Monday, February 20, 2012

Android App - Maximum Data Rate of a Channel


Summary
Code of an Android app to calculate the maximum data rate of a channel according to Shannon and Nyquist.

Description
This tutorial shows the code used to create an Android application.  The application calculates the maximum data rate of a channel.  The two following formulas being used are:

Nyquist
maximum data rate = 2B log2 V
B is bandwidth
V is levels

This is represented by "MaximumDataRates.NyquistMdr(bandwidth, levels)"

Shannon
maximum number of bits/sec = B log2 (1 + S/N)
This is represented by "MaximumDataRates.ShannonMdr(decibels, bandwidth)"
B is bandwidth
S/N is signal-to-noise ratio


This a plain application.  There are three parts to the application:

  1. Writing the MaximumDataRates.java class (static methods)
  2. Writing the MaximumDataRates_AndroidActivity.java (our main, and only, activity)
  3. Writing the main.xml file (res/layout/main.xml) for the presentation of the MaximumDataRates_AndroidActivity.java

Before we begin
For the tutorial, take a look at the following:

Shannon-Hartley theorem (wikipedia) - A more in-depth description.


What do you need to make it work? - When creating a new Android project in Eclipse, all you need to do is  add the package at the top, make sure your activity name.java matches the name used inside the activity.java file, and copy everything in this main.xml to your main.xml.

Any questions? Please ask!

Maximum Data Rate (static methods)



public class MaximumDataRates {

// private no-arg constructor
// driving home the point
private MaximumDataRates(){

}

static double NyquistMdr(double bandwidth, double levels){

return(2 * bandwidth * (Math.log(levels) / Math.log(2)));
}

static double ShannonMdr(double decibels, double bandwidth){

return (bandwidth * Math.log((FindSignalToNoise(decibels) + 1)) / Math.log(2));
}

static double FindSignalToNoise(double decibels){
return Math.pow(10, (decibels / 10));
}


}

MaximumDataRates_AndroidActivity.java



import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.RadioButton;
import android.widget.TextView;


public class MaximumDataRates_AndroidActivity extends Activity {
    /** Called when the activity is first created. */
    
   
    
    // For the Nyquist TextBoxes
    LinearLayout nyquistGroup;
    EditText nyquistBandwidth;
    EditText nyquistLevels;
    TextView nyquistOutput;
    
    
    // For the Shannon TextBoxes
    LinearLayout shannonGroup;
    EditText shannonBandwidth;
    EditText shannonDecibels;
    TextView shannonOutput;
    
    // For the SNR TextBoxes
    LinearLayout convertDecibelsToSnrGroup;
    EditText snrDecibels;
    TextView snrOutput;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        // Nyquist
        nyquistGroup = (LinearLayout)findViewById(R.id.lnlNyquist);
        nyquistBandwidth = (EditText)findViewById(R.id.txtNyquistBandwidth);
        nyquistLevels = (EditText)findViewById(R.id.txtNyquistLevels);
        nyquistOutput = (TextView)findViewById(R.id.lblNyquistOutput);
        
        // Shannon
        shannonGroup = (LinearLayout)findViewById(R.id.lnlShannon);
        shannonBandwidth = (EditText)findViewById(R.id.txtShannonBandwidth);
        shannonDecibels = (EditText)findViewById(R.id.txtShannonDecibels);
        shannonOutput = (TextView)findViewById(R.id.lblShannonOutput);
        
        
        // Convert Decibels to SNR
        convertDecibelsToSnrGroup = (LinearLayout)findViewById(R.id.lnlConvertDecibelToSnr);
        snrDecibels = (EditText)findViewById(R.id.txtSnrDecibels);
        snrOutput = (TextView)findViewById(R.id.lblSnrOutput);
       
        hideAllGroups();
        
        
        
        nyquistGroup.setVisibility(0);
        
        
        
    }
    
    public void radioListener(View view)
    {
    RadioButton rb = (RadioButton) view;
   
    if(rb.getText().toString().equals("Nyquist"))
    {
    hideAllGroups();
    nyquistGroup.setVisibility(0);
    nyquistOutput.setText("");
   
    }
    else if(rb.getText().toString().equals("Shannon"))
    {
    hideAllGroups();
    shannonGroup.setVisibility(0);
    shannonOutput.setText("");
    }
    else if(rb.getText().toString().equals("Decibels to SNR"))
    {
    hideAllGroups();
    convertDecibelsToSnrGroup.setVisibility(0);
    snrOutput.setText("");
    }
   
