Hi folks,
I have acquired of the MESA Quartz Crystals to approximately 160 Mhz
fundamental AT.
Someone knows some circuit for their use?
73's de IK6GQC Rocco

Here is a low phase noise oscillator circuit for a Analog Devices AD9850
DDS:

http://www.analog.com/UploadedFiles/...13367an419.pdf

73,

Mike N2MS



"Mario Bros" wrote in message
...
Hi folks,
I have acquired of the MESA Quartz Crystals to approximately 160 Mhz
fundamental AT.
Someone knows some circuit for their use?
73's de IK6GQC Rocco

Hi Mike, thank you.
I am not sure that the circuit is good also for the type of crystal that I
have.
That one used in this plan is a 7th while the mesa it is a fundamental AT.

73's de IK6GQC Rocco

"Michael St. Angelo" ha scritto nel messaggio
...
Here is a low phase noise oscillator circuit for a Analog Devices AD9850
DDS:

http://www.analog.com/UploadedFiles/...13367an419.pdf

73,

Mike N2MS



"Mario Bros" wrote in message
...
Hi folks,
I have acquired of the MESA Quartz Crystals to approximately 160 Mhz
fundamental AT.
Someone knows some circuit for their use?
73's de IK6GQC Rocco

A crystal running in 7th overtone mode has a narrow little resonance
surrounded by other resonances (the 9th and 5th) which must be filtered out.

A crystal running in fundamental mode has a pronounced resonance, with
no other significant resonances until you get to three times the
operating frequency.

If there's anything "wrong" with that circuit it's most likely that the
frequency selective elements to keep it from jumping to 89 or 161MHz.
It may also deliver more feedback to the crystal than absolutely
necessary (dunno about that). So if anything is bad about it it's just
that it has too many components.

It's probably a very good place to start, and should work as-is if you
get the tank tuned right.

Mario Bros wrote:

Hi Mike, thank you.
I am not sure that the circuit is good also for the type of crystal that I
have.
That one used in this plan is a 7th while the mesa it is a fundamental AT.

73's de IK6GQC Rocco

"Michael St. Angelo" ha scritto nel messaggio
...

Here is a low phase noise oscillator circuit for a Analog Devices AD9850
DDS:

http://www.analog.com/UploadedFiles/...13367an419.pdf

73,

Mike N2MS



"Mario Bros" wrote in message
. it...

Hi folks,
I have acquired of the MESA Quartz Crystals to approximately 160 Mhz
fundamental AT.
Someone knows some circuit for their use?
73's de IK6GQC Rocco








--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Ok! Tim. I will try.
What it interests to me is to try to use it x3 (480 Mhz) for reference DDS
AD9954.
Thanks




"Tim Wescott" ha scritto nel messaggio
...
A crystal running in 7th overtone mode has a narrow little resonance
surrounded by other resonances (the 9th and 5th) which must be filtered
out.

A crystal running in fundamental mode has a pronounced resonance, with no
other significant resonances until you get to three times the operating
frequency.

If there's anything "wrong" with that circuit it's most likely that the
frequency selective elements to keep it from jumping to 89 or 161MHz. It
may also deliver more feedback to the crystal than absolutely necessary
(dunno about that). So if anything is bad about it it's just that it has
too many components.

It's probably a very good place to start, and should work as-is if you get
the tank tuned right.

Mario Bros wrote:

Hi Mike, thank you.
I am not sure that the circuit is good also for the type of crystal that
I have.
That one used in this plan is a 7th while the mesa it is a fundamental
AT.

73's de IK6GQC Rocco

"Michael St. Angelo" ha scritto nel messaggio
...

Here is a low phase noise oscillator circuit for a Analog Devices AD9850
DDS:

http://www.analog.com/UploadedFiles/...13367an419.pdf

73,

Mike N2MS



"Mario Bros" wrote in message
.it...

Hi folks,
I have acquired of the MESA Quartz Crystals to approximately 160 Mhz
fundamental AT.
Someone knows some circuit for their use?
73's de IK6GQC Rocco








--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you know what load they are cut for? That osc is for overtone operation
and those usually run the crystal in series mode.

Start using Google more... This may be just what you need.

http://www.sss-mag.com/pdf/saosc.pdf
I'm not familiar with MESA's, but If this is the crystal type, this may
help.
It is just for MESA resonators and appears to say they are series cut. It
also looks like a good general reference on crystal characteristics as it
shows the typical resonances at the overtones.

http://www.icmfg.com/crystaloscillatordata.html
If I thought they were parallel load xtals, I'd start with the fundamental
Colpitts if they are parallel crystals, but a tuned circuit may help to
improve the phase noise.

