lotsa changes

README.md

@@ -1,5 +1,41 @@
-# Gobaudot
+# gortty
 
-Derived from the Open Baudot C library created David Rowe:
+gortty is a RTTY modulator/demodulator library for the Go language. The guts of it were derived from the openbaudot C library created David Rowe:
 
-// sourceforge link
+https://sourceforge.net/projects/openbaudot/
+
+# Architecture
+The library is based around 4 signal processing modules:
+
+## Encoder
+Converts UTF8 strings into 5 level code, supporting the following alphabets: 
+
+- TDD
+- US TTY
+- US ITA2
+- US Weather
+- US Fractions
+
+In addition to basic code translation, the coder inserts the necessary shift and unshift control codes as required. It also ensures that line length limits are respected. While all of the currently implemented alphabets are 5 unit codes, the library supports up to 8 unit codes.
+
+## Modulator
+From the coded output produced by the encoder, the modulator generates a 16 bit signed audio FSK waveform. Baud rate, fractional stop bits, marking and spacing frequencies are all configurable.
+
+## Demodulator
+Accepting a 16 bit signed audio FSK waveform as input, the demodulator generates a stream of coded characters. Supporting the same configuration flexibility as the modulator, the demodulator also supports an auto-baud mode to automatically recover the baud rate from a received samples.
+
+## Decoder
+The decoder operates in reverse of the encoder.
+
+# License
+
+This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.
+
+# Author
+
+This library was created Keelan Lightfoot. The baudot translation and DSP sections are based closely on the work of David Rowe in his openbaudot C library.
+
+# Change Log
+
+## 1.0.0
+ - Initial release

code.go

@@ -9,7 +9,7 @@
 // the Free Software Foundation; either version 2.1 of the License, or (at
 // your option) any later version.
 
-package gobaudot
+package gortty
 
 import "unicode"
 

common.go

@@ -11,7 +11,7 @@
 
 // Package gobaudot provides a set of tools to encode, modulate, demodulate and
 // baudot/TTY/RTTY data streams
-package gobaudot
+package gortty
 
 import "math"
 

decoder.go

@@ -9,7 +9,7 @@
 // the Free Software Foundation; either version 2.1 of the License, or (at
 // your option) any later version.
 
-package gobaudot
+package gortty
 
 // Decoder converts a stream of bytes representing baudot codes into a stream
 // of unicode runes.

demodulator.go

@@ -9,7 +9,7 @@
 // the Free Software Foundation; either version 2.1 of the License, or (at
 // your option) any later version.
 
-package gobaudot
+package gortty
 
 import (
 	//"fmt"

dsp.go

@@ -9,7 +9,7 @@
 // the Free Software Foundation; either version 2.1 of the License, or (at
 // your option) any later version.
 
-package gobaudot
+package gortty
 
 import "math"
 

encoder.go

@@ -9,7 +9,7 @@
 // the Free Software Foundation; either version 2.1 of the License, or (at
 // your option) any later version.
 
-package gobaudot
+package gortty
 
 
 // Encoder is fun

examples/audioin/main.go

@@ -4,12 +4,12 @@ import (
 	"fmt"
 
 	"github.com/gordonklaus/portaudio"
-	"github.com/naleek/openbaudot"
+	"github.com/naleek/gortty"
 )
 
 func main() {
 
-	s := &gobaudot.ModemSettings{
+	s := &gortty.ModemSettings{
 		Baud:       45,
 		StopBits:   2,
 		DataBits:   5,
@@ -27,7 +27,7 @@ func main() {
 		panic(err)
 	}
 	defer stream.Close()
-	charset := gobaudot.LoadCharset(&gobaudot.USTTY)
+	charset := gortty.LoadCharset(&gortty.USTTY)
 	//
 	// encoderIn := make(chan rune)
 	// modulatorIn := make(chan byte)
@@ -39,10 +39,10 @@ func main() {
 	//done := make(chan struct{})
 
