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volib TDU question

Jeff Brower73
Genius 3420 points

We're running tone test data through the volib TDU (digits_plus_dialtone.pcm = 2 sec, 48 tones).  For each tone we see callbacks from tduSendIn() with

  event = ALERT ON, time = 15 msec
  event = ON, time = 30 msec
  event = OFF, time = 20 msec

1) We assume that tduSendIn() is not making a callback if there is no change in state, so the above sequence implies transition (OFF to ALERT ON, ALERT ON to ON, and ON to OFF).  Please confirm.

2) We're not sure how to interpret the returned time values.  How should we calculate the total tone duration?

Jeff Brower
Signalogic

  • 0
    TI__Guru* 95265 points

    Jeff,

    C:\ti\volib_C66_2_1_0_1\packages\ti\mas\tdu\test\vectors\inp\digits_plus_dialtone.pcm is 1.6 seconds with 16 tones inside. What file are your referring to?

    Regards, Eric

  • 0 in reply to lding
    Genius 3420 points

    Eric-

    Yes 16 tones, 1.6 sec.  When I discussed with engineering, I got confused -- they said "48 events", not tones.  So yes 16 tones, 3 events each.  My apologies.

    -Jeff

  • 0 in reply to Jeff Brower73
    TI__Guru* 95265 points

    Jeff,

    The printed time in ms is misleading, but the frame is reliable.

      Digit: "1"     :  Event: ALERT  ON,  Time:   20 ms,  Power: -83 dBm0,  Frame: 1544
      Digit: "1"     :  Event:  ON,  Time:   30 ms,  Power: -10 dBm0,  Frame: 1547
      Digit: "1"     :  Event: OFF,  Time:   20 ms,  Power: -567 dBm0,  Frame: 1554

    In above exmaple, the first Frame is where an DTMF early detection is ON. The second Frame is where the DTMF is confirmed ON, the third is DTMF OFF. Each frame is 5 ms. So, the DTMF duration is 1554-1547=7 frames, or 35 ms.

    Regards, Eric

     

  • 0 in reply to lding
    Genius 3420 points

    Eric-

    Ok thanks.  We'll use this method.

    -Jeff