No Signal!
Compare the circuit simulation shown below with the above.
The first thing we
notice is there is no amplified output!
The blue trace shows the input signal
and the
orange trace shows the output.
In this simulation the signal has been injected into both differential inputs. That is, the
signal appears to go negative and positive on both sides of the differential amplifier
(with respect to ground) at the same time.
Ergo, there is no difference and so
nothing is amplified.
YooFab Differential amplifier for loop antenna No amplified signal
Remember This When Testing:
We must remember the differential nature of this
amplifier when testing. If we forget this and connect a signal generator to both sides of
the differential amplifier, then at best nothing will appear at the output.
In practice the
amplifier is not completely immune to common mode signals and so instead of
there being no signal we should see a comparatively small signal at the output.
ASSEMBLY INSTRUCTIONS
RFLEGO Active Antenna Receiving Loop
page 10 of 66
