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swhardenswharden
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working FFT
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‎src/ConsoleDemo/App.config

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<?xml version="1.0" encoding="utf-8" ?>
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<configuration>
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<startup>
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<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
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</startup>
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</configuration>

‎src/ConsoleDemo/ConsoleDemo.csproj

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<?xml version="1.0" encoding="utf-8"?>
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<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
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<Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
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<PropertyGroup>
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<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
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<Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
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<ProjectGuid>{DA5009A8-9036-4BDA-B591-3244DEB759E9}</ProjectGuid>
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<OutputType>WinExe</OutputType>
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<RootNamespace>ConsoleDemo</RootNamespace>
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<AssemblyName>ConsoleDemo</AssemblyName>
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<TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
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<FileAlignment>512</FileAlignment>
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<Deterministic>true</Deterministic>
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</PropertyGroup>
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<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
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<PlatformTarget>AnyCPU</PlatformTarget>
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<DebugSymbols>true</DebugSymbols>
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<DebugType>full</DebugType>
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<Optimize>false</Optimize>
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<OutputPath>bin\Debug\</OutputPath>
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<DefineConstants>DEBUG;TRACE</DefineConstants>
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<ErrorReport>prompt</ErrorReport>
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<WarningLevel>4</WarningLevel>
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</PropertyGroup>
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<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
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<PlatformTarget>AnyCPU</PlatformTarget>
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<DebugType>pdbonly</DebugType>
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<Optimize>true</Optimize>
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<OutputPath>bin\Release\</OutputPath>
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<DefineConstants>TRACE</DefineConstants>
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<ErrorReport>prompt</ErrorReport>
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<WarningLevel>4</WarningLevel>
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</PropertyGroup>
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<PropertyGroup>
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<StartupObject />
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</PropertyGroup>
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<ItemGroup>
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<Reference Include="System" />
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<Reference Include="System.Core" />
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<Reference Include="System.Xml.Linq" />
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<Reference Include="System.Data.DataSetExtensions" />
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<Reference Include="Microsoft.CSharp" />
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<Reference Include="System.Data" />
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<Reference Include="System.Net.Http" />
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<Reference Include="System.Xml" />
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</ItemGroup>
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<ItemGroup>
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<Compile Include="Program.cs" />
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<Compile Include="Properties\AssemblyInfo.cs" />
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</ItemGroup>
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<ItemGroup>
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<None Include="App.config" />
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</ItemGroup>
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<ItemGroup>
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<ProjectReference Include="..\Spectrogram\Spectrogram.csproj">
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<Project>{f4814553-c114-4df7-b0f7-6512796247c7}</Project>
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<Name>Spectrogram</Name>
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</ProjectReference>
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</ItemGroup>
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<Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
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</Project>

‎src/ConsoleDemo/Program.cs

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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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namespace ConsoleDemo
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{
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class Program
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{
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static void Main(string[] args)
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{
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double[] values = Spectrogram.Tools.generateFakeSignal();
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double[] fft = Spectrogram.Tools.FFT(values);
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Spectrogram.Tools.plotValues(values);
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Spectrogram.Tools.plotFFT(fft);
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Console.WriteLine("DONE");
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}
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}
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}

‎src/ConsoleDemo/Properties/AssemblyInfo.cs

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using System.Reflection;
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using System.Runtime.CompilerServices;
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using System.Runtime.InteropServices;
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// General Information about an assembly is controlled through the following
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// set of attributes. Change these attribute values to modify the information
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// associated with an assembly.
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[assembly: AssemblyTitle("ConsoleDemo")]
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[assembly: AssemblyDescription("")]
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[assembly: AssemblyConfiguration("")]
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[assembly: AssemblyCompany("")]
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[assembly: AssemblyProduct("ConsoleDemo")]
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[assembly: AssemblyCopyright("Copyright © 2019")]
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[assembly: AssemblyTrademark("")]
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[assembly: AssemblyCulture("")]
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// Setting ComVisible to false makes the types in this assembly not visible
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// to COM components. If you need to access a type in this assembly from
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// COM, set the ComVisible attribute to true on that type.
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[assembly: ComVisible(false)]
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// The following GUID is for the ID of the typelib if this project is exposed to COM
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[assembly: Guid("da5009a8-9036-4bda-b591-3244deb759e9")]
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// Version information for an assembly consists of the following four values:
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//
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// Major Version
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// Minor Version
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// Build Number
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// Revision
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//
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// You can specify all the values or you can default the Build and Revision Numbers
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// by using the '*' as shown below:
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// [assembly: AssemblyVersion("1.0.*")]
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[assembly: AssemblyVersion("1.0.0.0")]
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[assembly: AssemblyFileVersion("1.0.0.0")]

