On 7/11/2010 10:50 AM, amdx wrote:
In a direct conversion receiver, does the osc. run at
exactly the same frequency as the received signal?

Assuming the answer is yes;
Is it possible to have a high Q LC front end at the output from the
antenna,
split the signal and feed one output to the rf input of the mixer and feed
the other splitter output to an amplifier and use the amplified signal to
drive the osc input of the mixer?

Simple block diagram of proposed idea;
http://i395.photobucket.com/albums/p...conversion.jpg


Probably not.
You would like to boost the input with a broadband amp, then select the
signal of interest with a local oscillator.

Using the signal itself to select the same signal from dozens of others
would need processing a carrier to provide an LO.
Interesting!

Brian W