Knock

[Tony Cooper]

bruce plecan wrote:
> 
> ref Tony Cooper:
> OK, after thinking about your statement, it does make
> sense about the detonation/knock at peak toque,
>   Then you go on to say the it is the same frq. that
> it listens for all the time.  Is that to say this
> collison of the flame fronts generate the same
> sound reguardless of timing/rpm??
>   The above is again engine specific.
> TIA  Bruce

Sorry I may have slightly missled. What I think I said was it would have
the same FFT footprint. A FFT foot print is the spike in the frequecny
specrtum plus all its harmonics - AFTER doing the FOURIER ANALYSIS of
the signal from the microphone.

This 'footprint' can move up and down the frequency range a little bit,
but it will still look the same as the basic footprint. This footprint
is based on the natural resonance of the engine when it is detonating -
and therefore will be the same (Virtually) for all RPM's

Hoe this helps
Tony
(I am sure I will get flamed if I am wrong)
-- 
Sent By Tony Cooper.
email: tony.cooper at virgin.net
Allow at least 10 working minutes for reply. ;)