‎src/Spectrogram/Properties/AssemblyInfo.cs

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using System.Reflection;
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using System.Runtime.CompilerServices;
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using System.Runtime.InteropServices;
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// General Information about an assembly is controlled through the following
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// set of attributes. Change these attribute values to modify the information
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// associated with an assembly.
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[assembly: AssemblyTitle("Spectrogram")]
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[assembly: AssemblyDescription("")]
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[assembly: AssemblyConfiguration("")]
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[assembly: AssemblyCompany("")]
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[assembly: AssemblyProduct("Spectrogram")]
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[assembly: AssemblyCopyright("Copyright © 2019")]
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[assembly: AssemblyTrademark("")]
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[assembly: AssemblyCulture("")]
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// Setting ComVisible to false makes the types in this assembly not visible
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// to COM components. If you need to access a type in this assembly from
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// COM, set the ComVisible attribute to true on that type.
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[assembly: ComVisible(false)]
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// The following GUID is for the ID of the typelib if this project is exposed to COM
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[assembly: Guid("f4814553-c114-4df7-b0f7-6512796247c7")]
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// Version information for an assembly consists of the following four values:
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//
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// Major Version
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// Minor Version
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// Build Number
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// Revision
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//
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// You can specify all the values or you can default the Build and Revision Numbers
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// by using the '*' as shown below:
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// [assembly: AssemblyVersion("1.0.*")]
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[assembly: AssemblyVersion("1.0.0.0")]
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[assembly: AssemblyFileVersion("1.0.0.0")]

‎src/Spectrogram/Spectrogram.cs

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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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namespace Spectrogram
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{
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public class Spectrogram
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{
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}
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}

‎src/Spectrogram/Spectrogram.csproj

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<?xml version="1.0" encoding="utf-8"?>
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<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
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<Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
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<PropertyGroup>
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<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
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<Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
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<ProjectGuid>{F4814553-C114-4DF7-B0F7-6512796247C7}</ProjectGuid>
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<OutputType>Library</OutputType>
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<AppDesignerFolder>Properties</AppDesignerFolder>
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<RootNamespace>Spectrogram</RootNamespace>
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<AssemblyName>Spectrogram</AssemblyName>
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<TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
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<FileAlignment>512</FileAlignment>
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<Deterministic>true</Deterministic>
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</PropertyGroup>
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<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
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<DebugSymbols>true</DebugSymbols>
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<DebugType>full</DebugType>
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<Optimize>false</Optimize>
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<OutputPath>bin\Debug\</OutputPath>
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<DefineConstants>DEBUG;TRACE</DefineConstants>
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<ErrorReport>prompt</ErrorReport>
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<WarningLevel>4</WarningLevel>
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</PropertyGroup>
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<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
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<DebugType>pdbonly</DebugType>
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<Optimize>true</Optimize>
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<OutputPath>bin\Release\</OutputPath>
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<DefineConstants>TRACE</DefineConstants>
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<ErrorReport>prompt</ErrorReport>
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<WarningLevel>4</WarningLevel>
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</PropertyGroup>
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<ItemGroup>
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<Reference Include="NAudio, Version=1.9.0.0, Culture=neutral, processorArchitecture=MSIL">
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<HintPath>..\packages\NAudio.1.9.0\lib\net35\NAudio.dll</HintPath>
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</Reference>
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<Reference Include="ScottPlot, Version=3.0.8.0, Culture=neutral, processorArchitecture=MSIL">
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<HintPath>..\packages\ScottPlot.3.0.9\lib\net45\ScottPlot.dll</HintPath>
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</Reference>
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<Reference Include="System" />
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<Reference Include="System.Core" />
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<Reference Include="System.Drawing" />
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<Reference Include="System.Windows.Forms" />
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<Reference Include="System.Xml.Linq" />
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<Reference Include="System.Data.DataSetExtensions" />
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<Reference Include="Microsoft.CSharp" />
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<Reference Include="System.Data" />
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<Reference Include="System.Net.Http" />
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<Reference Include="System.Xml" />
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</ItemGroup>
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<ItemGroup>
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<Compile Include="Spectrogram.cs" />
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<Compile Include="Properties\AssemblyInfo.cs" />
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<Compile Include="Tools.cs" />
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</ItemGroup>
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<ItemGroup>
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<None Include="packages.config" />
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</ItemGroup>
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<Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
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</Project>

