Casio Phase Distortion (PD) Synthesis
Casio's patented digital synthesis architecture that alters the reading speed of a lookup sine wave to generate resonant and sawtooth waveforms without analog filters.
# Mathematical Formula & Architecture
Logic SpecificationPhi_out = piecewise_linear_distortion(Phi_in). Non-linear phase angle acceleration simulates VCF cutoff sweeps.
# Phase Distortion concept:
def distort_phase(linear_phase: float, cutoff_factor: float) -> float:
"""Accelerates early phase read to emulate resonant lowpass filter without filter ICs."""
if linear_phase < 0.5:
return linear_phase * (2.0 ** cutoff_factor)
return linear_phase# Deep Technical Analysis & Historical Context
To circumvent Yamaha's patents on FM synthesis and Roland's patents on subtractive filters, Casio engineer Masanori Sakashita developed Phase Distortion (PD) synthesis in 1984 for the CZ-101 and CZ-1000. Instead of multiplying sine waves together (like Yamaha FM) or subtracting harmonics with an analog filter (like Roland), Casio stores a pristine sine wave in ROM. By varying the velocity at which the phase angle counter traverses the sine wave during each cycle, the wave is deformed into sawtooth, pulse, double-sine, or resonant waveform shapes in real time.
Common Studio Pitfall & Hardware Hazard
Casio CZ patch SysEx format uses completely distinct non-linear 8-stage envelope rate/level parameters that cannot be translated directly to standard ADSR synth patches.
# Hardware Synthesizers Using This Technology
Click any synthesizer below to explore its specific memory protect routine, factory soundbanks, and Web MIDI SysEx cloud backup engine:
# Frequently Asked Engineering Questions
Why was the CZ-101 so popular in Detroit Techno?
Its unique resonance waveforms produced razor-sharp, bass-heavy plucks and organs without analog filter bleed, creating early techno and house signature timbres.
Related Engineering Concepts
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