Block type: signalGenerator
| Parameter | Description |
|---|---|
| input ports | No input ports (this block has none). |
| Parameter | Description |
|---|---|
| output ports | 1 output port(s) declared. |
Configurable periodic source: sine, square or sawtooth (Amplitude, Frequency).
| Module | nflow_blocks |
| Library | Source |
| Type | signalGenerator |
| Label | Signal Generator |
Description
A configurable periodic source with no input. Waveform is "sine", "square" or "sawtooth", scaled by Amplitude, with Frequency in Hz. sine = A*sin(2*pi*f*t); square = A*sign(sin(2*pi*f*t)); sawtooth ramps linearly from -A to +A over each period. Stateless (a pure function of time).
Ports
This block has no input ports.
Output(s)
| Port | Role | Side | Position |
|---|---|---|---|
| Port_1 | Numeric signal produced by the block. | right | x=80, y=40 |
Parameters
| Parameter | Default value |
|---|---|
Waveform |
sine |
Amplitude |
1 |
Frequency |
1 |
Block Characteristics
| Block type | signalGenerator |
| Family | Source |
| Rendered size | 80 x 80 |
| Phases | OUTPUT |
| Internal state or history | no |
| Signal data type | double numeric values |
Algorithms
Equation or Rule
$$y(t) = A\,\sin(2\pi f t) \quad(\text{sine})$$Extended Capabilities
Code generation: supported for C and Rust.
Implementation Sources
modules/nflow_blocks/libraries/source/library.json{
"id": "builtin.source",
"title": "Source",
"version": "1.0.0",
"format": "nflow-2",
"metadata": {
"author": "Allan CORNET",
"created": "2026-03-21",
"tool": "Nelson nflow"
},
"comment": "Basic source blocks",
"license": "LGPL-3.0",
"builtin": true,
"blocks": [
{
"type": "constant",
"label": "Constant",
"icon": "constant.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"Value": 1,
"OutDataType": "double"
},
"render": {
"type": "math",
"bodyClass": "block-body",
"mathGroupClass": "constant-math",
"formula": "{params.Value}"
}
},
{
"type": "step",
"label": "Step",
"icon": "step.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"Time": 0
},
"render": {
"type": "image",
"src": "step.svg"
}
},
{
"type": "ramp",
"label": "Ramp",
"icon": "ramp.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"slope": 1,
"start": 0
},
"render": {
"type": "image",
"src": "ramp.svg"
}
},
{
"type": "counterFreeRunning",
"label": "Counter Free-Running",
"icon": "counterFreeRunning.svg",
"phases": [
"INIT",
"OUTPUT",
"UPDATE"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"NumBits": 16
},
"render": {
"type": "image",
"src": "counterFreeRunning.svg"
}
},
{
"type": "counterLimited",
"label": "Counter Limited",
"icon": "counterLimited.svg",
"phases": [
"INIT",
"OUTPUT",
"UPDATE"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"UpperLimit": 7
},
"render": {
"type": "image",
"src": "counterLimited.svg"
}
},
{
"type": "repeatingSequenceStair",
"label": "Repeating Sequence Stair",
"icon": "repeatingSequenceStair.svg",
"phases": [
"INIT",
"OUTPUT",
"UPDATE"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"OutValues": [
0,
1,
2,
3,
2,
1
]
},
"render": {
"type": "image",
"src": "repeatingSequenceStair.svg"
}
},
{
"type": "repeatingSequenceInterpolated",
"label": "Repeating Sequence Interpolated",
"icon": "repeatingSequenceInterpolated.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"TimeValues": [
0,
1,
2
],
"OutValues": [
0,
2,
0
]
},
"render": {
"type": "image",
"src": "repeatingSequenceInterpolated.svg"
}
},
{
"type": "signalGenerator",
"label": "Signal Generator",
"icon": "signalGenerator.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"Waveform": "sine",
"Amplitude": 1,
"Frequency": 1
},
"render": {
"type": "image",
"src": "signalGenerator.svg"
}
},
{
"type": "pulse",
"label": "Pulse Generator",
"icon": "pulse.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"Amplitude": 1,
"Period": 1,
"Width": 50,
"StartTime": 0,
"Offset": 0
},
"render": {
"type": "image",
"src": "pulse.svg"
}
},
{
"type": "impulse",
"label": "Impulse",
"icon": "impulse.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"Time": 0,
"Amplitude": 1
},
"render": {
"type": "image",
"src": "impulse.svg"
}
},
{
"type": "sine",
"label": "Sine",
"icon": "sine.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"Amplitude": 1,
"Frequency": 1,
"Phase": 0
},
"render": {
"type": "image",
"src": "sine.svg"
}
},
{
"type": "chirp",
"label": "Chirp",
"icon": "chirp.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"Amplitude": 1,
"f1": 1,
"f2": 10,
"T": 10
},
"render": {
"type": "image",
"src": "chirp.svg"
}
},
{
"type": "fileSource",
"label": "File",
"icon": "fileSource.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"FileName": ""
},
"render": {
"type": "image",
"src": "fileSource.svg"
}
},
{
"type": "fromWorkspace",
"label": "From Workspace",
"icon": "fromWorkspace.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 48,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 24,
"side": "right"
}
],
"defaultParams": {
"VariableName": "simin",
"SampleTime": "0",
"Interpolate": "on",
"OutputAfterFinalValue": "Extrapolation"
},
"render": {
"type": "math",
"formula": "\\mathtt{{params.VariableName}}",
"textSize": 14
}
},
{
"type": "labelSource",
"label": "Label",
"icon": "labelSource.svg",
"phases": [
"OUTPUT"
],
"width": 40,
"height": 40,
"inputs": [],
"outputs": [
{
"x": 40,
"y": 20,
"side": "right"
}
],
"defaultParams": {
"GotoTag": "x"
},
"render": {
"type": "image",
"src": "labelSource.svg"
}
},
{
"type": "noise",
"label": "Noise",
"icon": "noise.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"Amplitude": 1
},
"render": {
"type": "image",
"src": "noise.svg"
}
},
{
"type": "clock",
"label": "Clock",
"icon": "clock.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 80,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"DisplayTime": false,
"Decimation": 10
},
"render": {
"type": "image",
"src": "clock.svg",
"svgMode": "element",
"preserveAspectRatio": "none",
"x": 0,
"y": 0,
"width": 80,
"height": 80
}
},
{
"type": "enumeratedConstant",
"label": "Enumerated Constant",
"icon": "enumeratedConstant.svg",
"phases": [
"OUTPUT"
],
"width": 90,
"height": 50,
"inputs": [],
"outputs": [
{
"x": 90,
"y": 25,
"side": "right"
}
],
"defaultParams": {
"EnumClass": "",
"Value": 0
}
}
]
}
modules/nflow_blocks/src/cpp/source/signalGenerator.cpp//=============================================================================
// Copyright (c) 2016-present Allan CORNET (Nelson)
//=============================================================================
// This file is part of Nelson.
//=============================================================================
// LICENCE_BLOCK_BEGIN
// SPDX-License-Identifier: LGPL-3.0-or-later
// LICENCE_BLOCK_END
//=============================================================================
// signalGenerator: a configurable periodic source (Signal Generator). Waveform
// is "sine", "square" or "sawtooth"; Amplitude scales it and Frequency is in Hz.
// sine = A*sin(2*pi*f*t); square starts LOW, i.e. -A*sign(sin(2*pi*f*t));
// sawtooth ramps linearly DOWN from +A to -A over each period. No input;
// scalar output; stateless (a pure function of time). C / Rust code generation.
//=============================================================================
#include "SimEngineTypes.hpp"
#include "BlockRegistry.hpp"
#include "FieldNames.hpp"
#include "NFlowBlockDescriptor.hpp"
#include <cmath>
#include <string>
#include "source_blocks.hpp"
//=============================================================================
namespace Nelson {
namespace NFlow {
//=============================================================================
// Waveform codes: 0 sine, 1 square, 2 sawtooth.
static int
sigGenWave(const nflow::BlockDescriptor& bd)
{
const std::string w = bd.paramStr("Waveform", "sine");
if (w == "square") {
return 1;
}
if (w == "sawtooth") {
return 2;
}
return 0;
}
//=============================================================================
bool
handleSignalGenerator(SimCtx& ctx, const Block& b, Phase phase)
{
if (phase != Phase::OUTPUT) {
return false;
}
nflow::BlockDescriptor bd(b, ctx.variables);
const double amp = bd.paramDouble("Amplitude", 1.0);
const double freq = bd.paramDouble("Frequency", 1.0);
const int wave = sigGenWave(bd);
const double t = ctx.t;
double v = 0.0;
if (wave == 1) {
// A period opens on the LOW half and turns at the half-period. Read
// from the phase, not from sin(): sin(pi) is a small POSITIVE
// residue in binary, so the turn landed one sample late.
const double ph = freq * t;
v = ((ph - std::floor(ph)) < 0.5) ? -1.0 : 1.0;
} else if (wave == 2) {
// A period opens at +A and ramps down to -A.
const double ph = freq * t;
v = 1.0 - 2.0 * (ph - std::floor(ph));
} else {
v = std::sin(2.0 * M_PI * freq * t);
}
setOutput(ctx, b.nid, amp * v);
return false;
}
//=============================================================================
BlockCodegenTemplate
getCodeGenCSignalGenerator()
{
BlockCodegenTemplate t;
t.emitStep = [](const BlockCodegenArgs& a) {
nflow::BlockDescriptor bd(*a.block, *a.variables);
const double amp = bd.paramDouble("Amplitude", 1.0);
const double freq = bd.paramDouble("Frequency", 1.0);
const int wave = sigGenWave(bd);
const std::string A = nflow::formatNumber(amp);
const std::string omega = nflow::formatNumber(2.0 * M_PI * freq);
const std::string f = nflow::formatNumber(freq);
std::string expr;
if (wave == 1) {
expr = A + " * (((" + f + " * t - floor(" + f + " * t)) < 0.5) ? -1.0 : 1.0)";
} else if (wave == 2) {
expr = A + " * (1.0 - 2.0 * (" + f + " * t - floor(" + f + " * t)))";
} else {
expr = A + " * sin(" + omega + " * t)";
}
a.line("out_" + a.id + " = " + expr + ";");
};
return t;
}
//=============================================================================
BlockCodegenTemplate
getCodeGenRustSignalGenerator()
{
BlockCodegenTemplate t;
t.emitStep = [](const BlockCodegenArgs& a) {
nflow::BlockDescriptor bd(*a.block, *a.variables);
const double amp = bd.paramDouble("Amplitude", 1.0);
const double freq = bd.paramDouble("Frequency", 1.0);
const int wave = sigGenWave(bd);
const std::string A = a.fmt(amp);
const std::string omega = a.fmt(2.0 * M_PI * freq);
const std::string f = a.fmt(freq);
std::string expr;
if (wave == 1) {
expr = A + " * (if (" + f + " * t - (" + f
+ " * t).floor()) < 0.5_f64 { -1.0_f64 } else { 1.0_f64 })";
} else if (wave == 2) {
expr = A + " * (1.0_f64 - 2.0_f64 * (" + f + " * t - (" + f + " * t).floor()))";
} else {
expr = A + " * (" + omega + " * t).sin()";
}
a.line("out_" + a.id + " = " + expr + ";");
};
return t;
}
//=============================================================================
} // namespace NFlow
} // namespace Nelson
//=============================================================================
d.blocks={ struct('id','g','type','signalGenerator','inputs',0,'outputs',1,'params',struct('Waveform','sine','Amplitude',2,'Frequency',1)), struct('id','w','type','toWorkspace','inputs',1,'outputs',0,'params',struct('VariableName','y','SaveFormat','Array')) };
d.connections={ struct('from','g','to','w','fromIndex',0,'toIndex',0) };
d.sampleTime=0.1; d.duration=1.0; d.solver='discrete'; d.variables=struct();
r=jsondecode(__nflow_simulate__(jsonencode(d)));| Version | Description |
|---|---|
| 1.0.0 | initial version |