   
    }
    
    public void calcNyquist(View view)
    {
   
    double bandwidth;
    double levels;
    String result = "";
   
    try{
    bandwidth = Double.parseDouble(nyquistBandwidth.getText().toString());
    levels = Double.parseDouble(nyquistLevels.getText().toString());
   
    result = Double.toString(MaximumDataRates.NyquistMdr(bandwidth, levels));
   
    nyquistOutput.setText(result);
    }
    catch(Exception ex)
    {
    result = "Something is wrong with your input";
    nyquistOutput.setText(result);
    }
    }
    
    public void calcShannon(View view)
    {
    double bandwidth;
    double decibels;
    String result = "";
   
    try{
    bandwidth = Double.parseDouble(shannonBandwidth.getText().toString());
    decibels = Double.parseDouble(shannonDecibels.getText().toString());
   
    result = Double.toString(MaximumDataRates.ShannonMdr(decibels, bandwidth));
   
    shannonOutput.setText(result);
    }
    catch(Exception ex){
    result = "Something is wrong with your input";
    shannonOutput.setText(result);
    }
   
    }
    
    public void convertDecibelToSnr(View view)
    {
    double decibels;
    String result = "";
   
    try{
    decibels = Double.parseDouble(snrDecibels.getText().toString());
    result = Double.toString(MaximumDataRates.FindSignalToNoise(decibels));
   
    snrOutput.setText(result);
    }
    catch(Exception ex)
    {
    result = "Something is wrong with your input";
    snrOutput.setText(result);
    }
   
    }
    
    public void hideAllGroups()
    {
    //outputGroup.setVisibility(0);
    nyquistGroup.setVisibility(8);
    shannonGroup.setVisibility(8);
    convertDecibelsToSnrGroup.setVisibility(8);
   
    }
}

Main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    

    <RadioGroup
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" >
      
    <RadioButton
        android:id="@+id/radNyquist"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="radioListener"
        
        android:text="Nyquist" />
    <RadioButton
        android:id="@+id/radShannon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="radioListener"
        android:text="Shannon" />
    <RadioButton
        android:id="@+id/radConvertDecibelToSnr"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="radioListener"
        android:text="Decibels to SNR" />
    </RadioGroup>
        
    <LinearLayout 
        android:id="@+id/lnlNyquist"
        android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >
    <TextView 
        android:id="@+id/lblNyquistTitle"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Nyquist: MDR=2B log2 V"
        android:gravity="center"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <TextView
        android:id="@+id/lblNyquistBandwidth"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Bandwidth" />

    <EditText
        android:id="@+id/txtNyquistBandwidth"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >

        <requestFocus />
    </EditText>

    <TextView
        android:id="@+id/lblNyquistLevels"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Levels" />

    <EditText
        android:id="@+id/txtNyquistLevels"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />


    <Button
        android:id="@+id/btnNyquistCalculate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="calcNyquist"
        android:text="Calculate" />
    
    <TextView 
        android:id="@+id/label1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Result"
        android:gravity="center"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    
    <TextView
        android:id="@+id/lblNyquistOutput"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="" />
    
    
</LinearLayout>
    
    <LinearLayout 
        android:id="@+id/lnlShannon"
        android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >
    
    <TextView
        android:id="@+id/lblShannonTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Shannon MDR=B log2 (1+SN)"
        android:gravity="center"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <TextView
        android:id="@+id/lblShannonBandwidth"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Bandwidth" />

    <EditText
        android:id="@+id/txtShannonBandwidth"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/lblShannonDecibels"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Decibels" />

    <EditText
        android:id="@+id/txtShannonDecibels"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />


    <Button
        android:id="@+id/btnShannonCalculate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="calcShannon"
        android:text="Calculate" />

    <TextView 
        android:id="@+id/label2"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Result"
        android:gravity="center"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    
    <TextView
        android:id="@+id/lblShannonOutput"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="" />
    
    
    
    </LinearLayout>
    
        <LinearLayout 
        android:id="@+id/lnlConvertDecibelToSnr"
        android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >
    <TextView
        android:id="@+id/lblConvertDecibelToSnrTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Convert Decibel to SNR"
        android:gravity="center"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <TextView
        android:id="@+id/lblSnrDecibels"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Decibels" />

    <EditText
        android:id="@+id/txtSnrDecibels"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />
    
    <Button
        android:id="@+id/btnSnrCalculate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="convertDecibelToSnr"
        android:text="Calculate" />
    <TextView 
        android:id="@+id/label3"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Result"
        android:gravity="center"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
    <TextView
        android:id="@+id/lblSnrOutput"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="" />
</LinearLayout>
    
        
</LinearLayout>

1 comment:

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    Thanks.
    iCaption That

    ReplyDelete