keelan
/
rttyjs
Seguir 1
Destacar 0
Cuchillo 0
Código Incidencias 0 Peticiones pull 0 Lanzamientos 0 Wiki Activity
Explorar el Código

first commit

Keelan Lightfoot hace 8 años
commit
a9892cd531
Se han modificado 3 ficheros con 448 adiciones y 0 borrados
Dividir vista Mostrar estadísticas de diff
  1. 3
    0
      README.md
  2. 110
    0
      rtty.html
  3. 335
    0
      rtty.js

+ 3
- 0
README.md Ver fichero 

@@ -0,0 +1,3 @@
1 
+# rtty.js
2 
+
3 
+A FSK modulator implemented purely in Javascript. Requires a browser with reasonbly good support for Web Audio (Chrome, Safari).

+ 110
- 0
rtty.html Ver fichero 

@@ -0,0 +1,110 @@
1 
+<html>
2 
+<head>
3 
+<meta charset="utf-8">
4 
+<meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=yes">
5 
+<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
6 
+<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
7 
+<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
8 
+<script src="rtty.js"></script>
9 
+<style>
10 
+button, input, textarea {
11 
+	margin-bottom: 10px;
12 
+}
13 
+
14 
+</style>
15 
+</head>
16 
+<body>
17 
+	<div class="container">
18 
+		<div class="row">
19 
+			<div class="col-md-12">
20 
+				<h1>rtty.js</h1>
21 
+			</div>
22 
+		</div>
23 
+
24 
+		<div class="row">
25 
+			<div class="col-md-4">
26 
+				<div class="panel panel-default">
27 
+					<div class="panel-heading"><h3 class="panel-title">Output Control</h3></div>
28 
+					<div class="panel-body">
29 
+						<b>Baud Rate:</b> <input class="form-control" id="baudrate" type="number" value="45.45">
30 
+						<b>Mark Frequency:</b> <input class="form-control" id="markfrequency" type="number" value="2125">
31 
+						<b>Space Frequency:</b> <input class="form-control" id="spacefrequency" type="number" value="2295">
32 
+						<button class="btn btn-default" id="start">Start Audio</button>
33 
+						<button class="btn btn-default" id="stop">Stop Audio</button>
34 
+						<button class="btn btn-default" id="invert">Invert</button>
35 
+					</div>
36 
+				</div>
37 
+				<div class="panel panel-default">
38 
+					<div class="panel-heading"><h3 class="panel-title">Modulator Control</h3></div>
39 
+					<div class="panel-body">
40 
+						<button class="btn btn-default" id="pause">Pause</button>
41 
+						<button class="btn btn-default" id="resume">Resume</button>
42 
+						<button class="btn btn-default" id="flush">Flush Buffer</button>
43 
+					</div>
44 
+				</div>
45 
+			</div>
46 
+			<div class="col-md-8">
47 
+				<div class="panel panel-default">
48 
+					<div class="panel-heading"><h3 class="panel-title">Input</h3></div>
49 
+					<div class="panel-body">
50 
+<textarea class="form-control" id="data" rows="14">
51 
+Is it a fact—or have I dreamt it—that, by means of electricity, the world of matter has become a great nerve, vibrating thousands of miles in a breathless point of time?
52 
+</textarea>
53 
+						<button class="btn btn-default" id="encode">Encode</button>
54 
+					</div>
55 
+				</div>
56 
+			</div>
57 
+		</div>
58 
+	</div>
59 
+</body>
60 
+<script>
61 
+
62 
+	var modulator = new RTTY({
63 
+		baudrate: parseFloat(document.querySelector('#baudrate').value),
64 
+		mark: parseFloat(document.querySelector('#markfrequency').value),
65 
+		space: parseFloat(document.querySelector('#spacefrequency').value)
66 
+	});
67 
+
68 
+	modulator.bufferEmptyCallback = function() {
69 
+	};
70 
+
71 
+	document.querySelector('#start').onclick = function() {
72 
+		document.querySelector('#baudrate').disabled=true;
73 
+		document.querySelector('#markfrequency').disabled=true;
74 
+		document.querySelector('#spacefrequency').disabled=true;
75 
+		modulator.baudrate = parseFloat(document.querySelector('#baudrate').value);
76 
+		modulator.mark = parseFloat(document.querySelector('#markfrequency').value);
77 
+		modulator.space = parseFloat(document.querySelector('#spacefrequency').value);
78 
+		modulator.startSound();
79 
+	};
80 
+
81 
+	document.querySelector('#stop').onclick = function() {
82 
+		modulator.stopSound();
83 
+		document.querySelector('#baudrate').disabled=false;
84 
+		document.querySelector('#markfrequency').disabled=false;
85 
+		document.querySelector('#spacefrequency').disabled=false;
86 
+	};
87 
+
88 
+	document.querySelector('#invert').onclick = function() {
89 
+		modulator.invert();
90 
+	};
91 
+
92 
+	document.querySelector('#pause').onclick = function() {
93 
+		modulator.pauseModulation();
94 
+	};
95 
+
96 
+	document.querySelector('#resume').onclick = function() {
97 
+		modulator.resumeModulation();
98 
+	};
99 
+
100 
+	document.querySelector('#encode').onclick = function() {
101 
+		modulator.modulate(document.querySelector('#data').value);
102 
+
103 
+	};
104 
+
105 
+	document.querySelector('#flush').onclick = function() {
106 
+		modulator.flushBuffer();
107 
+	};
108 
+
109 
+</script>
110 
+</html>

