---
cssclasses:
  - img-grid
  - img-zoom
date created: 2025-09-27
date modified: 2025-09-27 11:23
tags:
  - OSC
backlinks:
  - "[[Drambo ♔]]"
  - "[[♯ OSC]]"
description:
  - The basic element (operator) of FM synthesis.An internal oscillator's frequency or phase is linearly modulated by FM input (autoconnected).
image: "[[FM-Op.png]]"
permalink: fm-op-module
published: true
---
# FM Operator

The basic element (operator) of FM[^1] synthesis.

An internal oscillator's frequency or phase is linearly modulated by FM input (autoconnected). 

Internal feedback changes oscillator waveshape from square wave through sine to saw. 

Frequency ratio may be set to zero. In this case the FM Operator "is stopped" and acts like a sophisticated waveshaper / through-zero oscillator.

- **FM Amount;**
	- Controls how much modulator (connected to FM input) affects FM modulation.
- **Ratio;** 
	- Base frequency ratio
- **Detune;**  
	- Base frequency detune
- **Mod;** 
	- Phase / Freq - switch between phase or linear frequency modulation
- **Feedback;** 
	- Amount of output signal that is internally fed back to FM input. Changes waveshape: square-sine-saw
- **Attack, Decay;** 
	- Set attack and decay length of internal amp envelope
- **Retrig;** 
	- Determines if oscillator should restart phase on each trigger
- **Velocity;** 
	- Amount of velocity influence on amp envelope level
- **End level;** 
	- Bottom level of amplitude envelope generator

Combine several FM Operators in series or using mixer to achieve different FM structures.

![[FM-Op.png]]


[^1]: FM | Frequency Modulation