‎src/Spectrogram/Tools.cs

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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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namespace Spectrogram
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{
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public static class Tools
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{
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public static double[] FFT(double[] values, bool useHammingWindow = true)
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{
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int fftSize = 0;
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for (int i = 4; i < 20; i++)
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{
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int potentialFftSize = (int)Math.Pow(2, i);
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if (potentialFftSize <= values.Length)
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fftSize = potentialFftSize;
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else
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break;
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}
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Console.WriteLine($"Processing FFT (size: {fftSize}) of values (size: {values.Length})");
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NAudio.Dsp.Complex[] fft_buffer = new NAudio.Dsp.Complex[fftSize];
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for (int i = 0; i < fftSize; i++)
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{
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fft_buffer[i].X = (float)values[i];
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fft_buffer[i].Y = 0;
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if (useHammingWindow)
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fft_buffer[i].X *= (float)NAudio.Dsp.FastFourierTransform.HammingWindow(i, fftSize);
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}
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// perform the FFT
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NAudio.Dsp.FastFourierTransform.FFT(true, (int)Math.Log(fftSize, 2.0), fft_buffer);
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// a list with FFT values
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double[] fft = new double[fftSize / 2];
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for (int i = 0; i < fft.Length; i++)
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{
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// should this be sqrt(X^2+Y^2)? log10?
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var fftPointLeft = fft_buffer[i];
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var fftPointRight = fft_buffer[fft_buffer.Length - i - 1];
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fft[i] = 0;
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fft[i] += (double)fftPointLeft.X + (double)fftPointLeft.Y;
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fft[i] += (double)fftPointRight.X + (double)fftPointRight.Y;
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fft[i] /= 2;
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fft[i] = Math.Abs(fft[i]);
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}
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return fft;
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}
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public static void plotValues(double[] values, string saveFilePath = "values.png", int sampleRateHz = 8000)
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{
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var plt = new ScottPlot.Plot();
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plt.PlotSignal(values, sampleRateHz, markerSize: 0, lineWidth: 2);
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plt.Title("Signal");
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plt.YLabel("Value");
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plt.XLabel("Time (sec)");
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plt.AxisAuto(0);
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plt.SaveFig(saveFilePath);
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Console.WriteLine($"Saved: {System.IO.Path.GetFullPath(saveFilePath)}");
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}
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public static void plotFFT(double[] fft, string saveFilePath = "fft.png", int sampleRateHz = 8000)
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{
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var plt = new ScottPlot.Plot();
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double fftSampleRate = (double)fft.Length / sampleRateHz * 2;
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plt.PlotSignal(fft, fftSampleRate, markerSize: 0, lineWidth: 2);
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plt.Title("FFT");
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plt.YLabel("Power");
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plt.XLabel("Frequency (Hz)");
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plt.AxisAuto(0);
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plt.SaveFig(saveFilePath);
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Console.WriteLine($"Saved: {System.IO.Path.GetFullPath(saveFilePath)}");
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}
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public static double[] generateFakeSignal(double durationSeconds = 1, int sampleRateHz = 8000, double signalFrequencyHz = 2000)
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{
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int pointCount = (int)(durationSeconds * sampleRateHz);
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double[] values = new double[pointCount];
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// create a sine wave
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double oscillations = signalFrequencyHz * durationSeconds;
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for (int i = 0; i < values.Length; i++)
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values[i] = Math.Sin(((double)i / values.Length) * 2 * Math.PI * oscillations);
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// add noise
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Random rand = new Random();
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for (int i = 0; i < values.Length; i++)
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values[i] += (rand.NextDouble() - .5) * .1;
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return values;
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}
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}
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}

‎src/Spectrogram/packages.config

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<?xml version="1.0" encoding="utf-8"?>
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<packages>
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<package id="NAudio" version="1.9.0" targetFramework="net45" />
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<package id="ScottPlot" version="3.0.9" targetFramework="net45" />
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</packages>

‎src/SpectrographStuff.sln

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Microsoft Visual Studio Solution File, Format Version 12.00
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# Visual Studio Version 16
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VisualStudioVersion = 16.0.29209.62
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MinimumVisualStudioVersion = 10.0.40219.1
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Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ConsoleDemo", "ConsoleDemo\ConsoleDemo.csproj", "{DA5009A8-9036-4BDA-B591-3244DEB759E9}"
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EndProject
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Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Spectrogram", "Spectrogram\Spectrogram.csproj", "{F4814553-C114-4DF7-B0F7-6512796247C7}"
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EndProject
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Global
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GlobalSection(SolutionConfigurationPlatforms) = preSolution
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Debug|Any CPU = Debug|Any CPU
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Release|Any CPU = Release|Any CPU
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EndGlobalSection
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GlobalSection(ProjectConfigurationPlatforms) = postSolution
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{DA5009A8-9036-4BDA-B591-3244DEB759E9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
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{DA5009A8-9036-4BDA-B591-3244DEB759E9}.Debug|Any CPU.Build.0 = Debug|Any CPU
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{DA5009A8-9036-4BDA-B591-3244DEB759E9}.Release|Any CPU.ActiveCfg = Release|Any CPU
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{DA5009A8-9036-4BDA-B591-3244DEB759E9}.Release|Any CPU.Build.0 = Release|Any CPU
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{F4814553-C114-4DF7-B0F7-6512796247C7}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
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{F4814553-C114-4DF7-B0F7-6512796247C7}.Debug|Any CPU.Build.0 = Debug|Any CPU
22+
{F4814553-C114-4DF7-B0F7-6512796247C7}.Release|Any CPU.ActiveCfg = Release|Any CPU
23+
{F4814553-C114-4DF7-B0F7-6512796247C7}.Release|Any CPU.Build.0 = Release|Any CPU
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EndGlobalSection
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GlobalSection(SolutionProperties) = preSolution
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HideSolutionNode = FALSE
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EndGlobalSection
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GlobalSection(ExtensibilityGlobals) = postSolution
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SolutionGuid = {7D18DDFF-2D40-4E8A-9EA7-3F7B658062D3}
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EndGlobalSection
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EndGlobal

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