+ 335
- 0
rtty.js Ver fichero 

@@ -0,0 +1,335 @@
1 
+var RTTY = RTTY || {};
2 
+
3 
+var RTTY = function(props) {
4 
+
5 
+    this.mark = props.mark;
6 
+	this.space = props.space;
7 
+	this.baudrate = props.baudrate;
8 
+
9 
+	this.bufferEmptyCallback = null;
10 
+	this.characterDoneCallback = null;
11 
+
12 
+	this.fadeDoneCallback = null;
13 
+
14 
+    this.audioCtx = new (window.AudioContext || window.webkitAudioContext)();
15 
+
16 
+	this.osc = 0;
17 
+	this.freq = this.mark;
18 
+
19 
+	this.buffer = [];
20 
+	this.bufferOffset = 0;
21 
+
22 
+	this.idleBits = 0;
23 
+
24 
+	this.bit = 8;
25 
+	this.ct = {};
26 
+	this.figsmask = 1<<5;
27 
+	this.currentchar = 0x00;
28 
+	this.pause = false;
29 
+	this.suspend = false;
30 
+	this.source = null;
31 
+	this.figures = true;
32 
+	this.unshift = false;
33 
+	this.idle = true;
34 
+	this.bufferEmptyCalled = false;
35 
+	this.flush = null;
36 
+	this.amplitude = 1;
37 
+	this.fade = 0;
38 
+
39 
+	this.initTables();
40 
+
41 
+	this.scriptNode = this.audioCtx.createScriptProcessor(4096, 1, 1);
42 
+
43 
+	this.scriptNode.onaudioprocess = (function(audioProcessingEvent) {
44 
+		var inputBuffer = audioProcessingEvent.inputBuffer;
45 
+		var outputBuffer = audioProcessingEvent.outputBuffer;
46 
+		var inputData = inputBuffer.getChannelData(0);
47 
+		var outputData = outputBuffer.getChannelData(0);
48 
+		for (var sample = 0; sample < inputBuffer.length; sample++) {
49 
+			if (!this.suspend && inputData[sample]==1) { // bit marker
50 
+				if (this.idleBits > 0) {
51 
+					this.idleBits--;
52 
+					if (this.idleBits==0) {
53 
+						if (this.characterDoneCallback != null && typeof this.characterDoneCallback == "function") {
54 
+							this.characterDoneCallback(bufferLen);
55 
+						}
56 
+						this.idle = true;
57 
+					}
58 
+				} else if (this.pause && this.idle) {
59 
+					this.suspend = true;
60 
+					this.pause = false;
61 
+				} else if (this.idle) {
62 
+					if (this.flush != null) {
63 
+						this.buffer = [];
64 
+						this.bufferOffset = 0;
65 
+						if (typeof this.flush == "function") {
66 
+							this.flush();
67 
+						}
68 
+						this.flush = null;
69 
+					}
70 
+					var bufferLen = this.buffer.length - this.bufferOffset;
71 
+					if (bufferLen > 0)  {
72 
+						this.idle = false;
73 
+						if (this.bufferEmptyCalled) {
74 
+							this.bufferEmptyCalled = false;
75 
+						}
76 
+						var next = this.buffer[this.bufferOffset];
77 
+						if (++this.bufferOffset * 2 >= this.buffer.length){
78 
+							this.buffer  = this.buffer.slice(this.bufferOffset);
79 
+							this.bufferOffset = 0;
80 
+						}
81 
+						switch (next.type) {
82 
+						case "char":
83 
+							this.currentchar = next.val;
84 
+							break;
85 
+						case "pause":
86 
+							this.idleBits = next.val;
87 
+							break;
88 
+						case "callback":
89 
+							next.val();
90 
+							this.idle = true;
91 
+							break;
92 
+						}
93 
+					} else if (!this.bufferEmptyCalled) {
94 
+						if (this.bufferEmptyCallback != null && typeof this.bufferEmptyCallback == "function") {
95 
+							this.bufferEmptyCallback();
96 
+							this.bufferEmptyCalled = true;
97 
+						}
98 
+					}
99 
+				} else {
100 
+					if (this.bit==0) { // start
101 
+						this.freq = this.space;
102 
+					}
103 
+					if (this.bit >= 1 && this.bit <= 5) { // data bits
104 
+						this.freq = (this.currentchar&1)?this.mark:this.space;