 	//sig := make(chan [2]float64)
-	// encoder := gobaudot.NewEncoder(encoderIn, modulatorIn, charset)
-	// gobaudot.NewModulator(s, modulatorIn, demodulatorIn)
-	gobaudot.NewDemodulator(s, demodulatorIn, decoderIn)
-	gobaudot.NewDecoder(decoderIn, decoderOut, charset)
+	// encoder := gortty.NewEncoder(encoderIn, modulatorIn, charset)
+	// gortty.NewModulator(s, modulatorIn, demodulatorIn)
+	gortty.NewDemodulator(s, demodulatorIn, decoderIn)
+	gortty.NewDecoder(decoderIn, decoderOut, charset)
 
 	go func() {
 		for {

examples/demtest.go

@@ -5,7 +5,7 @@ import (
 	"math"
 	"math/rand"
 
-	"github.com/naleek/openbaudot"
+	"github.com/naleek/gortty"
 )
 
 // 96000 = 14
@@ -34,7 +34,7 @@ func dostuff(freq int) float64 {
 
 	done := make(chan bool)
 
-	s := &openbaudot.ModemSettings{
+	s := &gortty.ModemSettings{
 		Baud:       45,
 		StopBits:   2,
 		DataBits:   5,
@@ -102,7 +102,7 @@ func dostuff(freq int) float64 {
 		done <- true
 	}()
 
-	openbaudot.NewDumbDemodulator(s, demodulatorIn, demodulatorOut)
+	gortty.NewDumbDemodulator(s, demodulatorIn, demodulatorOut)
 	c := 0
 	running := true
 	var r float64

examples/foo/main.go

@@ -1,176 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	"github.com/gordonklaus/portaudio"
-	"github.com/naleek/openbaudot"
-)
-
-// CLoIP
-// Current Loop over IP
-// A Terrible Protocol
-// Based on TCP (because latency really doesn't matter)
-// Full duplex
-
-// client-server protocol
-// server handles pairing
-// client handles encoding/decoding
-
-/*
-
-SERVER
-
-<client connects>
-
->> greeting message
-<< IAM <client ID>
->> 200 ok
-
-<< RATE 1000
->> 200 ok
-
-<< WAIT
->> 200 ok <connection ID>
-
-
-
-<< JOIN <connection ID>
->> 200 ok
-
-
-
-
-*/
-
-type Frame struct {
-	Seq		uint32
-	Len		uint32
-	Samples []byte
-}
-
-func main() {
-
-	s := &gobaudot.ModemSettings{
-		Baud:       45,
-		StopBits:   2,
-		DataBits:   5,
-		SampleRate: 8000,
-		OneFreq:    2125,
-		ZeroFreq:   2295,
-	}
-
-	portaudio.Initialize()
-	defer portaudio.Terminate()
-
-	in := make([]int16, 64)
-	stream, err := portaudio.OpenDefaultStream(1, 0, float64(s.SampleRate), len(in), in)
-	if err != nil {
-		panic(err)
-	}
-	defer stream.Close()
-	
-	chopperIn := make(chan int16)
-	chopperOut := make(chan gobaudot.TimeSlice)
-	
-	gobaudot.NewChopper(s, chopperIn, chopperOut)
-
-
-	var buff byte
-	var bits int
-	x := 0
-	
-	sampleRate := 500
-	
-	rollover := s.SampleRate/sampleRate
-	
-	fmt.Println("Data Rate: ", sampleRate/8, "bytes per second")
-	fmt.Println(rollover)
-	
-	go func() {
-		for {
-			r := <-chopperOut
-			x++
-			
-			if r.Carrier && x%rollover==0 {
-				buff = buff << 1
-				bits++
-				if r.Marking {
-					buff = buff | 0x01
-				}
-				if bits == 8 {
-					fmt.Printf("%x",buff)
-					bits = 0
-					buff = 0
-				}
-				//fmt.Println(r.LpfVal, r.ThreshVal)
-			}
-		}
-	}()
-
-	stream.Start()
-	for {
-		stream.Read()
-		for i := range in {
-			chopperIn <- in[i]
-		}
-
-	}
-	//stream.Stop()
-
-	// go func() {
-	// 	encoder.EncodeString("hello world")
-	// 	time.Sleep(2000 * time.Millisecond)
-	// 	done <- struct{}{}
-	// }()
-
-}
-
-// // NewOBL is fun
-// func NewOBL(baud float64, callback Callback) *OBL {
-//
-// 	obl := new(OBL)
-//
-// 	obl.charset = USTTY.initialize()
-//
-// 	obl.callback = callback
-//
-// 	obl.mod.sinLutQ15 = make([]int16, 16384)
-// 	for i := 0; i < 16384; i++ {
-// 		obl.mod.sinLutQ15[i] = int16(32767 * math.Sin(2.0*math.Pi*float64(i)/float64(16384)))
-// 	}
-//
-// 	/* regular reset */
-// 	obl.autobaud.enabled = true
-// 	obl.Reset(baud)
-//
-// 	go func() {
-// 		portaudio.Initialize()
-// 		defer portaudio.Terminate()
-//
-// 		x := make(chan int16, 300)
-//
-// 		stream, _ := portaudio.OpenDefaultStream(0, 1, float64(sampleRate), 0, func(out []int16) {
-// 			for i := range out {
-// 				out[i] = <-x
-// 			}
-// 		})
-//
-// 		stream.Start()
-//
-// 		for {
-// 			s := <-obl.mod.output
-// 			//go func() {
-// 			obl.demod.input <- s
-// 			x <- s
-// 			//}()
-// 			//	binary.Write(f, binary.LittleEndian, s)
-// 		}
-// 	}()
-//
-// 	go obl.Modulate()
-// 	go obl.Demodulate()
-//
-// 	return obl
-// }

