# ER-301/Aliasing Triangle

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## Applications

• Thru-zero FM synthesis
• LFO with sync capabilities

## Description

This unit is a simple triangle oscillator with inputs for both exponential and linear FM, and an internal VCA on its output. The linear FM supports thru-zero operation.

## Parameters

### V/oct

 Control Type Has Sub-chain? Sub-chain Parameters Fader Scale Pitch yes transpose (-3600¢ to 3600¢) logarithmic ratio

This parameter is used to transpose the base frequency up or down according to an incoming modulation value that is V/oct calibrated (typically one of the inputs from the ABCD matrix). In other words,

$\displaystyle \text{f} = \text{f0} * 2 ^{\frac{x}{1200}}$

where $\displaystyle x$ is the value of this parameter (which is in cents). For example, if the base frequency (f0) is equal to 55Hz and this V/oct parameter is set to 2400¢, then the resulting frequency will be 220Hz (i.e. 2400¢ = 2 octaves which is 4x).

### f0

 Control Type Has Sub-chain? Sub-chain Parameters Fader Scale Gain/Bias yes gain (-10,000 to 10,000) bias (10 octaves above and below 27.5Hz) frequency in Hertz

This parameter sets the fundamental frequency that is subsequently transposed by the V/oct parameter. Modulating this parameter corresponds to (thru-zero) linear FM.

### sync

 Control Type Has Sub-chain? Sub-chain Parameters Behavior Threshold yes threshold (-1 to 1) trigger

A trigger into this parameter will cause the oscillator to reset its phase accumulator to zero. This is equivalent to the hard-sync on many oscillators.

 This sync operation is not anti-aliased. So audio-rate triggering of this parameter will exhibit strong anti-aliasing artifacts which depending on the desired result could be a good thing or a bad thing.

### level

 Control Type Has Sub-chain? Sub-chain Parameters Fader Scale Gain/Bias yes gain (-10 to 10) bias (-1 to 1) linear gain

This parameter controls an internal bipolar linear VCA on the output of the unit. It behaves exactly the same as the level parameter of a Linear Bipolar VCA unit.