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???
12/15/08 19:47
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 		 #160964 - I have no such problem
Responding to: ???'s previous message
The power supply may produce intensity modulation from the 60Hz that gives similar interference as if running the display close to fluorescent lights. There are so many strange things that can vary even in a trivial test, that may somehow affect the tested persons. The last factor I mention - 60Hz modulation of the DC powering the diodes - is a very important factor since it not only explains why people can see close to 120 Hz refresh but should be applicable in real-life to a lot of fixed installations. In this case, you then found one of two possible solutions to the problem.
our signs run on 24V DC lead-acid, diesel charged

Erik


List of 60 messages in thread
TopicAuthorDate
Help Req:Working of 8-bit SIPO Shift Register in LED Display            01/01/70 00:00      
   Look at some datasheets?            01/01/70 00:00      
      Sequence            01/01/70 00:00      
   Could you be more specific?            01/01/70 00:00      
      Got U!            01/01/70 00:00      
         New thread            01/01/70 00:00      
            OK...but            01/01/70 00:00      
               You just proved the point!            01/01/70 00:00      
               Here is a possible solution            01/01/70 00:00      
                  Rash assumption?            01/01/70 00:00      
                     you can use MPUs those has built-in flash            01/01/70 00:00      
                  EPROM with AT89S52            01/01/70 00:00      
               permanent?            01/01/70 00:00      
                  No....            01/01/70 00:00      
                     Non-Volatile Storage            01/01/70 00:00      
                        Still a Problem            01/01/70 00:00      
                           Obviously            01/01/70 00:00      
                              Design work before chip selection            01/01/70 00:00      
         What about LED drive current?            01/01/70 00:00      
            if you plan to multiplex ....            01/01/70 00:00      
               I know you're well versed in this context ...            01/01/70 00:00      
                  Phosphor persistence?            01/01/70 00:00      
                     That's in Erik's primary domain            01/01/70 00:00      
                        Todays LEDs turn on and off very fast            01/01/70 00:00      
                           Intermodulation            01/01/70 00:00      
                              you make some additional points, but            01/01/70 00:00      
                           But what about TV?            01/01/70 00:00      
                              persistence of the tube, I guess            01/01/70 00:00      
                                 Blind test?            01/01/70 00:00      
                                    Problematic test strategy            01/01/70 00:00      
                                       double blind ?            01/01/70 00:00      
                                          Blind tests, revisited            01/01/70 00:00      
                                             I have no such problem            01/01/70 00:00      
                                                For flimmer test too?            01/01/70 00:00      
                                                   done inside and outside            01/01/70 00:00      
                  Interlace            01/01/70 00:00      
                     Not Really            01/01/70 00:00      
               Maybe skip intensity and on-the-fly updates            01/01/70 00:00      
                  They haven not been discussed ... yet            01/01/70 00:00      
                     Forget All...........            01/01/70 00:00      
                        Don't you need a refresh memory?            01/01/70 00:00      
                        Table Lookup is Used            01/01/70 00:00      
                        Need buffering            01/01/70 00:00      
                        that is ridiculous            01/01/70 00:00      
                           character generation            01/01/70 00:00      
                              i think you got me...            01/01/70 00:00      
                                 No tricks involved            01/01/70 00:00      
                                 Here's one way ... but you'll have to code it yourself            01/01/70 00:00      
                                    thanks...i'll try it            01/01/70 00:00      
                                       how to reset HEF4094            01/01/70 00:00      
                                          difference between "strobe" and "output enable" pins?            01/01/70 00:00      
                                          Only be serially writing zeros to it...            01/01/70 00:00      
                                          How are you using the '4094?            01/01/70 00:00      
                                             Not so simple for a newbie...            01/01/70 00:00      
                                                perhaps you're right, Kai            01/01/70 00:00      
                                                   Thanks, but            01/01/70 00:00      
                                                      Did you even read the prior posts?            01/01/70 00:00      
                                                         multiple parallel outputs            01/01/70 00:00      
                                                            actually, yes!            01/01/70 00:00      
   Telephonic discussion            01/01/70 00:00      

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