Editing Simulation example: FSK

Jump to: navigation, search

Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.

The edit can be undone. Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.
Latest revision Your text
Line 26: Line 26:
 
The repeat factor is (int)(samp_rate*0.022)
 
The repeat factor is (int)(samp_rate*0.022)
  
For this flowgraph, the standard RTTY (radioteletype) tones of 2295Hz (Mark=1) and 2125Hz (Space=0) are generated by the VCO. The calculations for this follow:
+
For this flowgraph, the standard RTTY (radioteletype) tones of 2295 (Mark=1) and 2125 (Space=0) are generated by the VCO. The calculations for this follow:
  
* Choosing a full-scale frequency of 2500Hz (vco_max) for an input of +1, the VCO Sensitivity = (2 * Pi * 2500 / 1) = 15708   Any frequency greater than 2295Hz could be used. 2500Hz is a nice round number.
+
* Choosing a full-scale frequency of 2500Hz (vco_max) with an input of +1, the VCO Sensitivity = (2 * Pi * 2500 / 1) = 15708
* Looking at the output of the Low Pass Filter, a Mark = +1.0 and a Space = 0.0
+
* The Space frequency of 2125 is created by vco_offset = (2125 / 2500) = 0.850
* The Space frequency of 2125Hz is created by vco_offset = (2125 / 2500) = 0.850 + (0.0 * 0.068)
+
* The Mark frequency of 2295 is created by a vector of inp_amp = (1 * 0.068) + vco_offset = 0.918
* The Mark frequency of 2295Hz is created by a vector of inp_amp = (1.0 * 0.068) + vco_offset = 0.918 (2295/2500)
 
  
 
The Frequency Xlating FIR Filter taps parameter is 'firdes.low_pass(1.0,samp_rate,1000,400)'. Note that the desired signal has a deviation of 170Hz. so this filter rejects adjacent channel signals.
 
The Frequency Xlating FIR Filter taps parameter is 'firdes.low_pass(1.0,samp_rate,1000,400)'. Note that the desired signal has a deviation of 170Hz. so this filter rejects adjacent channel signals.

Please note that all contributions to GNU Radio are considered to be released under the Creative Commons Attribution-ShareAlike (see GNU Radio:Copyrights for details). If you do not want your writing to be edited mercilessly and redistributed at will, then do not submit it here.
You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource. Do not submit copyrighted work without permission!

To edit this page, please answer the question that appears below (more info):

Cancel | Editing help (opens in new window)