[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [linrad] Mixer design - comments please
On Tuesday 08 July 2003 3:13 pm, Edson Pereira wrote:
> Hi Bob,
> I understand the need for square levels for the multiplexer. For some
> reason I thought that the AD9852 already had a digital I/Q output. I
> reread the datasheet and found that the chip only provides a comparator.
> -- Edson
Why they didn't put in two comparators I'm not sure - it seems silly to have
only one. I guess it's pretty easy to do IQ in DDS though since all you have
to do is shift your address forward in the sine lookup table a bit.
Well, I'm nearly finalised on the mixer design, and I think I'm going to reuse
most of someone else's board for the DDS. I've also ordered one of those
hugely expensive oscillators... I just have to wait 3 months for that so for
a) 50MHz Xtal osc and use the internal PLL to get the 200MHz ref
or b) 50MHz Xtal osc and some conventional transistor doublers.
This message is intended only for the addressee and may contain
confidential information. Unless you are that person, you may not
disclose its contents or use it in any way and are requested to delete
the message along with any attachments and notify us immediately.
"Transact" is operated by Integrated Financial Arrangements plc
Domain House, 5-7 Singer Street, London EC2A 4BQ
Tel: (020) 7608 4949 Fax: (020) 7608 1200
Integrated Financial Arrangements plc is regulated by the FSA