R3267 Series Spectrum Analyzer Operation Manual (Vol.1)
4.5 Phase Jitter Measurement
4-11
4.5
Phase Jitter Measurement
This section describes the phase jitter measurement function that is built in this instrument.
The phase jitter measurement function used in this instrument measures RMS (root mean squared) phase jit-
ters using the equation shown below. Where RMS phase jitter is
∆θ
RMS
[rad], the carrier power is Pc [W] and
the sideband (SSB) power is Pn [W].
In this instrument, carrier power Pc is measured first, power spectrum Pn is measured by summation between
the start offset and stop offset frequencies and then
∆θ
RMS
is calculated from the expression (1). If the range
between the start offset and stop offset frequencies must be divided due to a data acquisition problem, Pn is
the sum of the powers within these ranges.
Figure 4-10 RMS Phase Jitter Measurement Method
4.5.1
Additional Functions
The following two functions are available for improving measurement accuracy. If measurements are taken
with these functions enabled, however, the amount of time required to perform measurements increases, but
the variations between the measurement results are smaller compared to measurements taken when these
functions are disabled.
Signal track function: The center frequency can always be tracked and then set when the carrier frequency
drifts.
Average function:
Performs averaging a specified number of times after dBm data has been converted
into watts when sideband power is measured. To obtain stable measurement results,
increase the number of times averaging is performed.
c
n
RMS
P
P
2
=
∆
θ
(1)
Stop offset
frequency
Start offset
fre
quency
