INTRODUCTION

ANALOG COMMUNICATION

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The easiest way to explain how to use J-Dsp for analog communication is to work through a simple example. 
Start the J-DSP editor. It may take 30 seconds to download the program and a few more seconds to establish the first block but once the first block is established, the program should run quickly.  Adjust the size of the J-Dsp editor window so that you are still able to read this text or make a printout of this page.

Move the mouse to the left part of the J-Dsp editor and choose Analog comm. on pop down menu. Press Cont. SigGen button on the top part of the window. Move the mouse to the center of the window and push the left mouse button.  You have created a continuous signal generator box.  Similarly, create a DSB-SC AM, Channel, Coherent Detec and Demod box and note that boxes can not be placed on top of one another.  Your editor window should now look like the following: 

Now, connect the box to the Output box so that your editor window looks like the following 

Next, we choose our input signal. Double click inside the Cont. SigGen box and a dialog window appears. If you do not see a dialog window, you are using an older Internet browser and must download the newest version of Netscape Navigator and start over. 
On the right side of the signal generator window, you can see a preview of the signal. You may change the name of the signal, the gain, the time duration, the frequency and sampling frequency by typing the desired value into the appropriate box. The signal type can be changed by clicking on the pop down menu and selecting a signal. 

On the right, you can see a preview of the input signal. Create a sinusoid having time duration from 0 to 30 ms and amplitude 1as shown in the figure below and give the box a name. When all of the parameters have been entered, press the update button to update the signal preview and remember that whenever changes are made to this box, the update button must be pressed in order for the changes to take effect. 

When you click Help button on the dialog window, you can get the information about this block.

Now push "Close" and the dialog window closes. 

Next, we double click inside the DSB-SC AM box and a dialog window appears. On the right side of the DSB-SC AM dialog window, you can see a preview of the signal. You may change the name of the modulated signal, the gain, the carrier frequency, the carrier phase and the sampling frequency by typing the desired value into the appropriate box. Clicking on the pop down menu and selecting a type of output signal can change the output plot. 

Now push "Close" and the dialog window closes. 

Next, we double click inside the Channel box and a dialog window appears. You may change noise power on AWGN channel by typing the desired value into the appropriate box. 

Now push "Close" and the dialog window closes. 

Next, we double click inside the Coherent Detec box and a dialog window appears. You may change the estimated carrier phase by typing the desired value into the appropriate box. 

When you click Help button, you can get the information about this block.

Now push "Close" and the dialog window closes. 

Next, we double click inside the Demod box and a dialog window appears. You may change the name and the bandwidth of low-pass fiter by typing the desired value into the appropriate box. 

When you click Help button, you can get the information about this block.

Now push "Close" and the dialog window closes. 

This concludes the introduction to the J-Dsp editor.