A student adds a sound output feature to their design using a small sounder (about the size of your little finger) driven by a logic output from a microcontroller.
The table of frequencies look like this:
100 Hz 200 Hz 300 Hz 400 Hz 500 Hz 600 Hz 700 Hz 800 Hz 900 Hz 1.0 kHz 1.1 kHz 1.2 kHz 1.3 kHz 1.4 kHz 1.5 kHz 1.6 kHz 1.7 kHz 1.8 kHz 1.9 kHz 2.0 kHz 2.1 kHz 2.2 kHzWhy is this wasteful and partly senseless?
Robin
Because nobody has any idea what you're talking about?
etc.
The upper frequencies in the range are going to be too hard to distinguish. For equal distinguishability, you want equal ratios (100, 200, 400...), not equal spacing.
If you want useful sound, the frequencies should be logarithmically spaced like
100Hz, 125Hz, 163Hz, 200Hz, 250Hz, 315Hz, 400Hz, 500Hz, 630Hz, 800Hz, 1k 1k25, 1k63, 2k, 2k5, 3k15, 4k This will give the impression of equal rise throughout the range. It is easy to detect and will give satisfactory results.-- ciao Ban Bordighera, Italy
I overread the size, that thingy wouldn't give any audible output at 100Hz unless you put it right next to the ear. Start with 500Hz or even higher and use closer spaced intervals.
Your prof has the right approach, hope he doesn't flunk you. This world is a bit more than digital and a student should know basic physics and mechanics as well.
-- ciao Ban Bordighera, Italy
If he/she drives it with a square wave it sure will.
John
:) I hope you're wrong about that, but I fear not because something very similar to the above has been in a commercial product for the last ten years.
Cheers Robin
....and this is why no one has noticed the sillyness of it (in the commercial product that it lives in).
It also consumes excessive code. The same audible effects can be produced a lot cheaper. [say five fundamentals? In geometric progression, at the "useable" higher frequencies].
Robin
I fear it will then sound not much different with 300 or 500Hz, the latter being one of the recommended frequencies. The OP talks about a commercial product, what kind of commercial product is it and have you really measured the outputted frequencies? I cannot believe that there are used the stated frequencies.
-- ciao Ban Bordighera, Italy
touch tone dialing? i don't know.
snipped-for-privacy@tesco.net wrote:
That's what I say about MS Windows (as a former Acorn Archimedes user) "I don't believe it, why would anyone buy one of these?" but the Arch' is a commercial failure and the PC is a commercial success.
Robin
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