Re: Test report MBP built-in audio device
Re: Test report MBP built-in audio device
- Subject: Re: Test report MBP built-in audio device
- From: Richard Dobson <email@hidden>
- Date: Thu, 28 Aug 2008 15:56:47 +0100
Mikael Hakman wrote:
Brian,
..
The very first chart in my report at
http://www.dkab.net/Realtek HDA report.pdf shows you Impulse
Response for the actual device. It is entitled Single Pulse Response
because this name is easier to understand for people I presume will read
that report. The name Impulse Response is used in signal processing. In
even more mathematically oriented papers it is often called Transfer
Function.
It is correct that for an ideal linear time-invariant system, its
Transfer Function tells you all, in mathematical sense that is. This
means that given any kind of input and system's transfer function, you
can compute system's response (output). This is done by convolution of
input and transfer function.
..
I do not disclose all the details because I don't want to. You'll see
some of the details in the forthcoming proper paper if you read that
kind of press that is. You won't see all the details until there is
valid patent in place.
Perhaps you can at least say what the patent is for - some device that
eliminates (linearizes?) the, um, distortion, caused by DC and
anti-alias filters attached to a codec when fed a signal with short-term
aliasing (i.e. with an onset discontinuity)? Or a codec chip that
doesn't need them? Either would be remarkable, and should generate a
considerable income stream. If only one could do the same for loudspeakers.
Where will you be submitting your paper? I have access to the AES
Journal, and also any IEEE publication (via an academic gateway).
Anything else I should look out for?
In the meantime, perhaps you would consider copying your original post
to comp.dsp, where you will be able to discuss impulse responses, LTI
(or not) systems, transfer functions and convolution without compromise.
Many industrially-employed dsp professionals are on that list (to say
nothing of those who have also authored primary books on dsp), so they
fully understand the need for less than full disclosure. They are the
sorts of folk who would likely be the peers who would review your paper.
I think they may nevertheless be surprised to hear that the Impulse
Response is also known as the Transfer Function, and may need some
mathematical clarification.
Richard Dobson
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