Struct SlewRateLimiter 

pub struct SlewRateLimiter { /* private fields */ }

Models op-amp slew rate limiting for physically accurate WDF processing.

Real op-amps have a finite maximum rate of output voltage change (dV/dt), measured in V/µs. When the signal demands a faster slew than the op-amp can deliver, the output “rounds off” — this is the mechanism behind the distinctive compression character of slow op-amps like the LM308 (RAT) versus fast ones like the TL072 (Klon).

The slew rate limiter operates as a per-sample voltage clamp on the derivative: |V[n] - V[n-1]| ≤ slew_rate * dt, where dt = 1/fs.

This is NOT a WDF root — it sits in the signal path between stages, modeling the op-amp’s output stage limitation. Thin wrapper over the shared [crate::stage::NonIdealFxState] dV/dt clamp.

Carries NO copy of the slew math: process delegates to NonIdealFxState::slew_step (the single source of truth) and only adds the finite guard. Only test code uses this type now — the live SPQR pipeline applies slew in-loop via NonIdealFxState directly.

Implementations

impl SlewRateLimiter

pub fn new(slew_rate_v_per_us: f64, sample_rate: f64) -> SlewRateLimiter

Create a slew rate limiter from a slew rate in V/µs and sample rate.

Slew rate values from real op-amps:

• LM308: 0.3 V/µs (the RAT’s character)
• LM741: 0.5 V/µs (vintage slow)
• JRC4558: 1.7 V/µs (Tube Screamer warmth)
• NE5532: 9.0 V/µs (studio clean)
• TL072: 13.0 V/µs (modern, transparent)
• CA3080: 50.0 V/µs (OTA, essentially transparent)

pub fn process(&mut self, input: f64) -> f64

Process one sample through the slew rate limiter.

If the requested voltage change exceeds what the op-amp can deliver in one sample period, the output is clamped to the maximum slew rate. This creates asymmetric HF compression — the exact behavior that makes the LM308 RAT sound different from a TL072 RAT.

pub fn set_sample_rate(&mut self, sample_rate: f64)

Update sample rate and recompute max_dv.

pub fn reset(&mut self)

Reset internal state.

pub fn slew_rate(&self) -> f64

Get the slew rate in V/µs.

pub fn is_limiting(&self) -> bool

Check if slew limiting is currently active (for diagnostics).

Returns the ratio of actual dV to max_dv for the last sample. Values > 1.0 mean the limiter was engaged.

Trait Implementations

impl Clone for SlewRateLimiter

fn clone(&self) -> SlewRateLimiter

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for SlewRateLimiter

impl Debug for SlewRateLimiter

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.