Can it act as a PLL?
Martin Hebel
Posts: 1,239
Hi all,
My higher engineering skills aren't all that hot, but we have need to be able to perform some frequency descrimination for an underwater communications device we are working on.· Essentially, using 2 frequency FSK for a data carrier (high/low freq).· The bode plot example made me wonder how that would work for a tone decoder style Phase lock loop?· I'm looking for low power consumption for extended underwater operation with minimal extrnal components.· Even if it wakes up every 15 seconds or so to look for a signal and go back to idle for a low duty cycle would be great.
The propeller is a contridiction in itself.· 95% is so much simplified from a normal controller with all the dedicated HW peripherals and control registers, even though the 8 processors add so much power.· Then there's·dual 2 counters that are far more complex, though far more useful, than a standard controller's counters.
I think·the counter·will be 90% of the battle on developing high level communications applications.
Thanks,
Martin
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Martin Hebel
Southern Illinois University Carbondale - Electronic Systems Technologies
Personal Links with plenty of BASIC Stamp info
StampPlot - Graphical Data Acquisition and Control
My higher engineering skills aren't all that hot, but we have need to be able to perform some frequency descrimination for an underwater communications device we are working on.· Essentially, using 2 frequency FSK for a data carrier (high/low freq).· The bode plot example made me wonder how that would work for a tone decoder style Phase lock loop?· I'm looking for low power consumption for extended underwater operation with minimal extrnal components.· Even if it wakes up every 15 seconds or so to look for a signal and go back to idle for a low duty cycle would be great.
The propeller is a contridiction in itself.· 95% is so much simplified from a normal controller with all the dedicated HW peripherals and control registers, even though the 8 processors add so much power.· Then there's·dual 2 counters that are far more complex, though far more useful, than a standard controller's counters.
I think·the counter·will be 90% of the battle on developing high level communications applications.
Thanks,
Martin
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Martin Hebel
Southern Illinois University Carbondale - Electronic Systems Technologies
Personal Links with plenty of BASIC Stamp info
StampPlot - Graphical Data Acquisition and Control
Comments
I think you should be able to use the two counters to perform a phase detection to determine if a frequency was present. A small modification or direct use of Paul Bakers COUNT routine
might do what you want.
What are the 2 frequencies you are using?
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
-Martin
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Martin Hebel
Southern Illinois University Carbondale - Electronic Systems Technologies
Personal Links with plenty of BASIC Stamp info
StampPlot - Graphical Data Acquisition and Control
and use a low pass filter set at 10Khz ... The presence of 195kHz should produce nothing on the output while
the presence of a 205Khz signal should produce an audible 10KHz signal that might be easier to manipulate.
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.