thanks..you hit my application!
actually im targeting either diode or bjt based mixer becoz they're
available for me now.
i tried the single-ended bjt mixer..
i set the oscillators around 460khz...with a few hundred of millivolts
peak to peak..
i use the transistor from lm389n audio chip..what i did was to bias it
in its "active mode"
end then single-fed the two outputs from oscillator to the base of
bjt...
the problem is i cant discern the signal from the spectrum..but in the
oscilloscope,its
close to a cliped periodic wave with fundamentals close to the one of
my oscillator frequency...can you help me with another design
configuration with the bjt?

next i tried the diode based but i could hardly get a differnce
frequency..only harmonics though..my arrangement is each input is fed
to a 1k resistor which is then single fed to the negative side of the
diode...any help?or new configuration?

thanks!!