"PDRUNEN" wrote in message
...
Hi Group,

I have a crystal marked 100MHz, it the smaller package found in the CBs.

What I want to do is connect this up to a ECL or Fast TTL and get a 0 to 5
Volt
square wave output that can drive 50 ohms with 2.5 volts or more.

Anyone have a good circuit or suggestions?

Tnx de KJ4uo

It will oscillate at the fundamental, not the marked 100 MHz overtone
frequency. At 100 MHz, I'd guess that's a 7th or 5th overtone cut.
Most likely 7th, 20 MHz is about the limit for fundamental crystals.

Pete

" Uncle Peter" wrote in message
news0bZc.124585$Lj.108231@fed1read03...

"PDRUNEN" wrote in message
...
Hi Group,

I have a crystal marked 100MHz, it the smaller package found in the CBs.

What I want to do is connect this up to a ECL or Fast TTL and get a 0 to
5
Volt
square wave output that can drive 50 ohms with 2.5 volts or more.

Anyone have a good circuit or suggestions?

Tnx de KJ4uo

It will oscillate at the fundamental, not the marked 100 MHz overtone
frequency. At 100 MHz, I'd guess that's a 7th or 5th overtone cut.
Most likely 7th, 20 MHz is about the limit for fundamental crystals.

That used to be the case, but 40 MHz fundamental crystals have been
available for some time. I've got some.

Leon

"Leon Heller" a écrit dans le message de
...
" Uncle Peter" wrote in message
news0bZc.124585$Lj.108231@fed1read03...

It will oscillate at the fundamental, not the marked 100 MHz overtone
frequency. At 100 MHz, I'd guess that's a 7th or 5th overtone cut.
Most likely 7th, 20 MHz is about the limit for fundamental crystals.

That used to be the case, but 40 MHz fundamental crystals have been
available for some time. I've got some.


I guess this is not for the garden variety crystals, but I've seen (can't
remember where) that IC etching technology has been applied to crystals
manufacturing which resulted in crystals of over 200MHz fundamental
frequency.


--
Thanks,
Fred.

On Tue, 31 Aug 2004 23:05:53 -0400, " Uncle Peter"
wrote:

It will oscillate at the fundamental, not the marked 100 MHz overtone
frequency. At 100 MHz, I'd guess that's a 7th or 5th overtone cut.
Most likely 7th, 20 MHz is about the limit for fundamental crystals.

So how does one tell if the xtal is fundamental or overtone? Not for
xtals marked 100Mhz, obviously, but for much lower frequencies which
could be either..
--

"What is now proved was once only imagin'd." - William Blake, 1793.

Paul Burridge wrote in message . ..
On Tue, 31 Aug 2004 23:05:53 -0400, " Uncle Peter"
wrote:

It will oscillate at the fundamental, not the marked 100 MHz overtone
frequency. At 100 MHz, I'd guess that's a 7th or 5th overtone cut.
Most likely 7th, 20 MHz is about the limit for fundamental crystals.

So how does one tell if the xtal is fundamental or overtone? Not for
xtals marked 100Mhz, obviously, but for much lower frequencies which
could be either..

Easy. Look for resonances near 33.3MHz, 20MHz and 14.3MHz. Or...put
it in an oscillator circuit which favors fundamental mode and see
where it oscillates.

Cheers,
Tom

"Paul Burridge" wrote in message
...
On Tue, 31 Aug 2004 23:05:53 -0400, " Uncle Peter"
wrote:

It will oscillate at the fundamental, not the marked 100 MHz overtone
frequency. At 100 MHz, I'd guess that's a 7th or 5th overtone cut.
Most likely 7th, 20 MHz is about the limit for fundamental crystals.

So how does one tell if the xtal is fundamental or overtone? Not for
xtals marked 100Mhz, obviously, but for much lower frequencies which
could be either..

I have used fundamental cut crystals on their overtones and overtone
crystals on their fundamental. NOTE, the frequencies will NOT be exact
harmonics/multiples. Somewhere I have information giving the typical
differences.


The crystal Colpitts is one sure bet. Stay away from circuits with
inductors and tuned circuits for a fundamental oscillator. Some IC
oscillators can give misleading results. They can pound the rock too hard.


here's some circuits thanks to GOOGLE:

This type is my favorite. Used in just about all Motorola channel elements
of Motrac through Micor and probably beyond.
http://homepage.tinet.ie/~ei9gq/tx_circ.html
Though seems to me, the lower cap should be 100 rather than 220pf, but they
are REALLY non critical. One page I found had them both at 1000pf.

Fig 7 looks the same:
http://www.northcountryradio.com/PDFs/column007.pdf



Discover Circuits also has a lot of circuits.
http://www.discovercircuits.com/O/o-crystal.htm


--
Steve N, K,9;d, c. i My email has no u's.

P.S. the Educypedia has lots of circuit ideas, in general
http://users.telenet.be/educypedia/e...osciltypes.htm



If you do your own search, THIS is NOT a Colpitts crystal osc...
http://www.designnotes.com/CIRCUITS/colpitts.htm

(PDRUNEN) wrote in message ...
Hi Group,

I have a crystal marked 100MHz, it the smaller package found in the CBs.

What I want to do is connect this up to a ECL or Fast TTL and get a 0 to 5 Volt
square wave output that can drive 50 ohms with 2.5 volts or more.

Anyone have a good circuit or suggestions?

Suggestion: just get a 100MHz TTL oscillator. I believe Harold
offered you one last time you posted about 100MHz xtals a couple years
ago. ECL won't have 2.5V output, but I could supply you with a nice
little PECL 100MHz VCXO that you could easily trim to "exactly"
100MHz. It will deliver about 800mV p-p into 50 ohms.

Cheers,
Tom

On 1 Sep 2004 09:59:49 -0700 (Tom Bruhns) wrote:

Suggestion: just get a 100MHz TTL oscillator. I believe Harold
offered you one last time you posted about 100MHz xtals a couple years
ago. ECL won't have 2.5V output, but I could supply you with a nice
little PECL 100MHz VCXO that you could easily trim to "exactly"
100MHz. It will deliver about 800mV p-p into 50 ohms.

What is PECL?

What kind of stability and aging could I expect from this oscillator?

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

"Jim Adney" wrote in message
...
On 1 Sep 2004 09:59:49 -0700 (Tom Bruhns) wrote:

Suggestion: just get a 100MHz TTL oscillator. I believe Harold
offered you one last time you posted about 100MHz xtals a couple years
ago. ECL won't have 2.5V output, but I could supply you with a nice
little PECL 100MHz VCXO that you could easily trim to "exactly"
100MHz. It will deliver about 800mV p-p into 50 ohms.

What is PECL?

Plessey emitter-coupled logic, like MECL, which is made by Motorola.

Leon

From: "Leon Heller"
Newsgroups: rec.radio.amateur.homebrew
References:


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"Jim Adney" wrote in message
.. .
On 1 Sep 2004 09:59:49 -0700 (Tom Bruhns) wrote:

Suggestion: just get a 100MHz TTL oscillator. I believe Harold
offered you one last time you posted about 100MHz xtals a couple years
ago. ECL won't have 2.5V output, but I could supply you with a nice
little PECL 100MHz VCXO that you could easily trim to "exactly"
100MHz. It will deliver about 800mV p-p into 50 ohms.

What is PECL?

Plessey emitter-coupled logic, like MECL, which is made by Motorola.

Leon




PECL is ECL run from a positive supply. ECL is normally run from a negative
supply respect to ground. So, they have the sme swings, but different "bias"
levels.

Jure Z.