# frequency division of sinusoidal waves

Discussion in 'Beginner Electronics' started by A. Walsh, Nov 1, 2003.

1. ### A. WalshGuest

I am wondering if there exists an electronic component which is able
to preform a frequency division of a sine wave (such as a divide by 2
or 4, etc). I am aware of dual flip-flop ICs that are able to freq.
divide square waves, but they are not particularly of interest to
myself unless I absolutely have to use one.
A.W.

2. ### A. WalshGuest

Thank you for taking the time to respond.

I am not sure as to the capabilities of your suggestion,perhaps
you could provide me with some clarification as to the manner in which
the fixed fractioning would be able to be accomplished. The need is
for whatever the component to be able to take an input sine, and
perform said division, as well as to track not only variations of
frequency, such as if the input frequency shifts to any other given
value (which will actually only be within a set range, as yet to be
determined), but also that it be able to track as the amplitude of the
signal decays (I will be able to live without amp. decay tracking,
though it would mean slightly less versatility in use if this isn't
reasonably possible.) An explanation of what I am attempting to do
follows:
I have an interest in creating unique stimuli within the
perception range of humans; currently I wish to design, construct, and
implement the use of, circuitry which will be able to (when activated)
take the 'mixed output' signal from a pair of electric Bass guitar
pickups (the primary sine wave, as well as 3 to 6 of the harmonic sine
waves) use semi-narrow band pass frequency separation, so as to be
able to "treat" each sine individually, then pass each of the
resulting signals through another part of the circuit to divide the
respective frequencies (indeed you are correct in assuming that I wish
to preserve the sine shape, as I am not particularly interested in
mandatory wave clipping as a by-product of what I'm really after),
lowering them by an octave or two, possibly both, followed by the
mixing of the initial freq. as well as any of the treated freq. into a
single output. All of this will take place within the body of the
guitar at the flip of a switch, converting the signal path from an
un-tapped/modified route to one leading through the afore mentioned
circuit, with no other sort of control mechanism. The frequency band
separation I will be able to hardwire and tune to the specifics of
this particular instrument.
There are devices already manufactured that provide similar
functionality, however, they seemingly all have two major
characteristics which I find to be drawbacks: First, and foremost,
current devices make use of converting the input sine waves to square
waves, I don't want to make my instrument sound like a rusty buzz-saw,
thusly the desire to stick with sine wave shape; secondly seemingly
all current such devices also fail to to provide any significant
tracking of the waves (both in parallel across the multi-freq.
spectrum, as well as individually over the decay of amplitude.)
Dividing the signal into semi-narrow bands will hopefully allow for
more versatile tracking across freq.

If you could let me know regarding the fixed fractioning, I will
be ever grateful. Thanks again for stepping up to respond to my post.
-A.W.-

3. ### JimmyGuest

Would be a real trick to do this in real time.

