Sources

SignalGenerator Block

Generates various types of time-varying signals (sine, cosine, square, sawtooth, triangle)

# SignalGenerator Block

Description

The SignalGenerator block is a versatile signal source that generates various types of time-varying signals for simulation and testing purposes. It can produce sinusoidal waves, cosine waves, square waves, sawtooth waves, and triangular waves. This block is essential for creating test signals, reference inputs, and periodic disturbances in control systems and signal processing applications.

The SignalGenerator operates as a time-based function generator, producing output signals based on the current simulation time and the configured parameters. It has no input ports and continuously outputs the generated signal to its single output port.

Mathematical Model

All signals share the base argument:

θ(t) = 2π × f × t + φ

where φ is the phase converted from degrees to radians.

The normalized position within the cycle is:

n = ((θ / 2π) mod 1 + 1) mod 1

Sinusoidal Signal

y(t) = A × sin(θ) + offset

Cosine Signal

y(t) = A × cos(θ) + offset

Square Wave Signal

y(t) = A      if n < dutyCycle
y(t) = -A     if n >= dutyCycle
y(t) += offset

Sawtooth Wave Signal

y(t) = A × (2n - 1) + offset

Rises linearly from -A to +A over one period.

Triangular Wave Signal

y(t) = A × (4n - 1)       if n < 0.5
y(t) = A × (3 - 4n)       if n >= 0.5
y(t) += offset

Rises from -A to +A in the first half, falls from +A to -A in the second half.

Where:

y(t) is the output signal at time t
A is the amplitude parameter
f is the frequency parameter (Hz)
φ is the phase parameter (degrees, converted to radians internally)
offset is the DC offset parameter
n is the normalized position in the cycle (0 to 1)

Parameters

signalType

The type of waveform to generate.

Type: select
Options: sine, cosine, square, sawtooth, triangle
Default: sine
Tooltip: Type of periodic signal to generate
sine: Smooth sinusoidal waveform (ideal for continuous systems)
cosine: Cosine waveform (90° phase-shifted sine)
square: Square wave with configurable duty cycle (digital signals, PWM)
sawtooth: Linear rising ramp (oscilloscope sweep, modulation)
triangle: Symmetric triangular waveform (function generation)

amplitude

The peak amplitude of the generated signal. Controls the maximum deviation from the offset value.

Type: number
Symbol: A
Range: 0.001 to 1000000
Default: 1
Tooltip: Peak amplitude of the signal

frequency

The frequency of the generated signal in Hertz (Hz).

Type: number
Symbol: f
Range: 0.001 to 100000 Hz
Default: 1
Tooltip: Signal frequency in Hertz

offset

The DC offset added to the signal. Shifts the entire signal up or down.

Type: number
Default: 0
Tooltip: DC offset added to the signal

phase

The phase offset of the signal in degrees (0-360). The phase is converted to radians internally: φ_rad = phase × π / 180. A phase of 90° on a sine wave produces a cosine wave.

Type: number
Symbol: φ
Range: 0 to 360 degrees
Default: 0
Tooltip: Initial phase offset in degrees

dutyCycle

The fraction of the period during which the square wave is at +amplitude. Only visible when signalType is "square".

Type: number
Range: 0 to 1
Default: 0.5
Tooltip: Duty cycle for square wave (0-1)
dutyCycle = 0.5: symmetric square wave (equal high/low time)
dutyCycle = 0.25: high for 25% of the period, low for 75%
dutyCycle = 0.9: high for 90% of the period (wide pulse)

Examples

1Hz Sine Wave

Generate a basic unit-amplitude sine wave:

SignalGenerator (signalType: "sine", frequency: 1) → NumericDisplay

PWM Signal

Generate a 10Hz PWM signal with 30% duty cycle:

SignalGenerator (signalType: "square", frequency: 10, dutyCycle: 0.3) → Controller

Phase-Shifted Cosine

Two equivalent ways to generate a cosine:

SignalGenerator (signalType: "cosine", frequency: 1) → Scope
SignalGenerator (signalType: "sine", frequency: 1, phase: 90) → Scope

Remarks

Phase Convention: Phase is specified in degrees (0-360) and shifts the signal forward in time. A positive phase advances the waveform.
Time-Based: Signals are calculated from the current simulation time. The block is stateless — output depends only on time and parameters.
WASM Optimized: Implemented in Rust for high-frequency signal generation without performance lag.
Negative Time Handling: The normalized position uses double-modulo ((x % 1 + 1) % 1) to handle negative argument values correctly.
Duty Cycle Clamping: The duty cycle value is clamped to [0, 1] regardless of the input value.