Mission Statement - De-Spinning the Pro-Taser Propaganda

Yeah right, 'Excited Delirium' my ass...

-------------------------------------------------------------------------

The primary purpose of this blog is to provide an outlet for my observations and analysis about tasers, taser "associated" deaths, and the behaviour exhibited by the management, employees and minions of Taser International. In general, everything is linked back to external sources, often via previous posts on the same topic, so that readers can fact-check to their heart's content. This blog was started in late-2007 when Canadians were enraged by the taser death of Robert Dziekanski and four others in a short three month period. The cocky attitude exhibited by the Taser International spokespuppet, and his preposterous proposal that Mr. Dziekanski coincidentally died of "excited delirium" at the time of his taser-death, led me to choose the blog name I did and provides my motivation. I have zero financial ties to this issue.

Saturday, March 7, 2009

The 50,000-to-1 Duration Discrepancy

Taser claims that "that the duration of the shock is only 100 microseconds, which is too short a period to stimulate the heart." [LINK]


The above claim (dating from 2006) may possibly be true for the older 1999-era M26 taser.

But I do not believe that it remains true for the newer X26 taser introduced in 2003.

I've already described the logic behind my position many times in this blog. [LINK]

The basic point is that Taser introduced a significant change to the waveform shape between the older 1999-era M26 and the newer 2003-era X26. See [LINK] [LINK] and [LINK].

The critical change is the addition of deceptively-small-looking monophasic (DC) pulse emitted after the arc phase at the 19Hz pulse repetition frequency (PRF). The effect of this DC-offset pulse is that it causes the output current waveform spectrum to contain possibly-significant amounts of more-dangerous low frequency energy at the PRF of 19Hz and all related harmonics (38Hz, 57Hz, 76Hz, etc.)


And here's the punchline: Those low frequency spectral components are continuous 100% duty cycle for the entire 5-second deployment cycle. See [LINK].

In other words, their duration is five seconds for a normal single deployment cycle.

It's only the high frequency components, at 100kHz, which are the very short 100 microseconds duration.

Guesstimated Spectrograms [LINK]

Five seconds is 50,000 times longer than 100 microseconds.

And that's assuming a single deployment cycle. Mr. Dziekanski suffered five cycles reportedly totalling about 31 seconds.

These low frequency spectral components with a duration some fifty-thousand times longer than has been acknowledged anywhere that I have seen.


It must be noted that Taser reduced the peak output current from 18 amps peak (18A!, not a typo) on the older M26 taser, to about 3 amps peak (3A!, not a typo) on the X26. So that's about a six-to-one ratio climb down of peak current. Small potatoes compared to 50,000.


Not to mention that low frequencies like 19Hz and related harmonics are the more dangerous low frequency (low frequency is considered to be somewhat less dangerous than high frequency).


Overall, I suspect that the X26 is more lethal than expected because it appears that Taser Forgot Fourier.

Forgetting Fourier are we ? [LINK]


Has anyone compared the actual street level death rates for the two models? With all the external variables normalized out to the extent possible?

The taser-associated death rate shows some evidence of a ramp-up step function starting in 2003.

Up to end-September 2008 [LINK] (*)

(* Note the steep rise in the monthly taser-associated North American death rate, almost a step function, from less than one/month to about seven/month, starting in mid-2003 - strangely coincidental with the introduction of the X26.)


Hello? Anyone out there?

No comments: