AM and FM Transmitters

purplemonkey · 2012-08-10 11:06

Where do you connect to ground with resistors? Do you mean from aerial?

Publison · 2012-08-10 11:09

purplemonkey wrote: »

here you goAttachment not found.

Golly gee. That doesn't sound like 2m_fm_modulation1.spin.

purplemonkey · 2012-08-10 11:14

wonder if my prop chip is fried? but surely if it was i wouldn't be able to program it would i?

Publison · 2012-08-10 11:19

purplemonkey wrote: »

wonder if my prop chip is fried? but surely if it was i wouldn't be able to program it would i?

Go back through the PEK Education Labs, and see if you can blink a LED on each pin. That will tell you if the Propeller is working. Run through the whole lab and you will understand much of what is being discussed here.
'

purplemonkey · 2012-08-10 11:26

Ok, but in the meantime can you see in that file how to change broadcast pin?

Publison · 2012-08-10 11:53

Can you take a guess on the PIN number from this code?

I think it's time to hit the books.

  _clkmode = XTAL1 + PLL16X
  _xinfreq = 5_000_000


  { FFFF_FFFF / (CLKFREQ / (80Mhz / PLL16)) }
  c80mhz = %0001_0000__0000_0000__0000_0000__0000_0000
  { FFFF_FFFF / (CLKFREQ / (100Mhz / PLL16)) }
  c100mhz = %0001_0100__0000_0000__0000_0000__0000_0000
  { FFFF_FFFF / (CLKFREQ / (140Mhz / PLL16)) }
  c140mhz = %0001_1100__0000_0000__0000_0000__0000_0000
  { FFFF_FFFF / (CLKFREQ / 6.550Mhz) }
  c6p550mhz = 351_650_447
  { FFFF_FFFF / (CLKFREQ / 6.500Mhz) }
  c6p500mhz = 348_966_092




PUB Main | cog
  VCFG := %10 << 29 + COGID << 23 + %1000_0000            'set for broadcast aural on pin 7 using this COG


  CTRB:=%00001_111 << 23        'setup the broadcast PLL internal 16x
  FRQB:=c80mhz                 'start the PLL


  PlayWAV                       'play


PUB PlayWAV | p, time, x
  DIRA[7]~~
  CTRA:=%0001_011 << 23         'setup internal PLL 1x


  x:=clkfreq/11025              'sample rate
  repeat
    p := @beback + 44


    time := cnt
    repeat while p++ < @end
      FRQA := c6p500mhz + byte[p] << 14                  'modulate carrier and amplify the sample
      waitcnt(time += x)


    waitcnt(clkfreq + cnt)


DAT


beback byte
File "expectu.wav"
end byte 0

purplemonkey · 2012-08-10 12:05

I'm guessing it's pin 16 or 7 but I tried to change it and kept getting unknown object error

mstram · 2016-04-29 20:27

How are CTRA and CTRB interacting to modulate the (audio) signal ?

Is it just the fact that they are both using the same transmit pin ?

AM and FM Transmitters

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