Crystal oscillators and IC oscillators???

Started by brokenstarguitar, December 18, 2014, 05:44:30 PM

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brokenstarguitar

Can anyone explain the difference between a crystal oscillator and a oscillator IC like a HCF4060BE? And whats the difference between those 2 compared to a programmable oscillator like a CD4541BE? And what exactly does "programmable" mean in reference to programmable oscillator?

R.G.

A crystal oscillator is generally the combination of a crystal and some amplifier/oscillator circuitry in one package. They're available in a huge array of timings.

An oscillator IC like the CD4060 is the amplifier section of a crystal oscillator, plus other junk to do other things; in the case of the 4060, that's a long digital divider as I remember. It needs a crystal or other external timing device(s) to work.

The CD4541 is the combination of an oscillator/amplifier to which a crystal can be connected to oscillate, much like the oscillator section of the CD4060, plus some other junk to do a variable divide/timing setup from the output of the oscillator section. There appears to be a way to select from the clock frequency divided by two to the eighth, tenth, thirteenth, or sixteenth powers, or a digital one-shot based on that timing.

Programmable means you get to select what timing/divide/mode it does by pulling various pins high or low.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

PRR

The "crystal", in this context, is a slab of Quartz which will ring like a bell at a specified frequency when tapped with electricity.

Quartz crystals are the standard way to get a known stable frequency.(*)

You can build a "crystal oscillator" with a crystal and a big old Vacuum Tube. This was the standard radio transmitter for decades. In context of this forum and your questions, that is not the type of crystal oscillator you want.

Today we use various transistors, usually a pre-designed chip, to tap our crystals.

Crystals can only be tuned to "high" frequencies, perhaps 20KHz to 100MHz. Tricks for higher frequency are not needed here. For lower frequencies you use, say, a 100KHz crystal and modern teeny-transistor chips to divide-down the frequency. Divide by 100,000 and you get a once-per-second tick suitable for a clock. Often we prefer /2 /4.../16 ratios because /2 is the basic divider.

Since there are thousands of different applications and ratios, but the chip-maker does not want to make and stock thousands of different parts, they throw in as many dividers as they can and then let you "program" the ratio you want. As R.G. sez, older chips you tie some pins hi/low, which can be jumpers in experimental work or PCB traces in production.

(*) At low frequencies, tuning-forks can be pretty stable, but awkward. I have a tuning-fork watch, there were tuning-fork tuners, but never a real popular thing. L-C and R-C oscillators can give a frequency but must be adjusted and tend to get out of adjustment. Quartz tuning crystals are a mature thing and very stable. "Adjustment" is fussy but done at the factory on automated grinders.
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tubegeek



I've seen this item up close. It uses tuning forks and resonant cavities to perform acoustic additive synthesis. It's pretty cool.
"The first four times, we figured it was an isolated incident." - Angry Pete

"(Chassis is not a magic garbage dump.)" - PRR

Hatredman

Kirk Hammet invented the Burst Box.


tubegeek

"The first four times, we figured it was an isolated incident." - Angry Pete

"(Chassis is not a magic garbage dump.)" - PRR

duck_arse

Quote from: tubegeek on December 23, 2014, 05:59:26 PM
Quote from: amptramp on December 23, 2014, 05:50:41 PM
Quote from: Hatredman on December 23, 2014, 04:22:03 PM
Quote from: tubegeek on December 18, 2014, 09:54:29 PM

Is this a picture of the Burst Box?

It's the version that's not true bypass.

Silly rabbit, there are no pictures of the true bypass burst box.


he's ^^ got a thing about the true bypass version.

You hold the small basket while I strain the gnat.

tubegeek

"The first four times, we figured it was an isolated incident." - Angry Pete

"(Chassis is not a magic garbage dump.)" - PRR