Tcxo

[XTAL]

Dear All,
I want to build a DAC.
The combination CS8414 --> DF1704 -->PCM1704.
Q1 : I read the page 6 of DF1704 spec. sheet. The table show the fs 44.1k (It means the CD player O/P? It's fixed value ?). So I can only apply the 11.2896, 16.9344 and 22.5792 ?
Q2 : Do you have any web site will sell the TCXO like the above frequency? Please recommand.

Thanks a lot

[Guido Tent]

Hi

Why do you look for a temperature controlled XO ?

Guido

[XTAL]

I think it will be more precision.

[Guido Tent]

Originally posted by XTAL
I think it will be more precision.

Hi

It is more stable as function of temperature, but that is of no imprortance for audio, as long as the redbook specs are respected (+/- 100ppm)

cheers

[Fin]

Hi Guido

Which type of XO gives the best results - VCXO or XO (like the XO2 module)?

[BlairHatcher]

Hello Fin,
although I am not Guido I can probably answer your question.
A voltage controlled osc is not really required for the application you are going to use it for.
The added complexity of the osc circuit will make the Phase Noise ( Jitter ) performance of the osc worse and good Phase Noise performance is what you are really after.

Regards
Blair

[banana]

hi XTAL,

TCXO (Temperature Compensated Crystal Oscillator) belongs to the higher grade oscillator and usually have better temperature stability as well as frequency stability, and hopefully less jitter.

You may have a look around Farnell and Digikey for TCXO.

BTW, do you really need a crystal in your config?

Figure14 on DF1704 datasheet (page16) shown how DF1704 XTI is connected from the CS8414 MCK (pin19). I guess if you feed 16.934MHz crystal into XTI (running 384fs), your DAC will only accept 44.1KHz sampling rate but not 48KHz or 96KHz.

[BlairHatcher]

Hi Xtal,
purchasing a TCXO rather than a XO does not guarantee you that the jitter performance will be any better than a XO.

A well made XO will have better jitter performance compared to a TCXO using the same circuit topology . This is due to the compensation network normally ( resistor / capacitor and themister ) adding additional noise.

Regards
Blair

[Guido Tent]

Originally posted by BlairHatcher
Hello Fin,
although I am not Guido I can probably answer your question.
A voltage controlled osc is not really required for the application you are going to use it for.
The added complexity of the osc circuit will make the Phase Noise ( Jitter ) performance of the osc worse and good Phase Noise performance is what you are really after.

Regards
Blair

Hi

Nothing to add, perfect answer (though realy good VCXO's are nearly as good as free running oscs, but not as good.......)

cheers

[Guido Tent]

Originally posted by banana
hi XTAL,

TCXO (Temperature Compensated Crystal Oscillator) belongs to the higher grade oscillator and usually have better temperature stability as well as frequency stability, and hopefully less jitter.

You may have a look around Farnell and Digikey for TCXO.

BTW, do you really need a crystal in your config?

Figure14 on DF1704 datasheet (page16) shown how DF1704 XTI is connected from the CS8414 MCK (pin19). I guess if you feed 16.934MHz crystal into XTI (running 384fs), your DAC will only accept 44.1KHz sampling rate but not 48KHz or 96KHz.

Hi

TCXO have less VLF jitter, but again, that is of NO importance for audio playback

pin 19 contains too much jitter for serious low distortion conversion...........

enjoy