Asynchronous I2S FIFO project, an ultimate weapon to fight the jitter

If i use a lifepo battery to power the clock board, and a part of the isolation board. I could attach the power from the battery management unit to the USB power of the raspberry pi, and regulated 3.3V from this board: https://www.sparkfun.com/products/8376

Would it work if it is in an always on set-up?

To quote myself; I've found something that could work trying to use this charger with the Batery Management board. Without using the relays.

https://www.tindie.com/products/xorbit/lifepo4weredusb/

Probably replace the battery to the A123s.

What do you guys think?
 
I wonder how they measure the phase noise of DuCULoN. By Agilent signal analyzer? If this DuCULoN has unprecedented performance, what's the clock inside the signal analyzer? It should be less noise than DuCULoN, right?

I think phase noise characteristics are measured by using Agilent Signal Source Analyzer E5052B. I have no idea on oscillators employed for sampling in the analyzer.
 
I think phase noise characteristics are measured by using Agilent Signal Source Analyzer E5052B. I have no idea on oscillators employed for sampling in the analyzer.

I found the picture and the base band noise figure of this particular OCXO used in Agilent E5052B. Actually, someone is selling used parts on ebay. I borrowed the picture.
It looks like it has better close-in performance than DuCULoN, but DuCULoN is better at higher frequency and so is the noise floor. Interesting.


e5052b_ocxo.jpg




e5052b_1.png
 
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I found the picture and the base band noise figure of this particular OCXO used in Agilent E5052B. Actually, someone is selling used parts on ebay. I borrowed the picture.
It looks like it has better close-in performance than DuCULoN, but DuCULoN is better at higher frequency and so is the noise floor. Interesting.

It's very interesting document and picture!
As all of you may know, "close-in" phase noise measurement values depend on its main carrier frequency. The values increase roughly 10 dB as the frequency doubles. The OCXO unit in the picture seems to be 10 MHz one while DuCULoN is 45 or 49 MHz one.
DuCULoN employs a filtering crystal in order to reduce phase noises at a floor region. That's why the unit shows better values at the range.
 
bkdog: the 957's is not avaliable at 9x.xxMHz frequencies, while the 950's are. Earlier i have only seen the 950's in 80/100MHz though, while these two are for sync 44/48 frequencies.

Over at HifiDuino (http://hifiduino.wordpress.com/2012/08/27/crystek-cchd-957/) it is suggested that the CCHD-957 has significantly less jitter than the CCHD-950.

The Crystal specs suggest the same: http://www.crystek.com/crystal/spec-sheets/clock/CCHD-950.pdf http://www.crystek.com/crystal/spec-sheets/clock/CCHD-957.pdf

Unless there is something special about these Ian?

Thanks RollE2k,

That's what I meant:)

Regards,
Ian
 
For such low Frequency DAC as the TDA1541A if you have this chip, is there according to you a good trade off betwenn the half/full speed modes of the boards and the minimum Fhz value of the crystals ?

Better e.g. to stay at 22/24 KhZ XO for playing max 96 K Hz materials and that's it ?


Please : Did anyone try to feed the Crystal and PCM board from the same A123 cell and same battery management board ? Possible at the cost of less battery life without loss of quality, gnd loops, etc ?
 
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A good way to try 380 K oversampling with tda-1541A.... cool ! Look forward to read your review at these speeds and 950 Crystek !:)

Ian please, do you use the PCM board at half or full speed with your 45/49 XOs and TDA1541A dac ?

Hi Eldam,

I tested TDA1541A with PCM board up to 98.3040MHz MCLK a year ago. It was running perfectly without any problem. 45/49 should be the same. So please go ahead and let us know your update.

Regards,
Ian
 
Thanks Ian,

I have some problem yet with the PCM board, I should continue to test it,

Does the FGPA on it could support 5V clock injection :eek: ! I have to check with my other pcm board didn't test it yet ! The CDHH-957 45/49 work fine at full speed in normal I2S mode for the moment with clock board II at full speed (default setup) mode ! So my understanding from your answer is the PCM need full speed as well to play with 98 K XO !

Is it possible according to you to feed the PCM and the clock board II from the Battery management kit with a standalone A123 cell (by doubling the output wire and removing the embeded ldo of the pcm board to allow it to play at 3.2 V directly ?

No problem of ground loop like this, if the clock board and PCM board are sharing the same battery ?

Also : I heard most people can hear any difference when upsampling from 192 K Hz to 380 K with such old DAC chip, what is your experience with this please ?
 
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