EMRFD Message Archive 10150

Message Date From Subject
10150 2014-07-14 11:27:37 bob_ledoux What Does Tayloe Detector Output Look Like On a Scope?
I'm working on a Tayloe detector front end.

Assume I have a 3253 quad detector followed by two op amps in the classic layout.

A crystal oscillator provides a "received" signal input at 4.000mhz

An SI570 VFO provides the local oscillator at 16.000800mhz.  The VFO provides a square wave with some ringing in the tops.  A74AC74 counter switches the 3253.
The 0 and 180 degree 3253 outputs are fed to one op amp inputs.
The 90 and 270 degree 3253 outputs are feed to the other op amp inputs.
Op amp outputs are not connected together.

Each op amp output is fed to a scope probe.

What should I see on the scope traces? 
Will I see only the audio output or will the LO be present?
What does presence of the 16mhz signal, or its multiple, signify?
What happens if LO voltage is too low?