105 
+						this.currentchar=this.currentchar>>1;
106 
+					}
107 
+					if (this.bit==6||this.bit==7) { // stop bits
108 
+						this.freq = this.mark;
109 
+					}
110 
+					if (this.bit==8) {
111 
+						this.bit=0;
112 
+						this.idle=true;
113 
+						if (this.characterDoneCallback != null && typeof this.characterDoneCallback == "function") {
114 
+							this.characterDoneCallback(bufferLen);
115 
+						}
116 
+					} else {
117 
+						this.bit++;
118 
+					}
119 
+				}
120 
+			}
121 
+
122 
+			outputData[sample] =  this.waveTable[this.osc]*this.amplitude;
123 
+			this.osc = (this.osc+this.freq)%this.audioCtx.sampleRate;
124 
+
125 
+			if (this.fade > 0 && (this.amplitude + this.fade) > 1) {
126 
+				this.fade = 0;
127 
+				this.amplitude = 1;
128 
+				if (this.fadeDoneCallback != null && typeof this.fadeDoneCallback == "function") {
129 
+					this.fadeDoneCallback();
130 
+					this.fadeDoneCallback = null;
131 
+				}
132 
+			} else if (this.fade < 0 && (this.amplitude + this.fade) < 0) {
133 
+				this.fade = 0;
134 
+				this.amplitude = 0;
135 
+				if (this.fadeDoneCallback != null && typeof this.fadeDoneCallback == "function") {
136 
+					this.fadeDoneCallback();
137 
+					this.fadeDoneCallback = null;
138 
+				}
139 
+			}
140 
+			this.amplitude += this.fade;
141 
+		}
142 
+	}).bind(this);
143 
+
144 
+}
145 
+
146 
+RTTY.prototype.initTables = function() {
147 
+	this.waveTable = new Float32Array(this.audioCtx.sampleRate);
148 
+	for (var i=0;i<this.audioCtx.sampleRate;i++) {
149 
+		this.waveTable[i] = Math.sin((i/this.audioCtx.sampleRate)*2*Math.PI);
150 
+	}
151 
+	this.ct = {
152 
+		"0": 0x36, "1": 0x37, "2": 0x33, "3": 0x21, "4": 0x2a, "5": 0x30, "6": 0x35,
153 
+		"7": 0x25, "8": 0x26, "9": 0x38, "A": 0x03, "B": 0x19, "C": 0x0e, "D": 0x09,
154 
+		"E": 0x01, "F": 0x0d, "G": 0x1a, "H": 0x14, "I": 0x06, "J": 0x0b, "K": 0x0f,
155 
+		"L": 0x12, "M": 0x1c, "N": 0x0c, "O": 0x18, "P": 0x16, "Q": 0x17, "R": 0x0a,
156 
+		"S": 0x05, "T": 0x10, "U": 0x07, "V": 0x1e, "W": 0x13, "X": 0x1d, "Y": 0x15,
157 
+		"Z": 0x11, "\r": 0x02, "\n": 0x08, "'": 0x2b, "-": 0x23, "_": 0x23, ",": 0x2c,
158 
+		"!": 0x2d, ":": 0x2e, "(": 0x2f, "+": 0x31, ")": 0x32, "#": 0x34, "?": 0x39,
159 
+		"&": 0x3a, ".": 0x3c, "/": 0x3d, ";": 0x3e, "$": 0x29
160 
+	}
161 
+};
162 
+
163 
+
164 
+RTTY.prototype.setFade = function(fade, callback) {
165 
+	this.fade = fade;
166 
+	this.fadeDoneCallback = callback;
167 
+}
168 
+
169 
+RTTY.prototype.pauseModulation = function() {
170 
+	this.pause = true;
171 
+}
172 
+
173 
+RTTY.prototype.resumeModulation = function() {
174 
+	this.suspend = false;
175 
+}
176 
+
177 
+
178 
+
179 
+RTTY.prototype.startSound = function() {
180 
+	if (this.source == null) {
181 
+		this.idle = true;
182 
+		this.amplitude = 0;
183 
+		var samplesPerSymbol = Math.floor(this.audioCtx.sampleRate/this.baudrate);
184 
+		var myArrayBuffer = this.audioCtx.createBuffer(1, samplesPerSymbol, this.audioCtx.sampleRate);
185 
+		this.source = this.audioCtx.createBufferSource();
186 
+		this.source.buffer = myArrayBuffer;
187 
+		this.source.loop = true;
188 
+
189 
+		var tickTrack = myArrayBuffer.getChannelData(0);
190 
+		tickTrack[0] = 1;
191 
+
192 
+		this.freq = this.mark;
193 
+
194 
+		this.source.connect(this.scriptNode);
195 
+		this.scriptNode.connect(this.audioCtx.destination);
196 
+		this.source.start();
197 
+
198 
+		this.setFade(.01, null);
199 
+	}
200 
+}
201 
+
202 
+RTTY.prototype.stopSound = function() {
203 
+	if (this.source != null) {
204 
+		var me = this
205 
+		this.flushBuffer(function(){
206 
+			me.setFade(-.01, function(){
207 
+				setTimeout(function(){
208 
+					me.source.stop();
209 
+	 				me.scriptNode.disconnect();
210 
+	 				me.source = null;
211 
+				}, 500);
212 
+			});
213 
+		});
214 
+	}
215 
+}
216 
+
217 
+RTTY.prototype.flushBuffer = function(callback) {
218 
+	if (callback == null) {
219 
+		callback=function(){};
220 
+	}
221 
+	this.flush = callback;
222 
+}
223 
+
224 
+RTTY.prototype.invert = function() {
225 
+	var x = this.mark;
226 
+	if (this.freq==this.mark) {
227 
+		this.freq=this.space;
228 
+	} else {
229 
+		this.freq=this.mark;
230 
+	}
231 
+	this.mark = this.space;
232 
+	this.space = x;
233 
+}
234 
+
235 
+
236 
+RTTY.prototype.modulate = function(str) {
237 
+	for (var i = 0, len = str.length; i < len; i++) {
238 
+		this.modulateChar(str[i]);
239 
+	}
240 
+}
241 
+
242 
+RTTY.prototype.modulateChar = function(c) {
243 
+	var baudot
244 
+
245 
+	var c = c.toUpperCase();
246 
+
247 
+	switch (c) {
248 
+		case 0x00: // null
249 
+			this.pushChar(0x00); // null
250 
+			break;
251 
+		case 0x0a: // lf
252 
+			this.pushChar(0x02); // cr
253 
+			this.pushChar(0x08); // lf
254 
+			break;
255 
+		case ' ': // space
256 
+			// if we print a space in figures mode, terminals set to
257 
+			// unshift on space will unshift. Remember that, so that if a
258 
+			// figures character needs to be printed, we can turn figures
259 
+			// mode back on before printing it.
260 
+			if (this.figures) {
261 
+				this.unshift = true;
262 
+			}
263 
+			this.pushChar(0x04);
264 
+			break;
265 
+		case '@': // Change @ to (at)
266 
+			this.figs();
267 
+			this.pushChar(this.ct['(']);
268 
+			this.ltrs();
269 
+			this.pushChar(this.ct['A']);
270 
+			this.pushChar(this.ct['T']);
271 
+			this.figs();
272 
+			this.pushChar(this.ct[')']);
273 
+			break;
274 
+		case '"': // use two single quotes as a double quote
275 
+			this.figs();
276 
+			this.pushChar(this.ct["'"]);
277 
+			this.pushChar(this.ct["'"]);
278 
+			break;
279 
+		default:
280 
+			baudot=this.ct[c];
281 
+			if (baudot!=undefined) {
282 
+				// correction for unshift on space
283 
+				if ((baudot&this.figsmask)&&this.figures&&this.unshift) {
284 
+					this.figs();
285 
+				}
286 
+				if ((baudot&this.figsmask)&&!this.figures) {
287 
+					this.figs();
288 
+				}
289 
+				if (!(baudot&this.figsmask)&&this.figures) {
290 
+					this.ltrs();
291 
+				}
292 
+				this.pushChar(baudot);
293 
+			}
294 
+			break;
295 
+	}
296 
+
297 
+}
298 
+
299 
+RTTY.prototype.pushChar = function(c) {
300 
+	this.buffer.push({
301 
+		type: "char",
302 
+		val: c
303 
+	});
304 
+
305 
+}
306 
+
307 
+RTTY.prototype.pushPause = function(p) {
308 
+	this.buffer.push({
309 
+		type: "pause",
310 
+		val: p
311 
+	});
312 
+}
313 
+
314 
+RTTY.prototype.pushCallback = function(callback) {
315 
+	this.buffer.push({
316 
+		type: "callback",
317 
+		val: callback
318 
+	});
319 
+}
320 
+
321 
+
322 
+RTTY.prototype.figs = function() {
323 
+	this.pushChar(0x1b); // figs
324 
+	this.figures=true;
325 
+	this.unshift=false;
326 
+}
327 
+
328 
+RTTY.prototype.ltrs = function() {
329 
+	this.pushChar(0x1f); // ltrs
330 
+	this.figures=false;
331 
+	this.unshift=false;
332 
+}
333 
+
334 
+
335 
+