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Old 3rd November 2013, 12:22 AM   #271
Wungun is offline Wungun  Canada
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Is that a lot of jitter...? Seems high...


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Old 3rd November 2013, 01:55 AM   #272
amc184 is offline amc184  New Zealand
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Thanks for the measurements Andrea, they're really interesting to see, and I have no hope of making them myself. I'm pretty happy, -108dBc/Hz @ 10Hz is a solid number, though the noise floor of -147dBc/Hz could be better. What do you think the three spurs are, reflections?
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Old 3rd November 2013, 11:40 AM   #273
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Quote:
Originally Posted by amc184 View Post
Thanks for the measurements Andrea, they're really interesting to see, and I have no hope of making them myself. I'm pretty happy, -108dBc/Hz @ 10Hz is a solid number, though the noise floor of -147dBc/Hz could be better. What do you think the three spurs are, reflections?
The measurement has been done in a university lab. It did take 5 minutes only to do the measurement, I believe in an hour or so the phase noise performance should be better, also the noise floor.
BTW, it's not a bad phase noise plot, it's at least 6dB better than the Crystek or Tentlabs XO.
About the spurs, I don't know. I measured the DC version powered by a LiFePo battery followed by an LC filter.

About the jitter, it depends on how many segments have been integrated. The measurement have been done very close to the carrier (1Hz), so the first segment is dominant. Tipically the manufacturers start the measurement at 10Hz from the carrier, so the RMS phase jitter seems much better.
Attached a simple phase noise to jitter conversion of this oscillator starting from 1 and 10Hz. As you can see the results are a bit different: around 20 ps starting from 1Hz, but less than 0.3 ps starting from 10Hz.

Andrea
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File Type: jpg Clark_Jitter_01.jpg (74.1 KB, 313 views)
File Type: jpg Clark_Jitter_10.jpg (72.1 KB, 306 views)
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Old 4th November 2013, 03:24 AM   #274
amc184 is offline amc184  New Zealand
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@andrea_mori: Yeah, that makes sense. The 20ps number threw me off at first, 0.2ps seems a much more compatible number to other oscillators, I think 10Hz is the normal starting point. That's why I always prefer to look at a phase noise plot, jitter numbers can be easily distorted.

There's been a bit of interest in kits again. I will be ordering parts, so kits will be available again. PCBs are always available. DC kits are USD30, AC kits are USD40, bare PCBs are USD3 (kits include a bare PCB), same as the second round of the groupbuy.
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Last edited by amc184; 4th November 2013 at 03:30 AM.
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Old 4th November 2013, 06:14 AM   #275
amc184 is offline amc184  New Zealand
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I've prepared an order for parts for the kits, it's been a while since the last group buy round so there have been a few changes to the bill of materials. Notably:

- Some kits will get LM431s instead of TL431s, they're both the same thing.
- Block VB1.5/2/6 transformers instead of the Myrra 44091. They're equivalent, I'd have rather used the Myrra as they're cheaper, but my normal supplier is out of stock. A reminder that these are 220 to 240VAC transformers, if you're from a 100 to 120VAC country, please stick to the DC kits.

The other thing is crystals. Last time I shipped three crystals (11.2896, 16.9344 and 33.8688MHz) with each kit, I think this time I'll ship up to two of your choice from the following list:

- 11.2896MHz Citizen HC49US
- 12.288MHz Citizen HC49US
- 16.9344MHz TXC HC49S
- 24.576MHz TXC HC49S
- 33.8688MHz Generic

I'll only have so many of each though, I may run out of a particular value.

Attached is an up to date schematic and bill of materials.
Attached Files
File Type: pdf LJC B4 2013.pdf (66.9 KB, 69 views)
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Old 4th November 2013, 02:12 PM   #276
Wungun is offline Wungun  Canada
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Yes!!!



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Old 7th November 2013, 12:57 AM   #277
qingcai is offline qingcai  United States
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do you have 25Mhz version.

thanks

Quote:
Originally Posted by amc184 View Post
I've prepared an order for parts for the kits, it's been a while since the last group buy round so there have been a few changes to the bill of materials. Notably:

- Some kits will get LM431s instead of TL431s, they're both the same thing.
- Block VB1.5/2/6 transformers instead of the Myrra 44091. They're equivalent, I'd have rather used the Myrra as they're cheaper, but my normal supplier is out of stock. A reminder that these are 220 to 240VAC transformers, if you're from a 100 to 120VAC country, please stick to the DC kits.

The other thing is crystals. Last time I shipped three crystals (11.2896, 16.9344 and 33.8688MHz) with each kit, I think this time I'll ship up to two of your choice from the following list:

- 11.2896MHz Citizen HC49US
- 12.288MHz Citizen HC49US
- 16.9344MHz TXC HC49S
- 24.576MHz TXC HC49S
- 33.8688MHz Generic

I'll only have so many of each though, I may run out of a particular value.

Attached is an up to date schematic and bill of materials.
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Old 8th November 2013, 11:45 AM   #278
Wungun is offline Wungun  Canada
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@amc184....

Please put me down for 1 DC kit please...
Email me:
w-u-n-g-u-n@hotmail.com

Regards,
Eric


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Old 10th November 2013, 07:40 AM   #279
amc184 is offline amc184  New Zealand
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I've now ordered parts for a few kits, everything should arrive within a week or so. I've only bought DC kit parts, as I couldn't get the transformer I wanted at the moment, and everyone so far has ask for DC kits anyway.
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Old 11th November 2013, 11:37 AM   #280
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Hi, I would like to have 1 DC kit, freq = 16.9344MHz.
What is the output Vp-p?
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