low ppm crystal clock?m where

[tone]

hi all,
does anybody know where to buy low precision ppm crystal clock?
16.9344mhz & 45.1584mhz.
thanks.

rgds
tone

[Piersma]

http://home.hetnet.nl/~pasopd/crystals.html;)

[Piersma]

Sorry for the bad link............

http://home.hetnet.nl/~pasopd/crystals.html

[casouza]

Hello
There are lots of different manufacturers in that page. Do you have a specific recommendation or can point out which brands/models are low PPM ?
Best wishes

[Elso Kwak]

Originally posted by casouza
Hello
There are lots of different manufacturers in that page. Do you have a specific recommendation or can point out which brands/models are low PPM ?
Best wishes

Hi casouza,
The question for a low ppm crystal I get over and over again.
Let's suppose the crystal is 50ppm too high in frequency. The result will be that the CD-player turns the disc 50 ppm too fast and the music is 50 ppm too high in pitch. Can you hear that??? Musicians are using a tuning fork to stay in pitch. How accurate would that be?. On my table is laying the package of a LCaudioclock. It states 2ppm!
In my opinion what matters is the amount of jitter NOT the accuracy of the crystal. Jitter depends on the circuit used, including the powersupply.

footnote 1ppm = 1 part per million= 1/1000000=1/10000 %

[peranders]

Elso, you are quite right. Exact frequency at varying voltage, temperature, aging etc is overkill if we talk a stand alone CD-player. As you say jitter is the most important parameter and also that the clock signal doesn't interfere with other circuits which can be the case if you tweak too much.

BTW: 2 ppm from, LC Audio, is that really true. What about temperature drift and ageing?

[Elso Kwak]

Originally posted by peranders
Elso, you are quite right. Exact frequency at varying voltage, temperature, aging etc is overkill if we talk a stand alone CD-player. As you say jitter is the most important parameter and also that the clock signal doesn't interfere with other circuits which can be the case if you tweak too much.

BTW: 2 ppm from, LC Audio, is that really true. What about temperature drift and ageing?

Hi Per,
The package has it printed : 2ppm.
The Lcaudio clock has a trimmer cap. If they have a accurate counter and adjust the trimmer I believe the spec.
Yes the clocksignal can interfere with other circuits. I am thinking about shielding the oscillator. The clocksignal can also "travel" through the powersupply to circuits where it is completely unwelcome. A separate clocksupply or a well Pi-filtered supply can improve the situation. I noted in a CD380 when I connected my clock to the +/-15V analog supply sound detoriated considerably even with the PI-filters installed.