Re-clocking patent : - opinions..

ash_dac · 24th December 2005, 07:53 PM

Hi,

I was trying to find information on the web (as you do on Christmas Eve) about the zero responses that the saa7220 filter has, and came across this reclocking patent.

*look at the pdf versions*

http://www.freepatentsonline.com/5329556.html

http://www.freepatentsonline.com/5465268.html

The circuit of the reclocker seems easy to implement.

Any thoughts ?

Cheers,

Ashley.

Jocko Homo · 24th December 2005, 11:03 PM

Whaddya want to know about the zero in the '7220? Philips used a 3-pole (Butterworth?) analog filter, tuned to 44 kHz. So they added a zero @ 44 kHz in the o/s chip to cancel out one of the poles.

A really dumb idea.................unless you think that ultrasonic birdies going into the I/V stage are ok. They obviously did.

Waiting for the .pdf to load.......back in an hour.......

Jocko

Jocko Homo · 24th December 2005, 11:09 PM

OK.....what I saw looked just like a secondary PLL thingie.............like a gizmo that notorious "clock monger" Guido Tent sells.

Don't see how it was patented.......we were doing that in the telecom world long before Ed Meitner shoved one into a CDP.

Oh.......because he did put one in a CDP. Silly me.

Jocko

ash_dac · 25th December 2005, 08:39 AM

Quote:

Originally posted by Jocko Homo
OK.....what I saw looked just like a secondary PLL thingie.............like a gizmo that notorious "clock monger" Guido Tent sells.

Don't see how it was patented.......we were doing that in the telecom world long before Ed Meitner shoved one into a CDP.

Oh.......because he did put one in a CDP. Silly me.

Jocko

Jocko,

I did some christmas digging.

http://www.belcantosociety.org/pages/dsd.html (see bottom of the page)

http://www.emmlabs.com/

I'm not sure why it was patented.

I had a look at the Wadia site , and saw a list of patents on their products so maybe everyone does it!

Cheers,

Ashley.

ash_dac · 25th December 2005, 09:42 AM

Quote:

Originally posted by Jocko Homo
Whaddya want to know about the zero in the '7220? Philips used a 3-pole (Butterworth?) analog filter, tuned to 44 kHz. So they added a zero @ 44 kHz in the o/s chip to cancel out one of the poles.

A really dumb idea.................unless you think that ultrasonic birdies going into the I/V stage are ok. They obviously did.

Waiting for the .pdf to load.......back in an hour.......

Jocko

Jocko,

Thanks for the information. I was reading a site I found by google
that suggested that the saa7220 inserted some more zero's into the response. But I guess they just put the one in!

Know any 'decent' digital filter chips that are obtainable ? (everything I find is delta-sigma!)

Cheers,

Ashley.

Jocko Homo · 26th December 2005, 12:38 AM

Just the bog standard re-badged NPC stuff with the Burr-Brown/TI logo. It may not be great.......it works.

Jocko

24th December 2005, 07:53 PM	#1
ash_dac diyAudio Member Join Date: Jan 2005 Location: UK	Re-clocking patent : - opinions.. Hi, I was trying to find information on the web (as you do on Christmas Eve) about the zero responses that the saa7220 filter has, and came across this reclocking patent. look at the pdf versions http://www.freepatentsonline.com/5329556.html http://www.freepatentsonline.com/5465268.html The circuit of the reclocker seems easy to implement. Any thoughts ? Cheers, Ashley.

24th December 2005, 11:09 PM	#3
Jocko Homo Banned Join Date: Feb 2002 Location: As far from the NOSsers as possible	Took less time than I thought.......... OK.....what I saw looked just like a secondary PLL thingie.............like a gizmo that notorious "clock monger" Guido Tent sells. Don't see how it was patented.......we were doing that in the telecom world long before Ed Meitner shoved one into a CDP. Oh.......because he did put one in a CDP. Silly me. Jocko

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24th December 2005, 11:03 PM	#2
Jocko Homo Banned Join Date: Feb 2002 Location: As far from the NOSsers as possible	Whaddya want to know about the zero in the '7220? Philips used a 3-pole (Butterworth?) analog filter, tuned to 44 kHz. So they added a zero @ 44 kHz in the o/s chip to cancel out one of the poles. A really dumb idea.................unless you think that ultrasonic birdies going into the I/V stage are ok. They obviously did. Waiting for the .pdf to load.......back in an hour....... Jocko

26th December 2005, 12:38 AM	#6
Jocko Homo Banned Join Date: Feb 2002 Location: As far from the NOSsers as possible	Just the bog standard re-badged NPC stuff with the Burr-Brown/TI logo. It may not be great.......it works. Jocko

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