Re: Where did the modulation go . . .


ab9ca@...
 


OK, you are speaking a language I do not understand. I don't know what BCM is nor where to find it. I don't know what pinout.xyz is nor where to find it. Maybe if we use the 40 pin header we can both recognize which pin we are talking about?


So far as I know there is nothing else running on the RPi.  But I can no longer recall how to display what is running. Years ago I ran Linux full time. But have forgotten much of it. 


The new tone generation script does not work. I get the following:

..........................

pi@compass:~ $ ./measure_deviate.sh -f 1000 -c din6 -l 180

./measure_deviate.sh: line 5: syntax error near unexpected token `newline'

./measure_deviate.sh: line 5: `<!DOCTYPE html>'

..........................................

However I still have the old script that does work, AFAIK. I renamed it 'generate_tone.sh'. The following command should generate 1000 cycle tone for 3 min:

................................. 
pi@compass:~ $ ./generate_tone.sh 1000 10
Found existing wav file: 1000hzsin.wav
If using devcal from Svxlink make sure devcal line has -f1000
Using PTT GPIO 23 with tone of 1000 Hz
Playing WAVE '1000hzsin.wav' : Signed 32 bit Little Endian, Rate 48000 Hz, Stereo
Hardware PCM card 0 'udrc' device 0 subdevice 0
Its setup is:
  stream       : PLAYBACK
  access       : RW_INTERLEAVED
  format       : S32_LE
  subformat    : STD
  channels     : 2
  rate         : 48000
  exact rate   : 48000 (48000/1)
  msbits       : 32
  buffer_size  : 24000
  period_size  : 6000
  period_time  : 125000
  tstamp_mode  : NONE
  period_step  : 1
  avail_min    : 6000
  period_event : 0
  start_threshold  : 24000
  stop_threshold   : 24000
  silence_threshold: 0
  silence_size : 0
  boundary     : 1572864000
  appl_ptr     : 0
  hw_ptr       : 0
##################################################+| MAX^C
...............................................

While this command is running I see the following on these pins of the 40 pin header:

pin 3 - a DC voltage of about 3.4v, no waveform
pin 5 - a DC voltage of about 3.4v, no waveform
pin 7 - nothing, no DC nor waveform
pin 12 - apprx 3.4v rectangular wave at approx 3 MHz

pin 35 - rectangular wave approx 3.4v approx 48 kHz

pin 38 -  nothing

pin 40 - a pulse width modulated 3.4 v rectangular waveform


This command should cause the RPi to generate a 1000 Hz tone and send it to din 6. It does not do so. 

Should there not be the master clock on pin 7? 


I don;t think the I2C is used by this script so I can understand no activity on pins 2 and 3.


What next?


73, dave

ab9ca/4


Join udrc@nw-digital-radio.groups.io to automatically receive all group messages.