Re: Sample-rate conversion
Re: Sample-rate conversion
- Subject: Re: Sample-rate conversion
- From: Jens Bauer <email@hidden>
- Date: Wed, 4 Feb 2004 14:23:17 +0100
Hi Volker,
On Wednesday, Feb 4, 2004, at 09:11 Europe/Copenhagen, Volker Runkel
wrote:
Hi Jens,
I assume your problem is that you have aliasing effects on account of
the slopes from hi/lo and lo/hi (containing half a dirac delta
function). Square waves produce harmonics (every 2nd = 1st 3rd 5th...)
which get mirrored (by aliasing effects) into your sound range. It
might be helpful to lowpass filter your signal at 22 kHz before
transforming it.
BTW: Where do you get the 3.5 MHz sampled signal from ?
The Sinclair ZX Spectrum had a clock frequency of 3.5 MHz.. It had an
audio-interface like this:
out 254,16 ;set mic low
out 254,0 ;set mic hi
-Since it can do a bunch of changes on the mic port (which is called
mic, because it should be connected to a tape recorder's mic input), it
can reach higher frequencies than a standard sound card. I love this
low-level stuff. =)
Please ask back if the explanation is not easy to understand, but it
is still early in the morning :-)
:) I think I catch most of it. I have been wondering if changing the
square signal to a sine would help getting rid of the extra tone(s).
Volker & Wolfram - just biologists :-)
...You know more about audio than I do... what's your secret - the
buzzing from the bees ? =)
Love,
Jens
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