examples/main.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"time"
 
-	"github.com/naleek/openbaudot"
+	"github.com/naleek/gortty"
 )
 
 type TTYFrame struct {
@@ -15,7 +15,7 @@ type TTYFrame struct {
 
 func main() {
 
-	s := &gobaudot.ModemSettings{
+	s := &gortty.ModemSettings{
 		Baud:       45,
 		StopBits:   2,
 		DataBits:   5,
@@ -24,7 +24,7 @@ func main() {
 		ZeroFreq:   2295,
 	}
 
-	charset := gobaudot.LoadCharset(&gobaudot.USTTY)
+	charset := gortty.LoadCharset(&gortty.USTTY)
 
 	encoderIn := make(chan rune)
 	modulatorIn := make(chan byte)
@@ -34,18 +34,18 @@ func main() {
 //	decoderOut := make(chan rune)
 
 	chopperIn := make(chan int16)
-	chopperOut := make(chan gobaudot.TimeSlice)
+	chopperOut := make(chan gortty.TimeSlice)
 	
 	done := make(chan struct{})
 
 	//sig := make(chan [2]float64)
-	encoder := gobaudot.NewEncoder(encoderIn, modulatorIn, charset)
-	gobaudot.NewModulator(s, modulatorIn, chopperIn)
-//	gobaudot.NewModulator(s, modulatorIn, demodulatorIn)
-	//gobaudot.NewDemodulator(s, demodulatorIn, decoderIn)
-//	gobaudot.NewDecoder(decoderIn, decoderOut, charset)
+	encoder := gortty.NewEncoder(encoderIn, modulatorIn, charset)
+	gortty.NewModulator(s, modulatorIn, chopperIn)
+//	gortty.NewModulator(s, modulatorIn, demodulatorIn)
+	//gortty.NewDemodulator(s, demodulatorIn, decoderIn)
+//	gortty.NewDecoder(decoderIn, decoderOut, charset)
 
-	gobaudot.NewChopper(s, chopperIn, chopperOut)
+	gortty.NewChopper(s, chopperIn, chopperOut)
 
 	go func() {
 		encoder.EncodeString("hello world")

examples/rawdemod/main.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/gordonklaus/portaudio"
+	"github.com/naleek/gortty"
+)
+
+
+type Frame struct {
+	Seq		uint32
+	Len		uint32
+	Samples []byte
+}
+
+func main() {
+
+	s := &gortty.ModemSettings{
+		Baud:       45,
+		StopBits:   2,
+		DataBits:   5,
+		SampleRate: 8000,
+		OneFreq:    2125,
+		ZeroFreq:   2295,
+	}
+
+
+	portaudio.Initialize()
+	defer portaudio.Terminate()
+
+	in := make([]int16, 64)
+	
+	stream, err := portaudio.OpenDefaultStream(1, 0, float64(s.SampleRate), len(in), in)
+	if err != nil {
+		panic(err)
+	}
+	defer stream.Close()
+	
+	RawDemodulatorIn := make(chan int16)
+	RawDemodulatorOut := make(chan gortty.DCSignal)
+	
+	gortty.NewRawDemodulator(s, RawDemodulatorIn, RawDemodulatorOut)
+	
+
+	stream.Start()
+	
+	go func() {
+		for v := range RawDemodulatorOut {
+			fmt.Println(v)
+		}
+	}()
+	
+	for {
+		stream.Read()
+		for i := range in {
+			RawDemodulatorIn <- in[i]
+		}
+	}
+	
+	
+
+}

examples/rawinrawout/main.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"github.com/gordonklaus/portaudio"
+	"github.com/naleek/gortty"
+	//"fmt"
+)
+
+
+
+func main() {
+
+	s := &gortty.ModemSettings{
+		Baud:       45,
+		StopBits:   2,
+		DataBits:   5,
+		SampleRate: 8000,
+		OneFreq:    1444,
+		ZeroFreq:   1626,
+	}
+	
+	s2 := &gortty.ModemSettings{
+		Baud:       45,
+		StopBits:   2,
+		DataBits:   5,
+		SampleRate: 8000,
+		OneFreq:    2125,
+		ZeroFreq:   2295,
+	}
+
+	portaudio.Initialize()
+	defer portaudio.Terminate()
+
+	in := make([]int16, 64)
+	out := make([]int16, 64)
+
+	stream, err := portaudio.OpenDefaultStream(1, 1, float64(s.SampleRate), len(in), in, out)
+	if err != nil {
+		panic(err)
+	}
+	defer stream.Close()
+	
+	RawDemodulatorIn := make(chan int16)
+	RawDemodulatorOut := make(chan gortty.DCSignal)
+	RawModulatorOut := make(chan int16)
+	
+	gortty.NewRawDemodulator(s, RawDemodulatorIn, RawDemodulatorOut)
+	gortty.NewRawModulator(s2, RawDemodulatorOut, RawModulatorOut)
+
+	stream.Start()
+	
+	go func() {
+		l := 0
+		for v := range RawModulatorOut {
+			out[l] = v
+			l++
+			if l == 64 {
+				l = 0
+				stream.Write()
+			}
+		}
+	}()
+	
+	for {
+		stream.Read()
+		for i := range in {
+			RawDemodulatorIn <- in[i]
+		}
+
+	}
+
+}
+

examples/rttymodem/main.go

@@ -6,7 +6,7 @@ import (
 	"bufio"
 	"bytes"
 	"github.com/gordonklaus/portaudio"
-	"github.com/naleek/openbaudot"
+	"github.com/naleek/gortty"
 	"io"
 	"net"
 	"os"
@@ -24,7 +24,7 @@ func msain() {
 
 func main() {
 	fmt.Println("hi")
-	s := &gobaudot.ModemSettings{
+	s := &gortty.ModemSettings{
 		Baud:       45,
 		StopBits:   2,
 		DataBits:   5,
@@ -43,7 +43,7 @@ func main() {
 		panic(err)
 	}
 	defer stream.Close()
-	charset := gobaudot.LoadCharset(&gobaudot.USTTY)
+	charset := gortty.LoadCharset(&gortty.USTTY)
 
 	encoderIn := make(chan rune, 100)
 	modulatorIn := make(chan byte)
@@ -58,11 +58,11 @@ func main() {
 	modemWriter := NewModemWriter(encoderIn)
 
