=  NOW 40 WPM  =
CONNECTOR AND YOUR LOADS TO THE REAR PANEL PORTS, AND YOURE READY TO
GO.  THE FRONT PANEL BUTTONS LABELED 1 5 ALLOW YOU TO TURN ON AND
OFF EACH REAR PANEL LOAD PORT.  AN LED FOR EACH PORT INDICATES PORT
STATUS GREEN FOR ON AND UNLIT FOR OFF.  THE LCD DISPLAYS THE OUTPUT
NAME NODE 1 THROUGH NODE 5 BY DEFAULT, BUT YOU CAN RENAME THESE IN
THE WEB INTERFACE SEE FIGURE 9, AS WELL AS THE CURRENT BEING DRAWN
BY THAT LOAD.  YOU CAN CYCLE THROUGH THE STATUS OF EACH PORT ON THE
LCD USING THE MORE ABOUT DSPS THE 100TH EDITION OF THE ARRL HANDBOOK
FOR RADIO COMMUNICATIONS DEVOTES AN ENTIRE CHAPTER CHAPTER 8 TO DSPS
AND THEIR FUNCTIONS.  AMONG THE EXAMPLES INCLUDED ARE SOFTWARE
DEFINED RADIOS SDRS.  THE CHAPTER BEGINS BY POINTING OUT THAT THE
MATHEMATICAL BASIS FOR DIGITAL SIGNAL PROCESSING DATES BACK TO WELL
KNOWN MATHEMATICAL NAMES IN THE 17TH, 18TH, AND 19TH CENTURIES.  IT
WAS NOT UNTIL AFTER THE DIGITAL REVOLUTION IN THE EARLY 1990S, WITH
THE WIDESPREAD AVAILABILITY OF DIGITAL PROCESSING ESPECIALLY FAST
PROCESSING THAT MANY APPLICATIONS MOVED FROM THE THEORETICAL TO THE
PRACTICAL.  THE CHAPTER INCLUDES A FULL PAGE OF REFERENCES AND OTHER
MATERIAL.  THERE ARE ALSO SEVERAL ONLINE FILES SUPPLEMENTING THIS
CHAPTER.  IN THE SAME HANDBOOK EDITION, CHAPTER 10, TITLED ANALOG
AND DIGITAL FILTERING, CONTAINS SEVERAL SECTIONS DEVOTED TO DIGITAL
FILTER DESIGN.  THIS CHAPTER IS SUPPLEMENTED BY MORE THAN A DOZEN
DOWNLOADABLE FILES AND A FULL PAGE OF REFERENCES AND OTHER LISTS OF
HELPFUL MATERIALS.  NEWER APPROACHES, SUCH AS DEEP LEARNING, ARE
ALSO USED TO DESIGN VARIOUS FILTERS.  A DEMONSTRATION OF ONE SUCH
APPROACH IS POSTED BY MATHWORKS AT WWW.  MATHWORKS. COM/ SOLUTIONS/
DEEP LEARNING/ DEEP LEARNING SIGNAL PROCESSING.  HTML.  THEY ALSO
OFFER A FREE ONLINE BOOK ON THE TOPIC.  OTHER NEW APPROACHES CAN BE
FOUND UNDER THE GENERAL TOPIC ARTIFICIAL INTELLIGENCE ON THE WEB.  A
SECOND SET OF TESTS WERE RUN IN THE EVENING ON THE 75 METER PHONE
BAND, WITH THE EXPECTATION THAT THE NOISE SPECTRUM OR OTHER
CHARACTERISTICS WOULD BE DIFFERENT.  THE NOISE LEVEL WAS DIFFERENT,
RUNNING S 6 TO S 7.  THERE WAS GENERALLY NO DIFFERENCE IN
PERFORMANCE.  A FEW STATIONS WERE BARELY DISCERNABLE AT THIS HIGHER
NOISE LEVEL.  SOME COULD BE PULLED OUT BY CHANGING THE DSP FILTER
LEVEL.  OTHER BARELY DISCERNABLE SIGNALS POPPED OUT OF THE NOISE,
BUT THEY WERE UNINTELLIGIBLE.  AT THIS LOCATION, MANY STATIONS ON
THE 75 METER PHONE BAND TEND TO HAVE SIGNAL STRENGTHS OF S 9 PLUS 30
DB SOME OF THE NOISE AROUND THE WEAK STATIONS MAY BE SPLATTER OF
SOME SORT FROM ONE OF THESE STRONG STATIONS.  FINALLY, A NUMBER OF
LISTENING TESTS WERE RUN ON 20 METERS DURING THE DAY.  RESULTS WERE
THE SAME AS ON 40 METERS.  NO S 9 PLUS 30 DB CLOSE STATIONS WERE
ENCOUNTERED ON EITHER 40 OR 20 METERS.  IN SUMMARY THE MOST
INTERESTING CHARACTERISTIC NOTED IN THESE TESTS WAS THAT ON A
WEEKEND AFTERNOON, WHEN THE POTA CONTEST WAS VERY ACTIVE, OPERATION
WAS PRIMARILY HANDS OFF.  THE DSP FILTER LEVEL WAS SET TO 2 AND LEFT
THERE, EXCEPT FOR A
=  END OF 40 WPM TEXT  =  QST DE W1AW  <