[Tinyos-help] Acoustic Localization

[Muhammad Azhar]

Hi,
 
(Using T1.1.15, micaz)
 
   With regards to the implementation of acoustic localization by Vanderbilt University, I have some queries pertaining to certain issues:
 
- In OutsideRangingSensorM, the processing (i.e. filtering) is done after AcousticMultiSampler.ReceiveDone() is signalled.
  Thus, does it mean that the buffer array, which consists of a maximum of 850 samples, contains the samples of all 16 chirps before filtering is done?
 
- In AcousticMultiSamplerM, when calling MicADC.getContinuousData(), what is the frequency of data that is sampled for 1 chirp approximately?
  I see that 1 jiffy = 1/32768 s.
  Thus, since rate is set to 100, Timer.fired() would be signalled after every 100/32768 s.
  Therefore, since the "longest" silence + chirp period is 27, MicADC.getContinuousData() would return the greatest number of samples for a single chirp within 2700/32768 s.
  (By the way, BUFFER_LENGTH was defined to be 850 - how was this derived?)
  However, I'm still clueless on the sampling frequency of MicADC.getContinuousData().
 
[FYI - I read through AcousticMultiSampler.txt where it was mentioned that "upon receiving an acoustic beacon message, this component (AcousticMultiSampler) will turn off the radio and will sample the microphone at specified time intervals at around 16 KHz", but I still do not have any idea how these values are derived.]
 
 
  Your help would be very much appreciated. Thanks.
 
Regards,
Azhar
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