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Re: [linrad] Low phase noise LO
- Subject: Re: [linrad] Low phase noise LO
- Date: Mon, 3 Feb 2003 06:04:36 -0500 (EST)
I have built an I/Q system with two diode ring mixers, two very
low-noise op-amps for 14mhz.
Local Oscillator is LC, stabilized with a PIC microcomputer.
Quite cheap and a VERY good performer. Works very nicely with ISA audio
My biggest problems are that many/most newer PCI sound cards are very
Also, some versions of linrad crash?? Still haven't figured out
exactly what is going on. i.e.- lir00-48 works fine, lir00-50 just stops
when I turn on fft3 (I am not using fft2).
just my 2 cents.
It might be useful to start a thread on how to simply measure
performance of linrad type systems.
On Mon, 3 Feb 2003, Edson Pereira wrote:
> I am thinking about building a simple direct coversion IQ receiver and am
> pondering what would be a good local oscilator to use. I will either use a
> diode ring mixer or a Tayloe-like mixer. In both cases, from what I have
> read,the local oscilator should have low phase noise. A DDS would be
> convenient, but it seems that the phase noise is poor. Does any one have
> any suggestions? Would an AD9852 or AD9854 DDS be satizfactory? I don't
> what to make the circuit too complex.
> -- Edson, 7n4ncl