Mungo Enterprises State Zero User manual

State Zero
Reference Manual
Copyright 2010, Mungo Enterprises

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Contents
Connections 4
Power 6
Display 6
Audio 6
Midi 6
Patchfield 6
Module Reference 8
Introduction 9
Oscilloscope 10
Master 12
Oscillator 14
Low Frequency Oscillator 16
Envelope 18
Filter 20
Amplifier 20
Comparator 22
Sample and Hold 22
Slew Rate Limiter 24
Curve and Quantize 24
Mixer 26
Sources 28
Tempo 30
Audio 30
Memory 32
Voice 32
Synthesis Techniques 34
Normalling 35
Portamento 35
Legato 36
Fingered Portamento 36
Filter Resonance 37
Envelope Curves 37
Envelope Variations 38
Envelope Hold 38
Service Notes 40
Shipping 41
Wood Care 41
Routine Maintenance 41
Case Access 42
Part Replacement 42
Repairs 42
Appendix 44
Schematics 44

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Connections

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Power
The synthesiser is powered by a regulated 9V DC power supply, connected
by a 2.1mm DC plug tip positive polarity. The power supply needs to be tightly
regulated and should not exceed 10V at any time. Earthing is not
recommended.
Display
An SXGA video output is available on a standard HD-15 connector. The
1024x1280 pixel image is oriented 90 degrees counter-clockwise from the
typical format, and is often described as the portrait orientation (as from the
typical landscape orientation). Connections to this socket should only be
made when the power is switched off at the wall for both State Zero and the
monitor.
Audio
The stereo inputs and outputs are via balanced !” TRS plugs. Both inputs
and outputs are DC coupled to allow interfacing with CV signals to/from
modular synthesisers.
Midi
Midi input and output is on standard 5 pin 180 degree DIN connectors. The
synthesiser only responds to messages on channel 1.
Patchfield
The patch points of the synthesiser are connected with 3.5mm TS plugs. They
do not provide or accept analog signals and should not be patched to or from
any other piece of equipment. Within their field, connecting outputs together
will cause no damage but may patch to unpredictable locations. Also each
output has infinite fanout and can be connected to as many inputs as needed
without buffering.

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Module Reference

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Introduction
State Zero represents a new class of synthesiser, bringing together the
complete flexibility in the signal path of patchable systems with modern
polyphony and memory capabilities.
Signal flow is handled in the traditional method using physical patch cables to
connect modules together. The entire system follows the convention of signal
flow being from left to right, with inputs on the left of modules and their output
being on the right.
Patching is simplified by the absence of “multiples”, rather every input and
output is a pair of connected jacks allowing a signal to be endlessly chained
between inputs.
Most modules have several parameters that are continuously variable, each of
these are available as a pair of knobs and a signal input. Called “control
voltages” in conventional synthesisers there are no restrictions to signal
routing and these will be referred to as modulation inputs. The pair of knobs
set the base level of the parameter (right) and the amount by which the
modulation input signal will vary the parameter (left).

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Oscilloscope
The most prominent function of the video output is a dual timebase, 3 channel
oscilloscope.
The primary channel (green trace) follows whatever patch connection was last
made, allowing visualisation of any signal within the system. Triggering is
fixed and occurs on positive going zero crossings, while the timebase is
automatically adjusted to maintain several cycles on the screen at any time. If
the signal is too slow to effectively display as a periodic waveform, the
oscilloscope will ignore triggering and operate in roll mode.
A period counter is integrated with the primary channel to allow frequency
measurement or tuning, and operates from the same positive going zero
crossing trigger. The output is always displayed in microseconds, and is
disabled while the oscilloscope is in roll mode.
Further, a simple spectrum analyser (red trace) is available on the primary
channel. Operating from the waveform captured on screen it is scaled in
decibels vertically and octaves horizontally. Again it is disabled while the
oscilloscope is in roll mode.
The second timebase of the oscilloscope displays the left audio output (blue
trace) right audio output (yellow trace). Triggering is again fixed and occurs on
positive going zero crossings of the left audio output. An automatic timebase
the same as the primary channel is used, but operating independently.
These two channels are also applied to an X-Y trace (red) in the upper left of
the display, where the X and Y directions are driven by the left and right
channels respectively. This can be used for tuning oscillators by Lissajous
curves, or plotting transfer functions by viewing the relationship of the input
and output of a module.

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Master
Zoom
Displays the zoom level of the last knob adjusted.
Increment/Decrement
Zoom
Increases/decreases the zoom level of the last knob adjusted. Pressing both
together zeros the value.
Number
Increases/decreases the value of the last knob adjusted by a single step,
regardless of zoom control. Pressing both together zeros the value.
Program
Selects program number.
Mode
Selection of zoom, number, and program modes.

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Oscillator
Frequency
Exponential response, modulation of 50% from the master pitch source
achieves natural scaling and A440 tuning. Offset is displayed in
Octave/Semitone/Cent quantities.
Phase
Advances or retards phase of the oscillator up to 1 period. Offset is displayed
as a percentage.
Symmetry
Square:
Pulse width from 0 to 1, expressed as a percentage of full range from 0.5.
Sawtooth:
Ramp shape from negative going sawtooth to positive going sawtooth,
expressed as a percentage of full range from symmetric triangle.
Sinusoid:
No effect.
Waveform
Output selection of sinusoid, ramp, or square waveform.
Synchronization
Resets the phase of the oscillator to zero plus/minus phase offset. Triggered
by a positive going edge through zero.

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Low Frequency Oscillator
Frequency
Exponential response, modulation of 50% from the master pitch source
achieves natural scaling and A440 tuning down 6 octaves. Modulation of 50%
from the tempo rate source achieves an eighth note period. Offset is displayed
in Octave/Semitone/Cent quantities.
Phase
Advances or retards phase of the oscillator up to 1 period. Offset is displayed
as a percentage.
Waveform
Output selection of sinusoid, triangle, or positive going sawtooth waveform.
Synchronization
Resets the phase of the oscillator to zero plus/minus phase offset. Triggered
by a positive going edge through zero.

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Envelope
Rate
Exponential response, expressed in nominal units from 0 (infinite hold) to full
scale per sample.
Level
Final level of envelope stage expressed as a percentage of full scale from
zero.
Synchronization
The first stage of the envelope is triggered on a positive going edge through
zero and two stages follow it. The final stage is triggered on a negative going
edge through zero.

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