73, Steve K,9.D;C'I



"Mario Bros" wrote in message
...
Hi folks,
I have acquired of the MESA Quartz Crystals to approximately 160 Mhz
fundamental AT.
Someone knows some circuit for their use?
73's de IK6GQC Rocco

Hi Steve,
you see this link
http://daten.ws-mack.de/Freigabe/kvg.../Kat2/8_F4.pdf

My crystal is 155.520 Mhz.

I will make some test as you have suggested to me.

Merry Christmas for all.

IK6GQC Rocco


"Steve Nosko" ha scritto nel messaggio
...
Do you know what load they are cut for? That osc is for overtone
operation
and those usually run the crystal in series mode.

Start using Google more... This may be just what you need.

http://www.sss-mag.com/pdf/saosc.pdf
I'm not familiar with MESA's, but If this is the crystal type, this may
help.
It is just for MESA resonators and appears to say they are series cut. It
also looks like a good general reference on crystal characteristics as it
shows the typical resonances at the overtones.

http://www.icmfg.com/crystaloscillatordata.html
If I thought they were parallel load xtals, I'd start with the fundamental
Colpitts if they are parallel crystals, but a tuned circuit may help to
improve the phase noise.

73, Steve K,9.D;C'I



"Mario Bros" wrote in message
...
Hi folks,
I have acquired of the MESA Quartz Crystals to approximately 160 Mhz
fundamental AT.
Someone knows some circuit for their use?
73's de IK6GQC Rocco

OK Rocco,
Now that I read the paper (URL below) on MESA crystals, I can comment
better. They are nothing more than very thin AT crystals (in the center of
a larger, thicker blank) and therefore have the normal AT cut
characteristics.
The reference you give below is a general datasheet from the manufacturer.
However, when crystals are manufactured they are made to a specific
requirement with regard to what is called "load". This would have been at
the request of the Engineer ordering the crystals. As explained in the
paper I referenced, crystals can be used either in a parallel resonance mode
or a series resonance mode.

Any crystal can be operated in either mode (any crystal can also be operated
in one of its overtone modes - I have done this), but to get the frequency
that it was manufactured for (and marked) you have to operate it in the mode
it was made for. Therefore, if you expect to get the frequency on the
crystal, you have to operate it in the correct mode. Just looking at the
crystal, you can not tell for which mode or load capacitance it was made.

If you put a crystal in an oscillator which runs the crystal in series mode
and the frequency is too low, then it was made for parallel operation and
needs a parallel type circuit like the Collpits. If a crystal is put into a
parallel mode circuit and it can't be brought down to the marked frequency,
then it is a series mode crystal. If I recall, the Pierce operates the
crystal in series mode. For reference, if I recall the difference between
the parallel mode frequency and series mode frequency is around 200-300 ppm.
for fundamental crystals in the 1-30 MHz range.

For lower frequency crystals it is common to specify in the range of 20-32
Pf load for parallel mode operation. There is no analogous "value" for a
series operated crystal...just saying "series" is enough.

Another consideration not mentioned in the overview paper that I reference
is that of power dissipation. Putting too much energy into the crystal will
heat the material and cause frequency drift. Though not discussed, I can
only speculate that the MESA construction requires a lower power operation
than non MESA because of the thin blank.
73, Steve, K,9.D;C'I


"Mario Bros" wrote in message
...
Hi Steve,
you see this link

http://daten.ws-mack.de/Freigabe/kvg.../Kat2/8_F4.pdf

My crystal is 155.520 Mhz.

I will make some test as you have suggested to me.

Merry Christmas for all.

IK6GQC Rocco


"Steve Nosko" ha scritto nel
messaggio
...
Do you know what load they are cut for? That osc is for overtone
operation
and those usually run the crystal in series mode.

Start using Google more... This may be just what you need.

http://www.sss-mag.com/pdf/saosc.pdf
I'm not familiar with MESA's, but If this is the crystal type, this may
help.
It is just for MESA resonators and appears to say they are series cut.
It
also looks like a good general reference on crystal characteristics as
it
shows the typical resonances at the overtones.

http://www.icmfg.com/crystaloscillatordata.html
If I thought they were parallel load xtals, I'd start with the
fundamental
Colpitts if they are parallel crystals, but a tuned circuit may help to
improve the phase noise.

73, Steve K,9.D;C'I



"Mario Bros" wrote in message
...
Hi folks,
I have acquired of the MESA Quartz Crystals to approximately 160 Mhz
fundamental AT.
Someone knows some circuit for their use?
73's de IK6GQC Rocco

"Steve Nosko" writes:

Do you know what load they are cut for? That osc is for overtone operation
and those usually run the crystal in series mode.

If he doesn't care about absolute accuracy, series or parallel mode is not
a concern. The LC tank will reduce phase noise, but shouldn't have a Q of
more than about 10-20. If you tune the tank for max amplitude, you are sure
to be at the right operating point for the xtal.

Steve
(part of AN419)

--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA