i am new to phase noise measurements and
want to measure phase noise of an
at first i tried direct
measuremnt with a fsek spectrum analyzer from
i quit because my oscillator is quit
better than the lo of the spec
so i want
to try the delay line or autocorrelation method
cause the setup may be much quicker than
refernce source method.
to verify my
measurement result i want to measure the phase
noise of my signal generator ( smt03 r&s)first
setup: signal generator fout=1ghz/ 14dBm
feeding a 6dB power splitter.
splitter via delay line ( approx 8.5ns) to mixer
lo port and the other port of the power splitter
via a variable phase shifter to rf port of the
the if port of the mixer is connected
to a 200khz lowpass followed by a 40dB low noise
if i look at the output of the
amplifier with my oscilloscope i can perfectly
adjust the phase shifter for zero volts DC -
in an application note ( Phase noise and AM
noise measurement in frequency domain from
Lance/Wendell D,.. ) i read that after that i
have to calibrate this setup -
modulate the carrier with 15kHz and choose
fm-deviation to get first null of the carrier (
checked with spectrum analyzer)
do i do next ??
as i understand the
application note : i now have to measure the
15khz sideband at the opamp output and calculate
the calibration factor -
if i do this with
my spectrum analyzer i get approx -50dbm
sideband power and calibration factors of
- can it be right ??
any comments about
the mistake ??