4. ### A. WalshGuest

Thought I'd make a follow up to this quest...
your second post spurred me to research Fourier Transformations; and I
must say, it seems that there might be something that I can do. I'd
likely to quickly clarify: if I was interested in playing straight
rock and roll music, and going for a circuit that was just good enough
to accomplish what I'm after, I would probably take the route of
people who have come before me . After reading about a company who
designed a hearing aide to do pretty much exactly what I need (for
people who do not have the greatest of capacity to hear the higher
registers, the device reproduces the sound information at lower freq.
rates; not for guitars), I spent the day pondering over a number of
things.
If I really wanted to have absolute precision in the freq.
shifting, it's possible that I could rig something up using an old 486
cpu at the core to analyze all of the functions needed, matching even
the most slight of harmonics. This does not, in particular, appeal to
me; I don't want to have to figure out the logistics of retro-fitting
a computer into a 3.5x4.5x2 inch hole within the bass guitar, plus,
this would mean that I would be pretty much locked into the digital
domain... and we all know what can happen when digital circuits fail
to function in the ways which we expect. Though, with an analogue
circuit there are potentially more things able to go wrong due to the
environmental circumstance. None-the-less, if ever I am out some
place playing and suddenly the bass begins to malfunction (aside from
being easier to explain to people why the sounds of an analog
disruption happen, as opposed to say... the sound of a dieing modem
from a bass guitar...) there may not be such a ready way to 'solve'
the problem so to speak if a digital failure happens, such as the
commonality of certain tools, where as one might be able to jerry-rig
a fix out of things found in most small town hardware stores.
So, what to do aside from out-right main-boarding the bass? The
hearing aide people describe a modified DFT, which from the results of
their testing seems to be able to track with the variations in a human
voice (primary freq., residual harmonics, overtones, etc). So cool.
Amplitude/voltage regulation aside, essentially pop open the back of
the Bass, wire the hearing aide in series between the pickups and the
output-jack, configured, of course, with a bypass switch, and good to
go. But then I got to thinking: even if it were really that simple
(which isn't likely), it still locks me into the digital domain.
After having experienced the thrills of a multitude of musical
instrumentation, learning to play piano, baritone tuba, guitar,
pan-flute, violin, dulcimer, diggerido, the bass (upright, and
electric), cello, as well as a variety of other stringed instruments
plus having years of choral experience, though all of the above only
to a moderate level... by no means am I attempting to imply anything
about my ability to manipulate anything musical with any lack-luster
skill; and then recently learning about the history of the advent of
the piano... and all the trouble faced in designating a standard
tunning (which by the way, I'm told, is that all keys that one might
wish to play the piano in are equally out of tune from the natural
harmonics.) I've decided that I wish to fore-go the whole advent of
digital music, and spent the afternoon de-fretting the electric bass
guitar that this whole modification will be used in conjunction with
(I'm also a budding audiophile). As an added benefit of using
analogue, interesting results have been known to suddenly show up with
partial, and at times acceptable, 'failures' of electronic
representations of functions.
Having said that, and still wishing to come up with some sort of
solution... and also remembering one of the basic principles of
electronics: if it is possible to build a circuit of the digital
nature, then it is also possible to construct a similar circuit of the
analogue nature (though precision, over-all life continuity, and at
times rate of speed for circuit completion, may be sacrificed)... I
have now begun to look into continuous Fourier transform circuits.
It may also come as a surprise for you that I'm just a 20 year
old college student, and that I'm interested in more than the crude
aspects of making noise. But what can I say, I like to have fun, and
that's why I am very glad that you have taken up aide-ing me with this
particular quest, thank you much.

Oh yeah, perhaps you might be able to answer an almost totally
unrelated question:
Does such a device exist, which acts principley as a pot. though wired
so as at the maximum setting in one direction the resistance in
negligible, followed by an "off", or relatively high resistance at
about the median of the range, with the max. setting on the other end
also being with negligible resistance (though from another circuit
path)? Essentially what I'm after is this: A volume knob which takes
the direct feed from a set of guitar pickups, and functions over half
of the overall range as a standard volume control, but ending (being
"off") at the mid-point, and then switching to a mirrored volume
function on the other half, but in place of straight signal, taking
input from the circuit that I'm working on to do all the freq.
modification. (kind of like a volume knob/effect pedal on/off switch
rolled into one) If such a thing does not already exist (meaning
purely mechanical, I'm fairly sure that there are ICs which can do
something along these lines), does it seem reasonable to think that
someone could, given the tools required to assemble it into a pot.
style, actually build one? I really will only be running the whole
machine at "full on" volume, but I don't want to blow any speakers
along the way switching from straight feed to processed (I use
outboard volume controls, such as on an amp, or preamp if recording,
to adjust the play volume, or, if there is a need for sudden change, I
modify the dynamics of my playing style, and don't use volume controls
anyways)
Anyways, thanks again.
-A.W.-

5. ### A. WalshGuest

Though I must say... going the TI chip route does sound oftly
tempting...
tell you what Don, if I take a shot that way, perhaps making similar
things for other people, and come up with a sizable amount of spare
change, I'll send a chunk your way. Of course, seeing as I'd keep the
whole circuit filed under public domain, that spare change jar may not
grow with any significant rate. None the less, I'll take a look into
it {grin}
-A.W.-

6. ### A. WalshGuest

What sort of circuit would be able to do this with changing the
amplitude, as I might be able to rig a sort of pre-amp device pre or
post... sure not the best solution, but until I take some hard core
time to research building conceptual electronics, it could allow proof
of concept, as well as a chance to play around and see if such a
process is desireable.