EMRFD Message Archive 4091

Message Date From Subject
4091 2010-01-28 05:13:51 n2toh LT5517
I posted something similar in another group, but has anyone here looked at the Linear Technology LT5517?

it's an I/Q demodulator that's designed to receive between 40 and 900 Mhz, but some people have gotten it to work down to 1Mhz. a neat thing about it is that it requires a LO input 2x the desired frequency, so LO leakage should not be a problem. I'm currently making a board to test it with the audio phase shift network on my R2 board so I can hear what it sounds like on the HF bands.
4092 2010-01-28 06:23:10 John Levreault Re: LT5517
Any idea why LT only specifies it down to 40MHz? Many of the specs seem
to get better as the frequencies drop.

de John NB1I

JL


n2toh wrote:
> I posted something similar in another group, but has anyone here looked at the Linear Technology LT5517?
>
>
>
4093 2010-01-28 07:21:23 k5nwa Re: LT5517
They usually specify the range is meant for
operations while having a relatively flat
response. The gain may increase at the lower
frequencies so it would make the response chart
not look flat. In some cases you have internal
caps coupling the signal and they would be too
small to work at the lower frequencies.

I believe this chip uses direct coupling so the
reason could be because it has higher gain at the
lower frequencies. I was looking at getting a couple myself to play with.

At 08:23 AM 1/28/2010, John Levreault wrote:
>
>
>Any idea why LT only specifies it down to 40MHz? Many of the specs seem
>to get better as the frequencies drop.
>
>de John NB1I
>
>JL
>
>n2toh wrote:
> > I posted something similar in another group,
> but has anyone here looked at the Linear Technology LT5517?
> >
> >
> >
>


Cecil
K5NWA
www.softrockradio.org www.qrpradio.com

"Blessed are the cracked, for they shall let in the light."

[Non-text portions of this message have been removed]
4094 2010-01-28 21:11:56 n2toh Re: LT5517
after you get a chance to use the 5517, you may also want to look at the LT5598 it's a direct modulator for use from 5Mhz to 1.6Ghz.

if you need something to mount the 5517 to I have a few extra adapter boards I made.