 	
-	gobaudot.NewEncoder(encoderIn, modulatorIn, charset)
-	modulator := gobaudot.NewModulator(s, modulatorIn, modulatorOut)
+	gortty.NewEncoder(encoderIn, modulatorIn, charset)
+	modulator := gortty.NewModulator(s, modulatorIn, modulatorOut)
 
-	gobaudot.NewDemodulator(s, demodulatorIn, decoderIn)
-	gobaudot.NewDecoder(decoderIn, decoderOut, charset)
+	gortty.NewDemodulator(s, demodulatorIn, decoderIn)
+	gortty.NewDecoder(decoderIn, decoderOut, charset)
 
 	//go CLI(modemReader, modemWriter)
 	modulator.SetAmplitude(0)
@@ -146,7 +146,7 @@ func (m *ModemWriter) Get() rune {
 	return <-m.output
 }
 
-func CLI(ttyReader io.Reader, ttyWriter io.Writer, modulator *gobaudot.Modulator) {
+func CLI(ttyReader io.Reader, ttyWriter io.Writer, modulator *gortty.Modulator) {
 
 	fmt.Fprintln(ttyWriter, "RTTY TCP Modem 1.0")
 

gobaudot_test.go

@@ -1,9 +1,9 @@
-package gobaudot_test
+package gortty_test
 
 import (
 	"testing"
 
-	"github.com/naleek/openbaudot"
+	"github.com/naleek/gortty"
 )
 
 func TestEncoder(t *testing.T) {

modulator.go

@@ -9,7 +9,7 @@
 // the Free Software Foundation; either version 2.1 of the License, or (at
 // your option) any later version.
 
-package gobaudot
+package gortty
 
 import "math"
 

rawdemodulator.go

@@ -0,0 +1,95 @@
+// Copyright (C) 2017 Keelan Lightfoot
+// Copyright (C) 2007-2008 Board of Regents of the University of Wisconsin
+//             System (Univ. of Wisconsin-Madison, Trace R&D Center)
+// Copyright (C) 2007-2008 Omnitor AB
+// Copyright (C) 2007-2008 Voiceriver Inc
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation; either version 2.1 of the License, or (at
+// your option) any later version.
+
+package gortty
+
+import (
+	"math"
+)
+
+
+
+// RawDemodulator is fun
+type RawDemodulator struct {
+	input         chan int16
+	output        chan DCSignal  
+	dsp           *dsp
+	settings      *ModemSettings
+	sigOut        bool
+	samplerate    int
+	div           int
+}
+
+// NewRawDemodulator is fun
+func NewRawDemodulator(s *ModemSettings, input chan int16, output chan DCSignal) *RawDemodulator {
+
+	d := new(RawDemodulator)
+	d.input = input
+	d.output = output
+	
+	d.settings = s
+
+	// the bandpass filter is picky about the sample rate, and the output is perfectly
+	// balanced when the sample rate is 3x the center frequency, so lets divide the sample
+	// rate down to as close to that as we can get.
+
+	centerFrequency := math.Abs(float64(d.settings.OneFreq)+float64(d.settings.ZeroFreq)) / 2 * 3
+
+	d.div = int(math.Floor(float64(d.settings.SampleRate) / float64(centerFrequency)))
+	if d.div == 0 {
+		d.div = 1
+	}
+
+	d.samplerate = d.settings.SampleRate / d.div
+	
+	d.dsp = newDsp(d.settings.OneFreq, d.settings.ZeroFreq, d.samplerate)
+
+	go d.run()
+	return d
+}
+
+func (d *RawDemodulator) run() {
+
+	count := 0
+	for sam := range d.input {
+	
+		// sample rate reduction
+		count++
+		if count%d.div > 0 {
+			continue
+		}
+
+		d.dsp.demod(float64(sam))
+
+		var signal int8
+		var quality int8
+		
+
+		if math.Abs(d.dsp.demLpf) > d.dsp.demTotal*d.dsp.minThresh && d.dsp.demTotal*d.dsp.minThresh != 0 {
+			quality = 1
+		} else {
+			quality = 0
+		}
+
+		if d.dsp.demLpf - d.dsp.minThresh*d.dsp.demTotal > 0 {
+			signal = 1*quality
+		} else {
+			signal = -1*quality
+		}	
+				
+		d.output <-  DCSignal {
+			Signal: signal,
+			Quality: quality,
+		}
+		
+	}
+
+}

