Hi guys
I'm trying to downconvert the frequency
range : 800MHz to 840MHz to
100Hz to 40MHz with
LO being set at 799.9999MHz.
The mixer that
i'm using is ZEM-4300 minicircuits.
I swept
the RF signal and tried to study the IF signal.
The reading tells me that the IF ZERO has
shifted to 1.1KHz.
As i reduce RF from 840MHz
towards 800MHz with LO maintained constant , IF
frequency reduces respectively from 40MHz towards
100Hz.
With RF at 800.001MHz i expect to
see a 1KHz signal but i see a signal that is closer
to 60Hz(or DC). When i reduce RF beyond this the
IF starts to increase. i.e When RF = 800MHz i expect
to see a 100Hz signal but instead i see 1.1KHz signal.
The signals were observed using a Agilent Spectrum
Analyser and Dynamic Signal Analyser.
This
data tells me that the Zero of the IF spectrum has
shifted to 1/1.1KHz. Can anyone tell me what could
be the issue in this regard.
The power level
of the IF signal has been constant throughout the
spectrum.