitch change when the new period length
is computed. Also, modulating the shape of
the driving wave may confuse the algorithm
and cause pitch artifacts. To select between