rawmodulator.go

@@ -0,0 +1,92 @@
+// Copyright (C) 2017 Keelan Lightfoot
+// Copyright (C) 2007-2008 Board of Regents of the University of Wisconsin
+//             System (Univ. of Wisconsin-Madison, Trace R&D Center)
+// Copyright (C) 2007-2008 Omnitor AB
+// Copyright (C) 2007-2008 Voiceriver Inc
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation; either version 2.1 of the License, or (at
+// your option) any later version.
+
+package gortty
+
+import "math"
+//import "fmt"
+
+type DCSignal struct {
+	Signal int8
+	Quality int8
+}
+
+// RawModulator is fun
+type RawModulator struct {
+	input  chan DCSignal
+	output chan int16
+
+	settings *ModemSettings
+
+	phaseQ16        uint16  // phase acc 0..2math.Pi -> 0..65536
+	amplitude       int16   // peak RawModulator amplitude for one tone
+	wOneQ16         uint16  // scaled one freq 0..2math.Pi -> 0..65536
+	wZeroQ16        uint16  // scaled zero freq 0..2math.Pi -> 0..65536
+	sinLutQ15       []int16 // sine lookup table
+	callback        Callback
+}
+
+// NewRawModulator is fun
+func NewRawModulator(s *ModemSettings, input chan DCSignal, output chan int16) *RawModulator {
+
+	m := new(RawModulator)
+
+	m.input = input
+	m.output = output
+
+	m.settings = s
+
+	m.amplitude = 16384
+
+	wOne, wZero := calculateW(m.settings.OneFreq, m.settings.ZeroFreq, m.settings.SampleRate)
+
+	m.wOneQ16 = uint16((65536 / (2.0 * math.Pi)) * wOne)
+	m.wZeroQ16 = uint16((65536 / (2.0 * math.Pi)) * wZero)
+
+	m.sinLutQ15 = make([]int16, 16384)
+	for i := 0; i < 16384; i++ {
+		m.sinLutQ15[i] = int16(32767 * math.Sin(2.0*math.Pi*float64(i)/float64(16384)))
+	}
+	go m.run()
+	return m
+}
+
+// SetCallback is fun
+func (m *RawModulator) SetCallback(callback Callback) {
+	m.callback = callback
+}
+
+func (m *RawModulator) SetAmplitude(amplitude int16) {
+	m.amplitude = amplitude
+}
+
+func (m *RawModulator) run() {
+
+	var lut uint16
+	for {
+		select {
+		case s := <-m.input:
+			if s.Signal > 0 {
+				lut = m.wOneQ16
+			} else {
+				lut = m.wZeroQ16
+			}
+			m.phaseQ16 += lut
+			if s.Quality > 0 {
+				m.output <- multq15(m.amplitude, m.sinLutQ15[m.phaseQ16>>2])
+			} else {
+				m.output <- 0
+			}
+		}
+		
+	}			
+
+}