db — Convert numeric values to decibels using MATLAB-compatible voltage, power, or resistance forms.

Y = db(X) converts magnitudes to decibels with 20*log10(abs(X)). db(X, 'power') uses 10*log10(abs(X)), and db(X, R) treats X as voltage across resistance R and returns 10*log10(abs(X).^2 ./ R).

Syntax

Y = db(X)
Y = db(X, 'voltage')
Y = db(X, 'power')
Y = db(X, R)

• X may be real or complex numeric data.
• R is a finite positive real numeric scalar or array.
• The output shape follows X for mode arguments and the broadcasted shape of X and R for the resistance form.

How db works

• db(X) and db(X, 'voltage') compute voltage-style decibels with 20*log10(abs(X)).
• db(X, 'power') computes power-style decibels with 10*log10(abs(X)).
• db(X, R) computes power through a finite positive resistance with 10*log10(abs(X).^2 ./ R).
• Complex inputs are converted through their magnitude before applying the decibel formula.
• The resistance form supports MATLAB implicit expansion between X and R.
• Zero input returns -Inf, matching the logarithm singularity at zero.
• Integer and logical inputs are promoted to double precision.

Examples

Voltage-style decibel conversion

y = db(10)

Expected output:

y = 20

Power-style decibel conversion

p = db(100, 'power')

Expected output:

p = 20

Voltage across a reference resistance

p = db(10, 50)

Expected output:

p = 3.0103

Complex magnitude conversion

z = db(3 + 4i)

Expected output:

z = 13.9794

FAQ

Related Control functions

Open-source implementation

Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how db works, line by line, in Rust.

• View db.rs on GitHub
• Learn how the runtime works
• Found a bug? Open an issue with a minimal reproduction.

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