Agilent Technologies N9010A - Manual (Page 177)

Chapter 18 177
Phase Noise Measurement Application
General Specifications
Description Specifications Supplemental Information
Measurement Accuracy
Phase Noise Density Accuracy
ab
Offset < 1 MHz ±0.50 dB
Offset
≥ 1 MHz
Non-overdrive case
c
±0.50 dB
With Overdrive ±0.60 dB (nominal)
RMS Markers See equation
d
a. This does not include the effect of system noise floor. This error is a function of the signal (phase noise
of the DUT) to noise (analyzer noise floor due to phase noise and thermal noise) ratio, SN, in decibels.
The function is: error = 10 × log(1 + 10
−SN/10
)
For example, if the phase noise being measured is 10 dB above the measurement floor, the error due to
adding the analyzer’s noise to the UUT is 0.41 dB.
b. Offset frequency errors also add amplitude errors. See the Offset frequency section, below.
c. The phase noise density accuracy for the non-overdrive case is derived from warranted analyzer speci-
fications. It applies whenever there is no overdrive. Overdrive occurs only for offsets of 1 MHz and
greater, with signal input power greater than
−
10 dBm, and controls set to allow overdrive. The con-
trols allow overdrive if the electronic attenuator option is licensed, Enable Elect Atten is set to On,
Pre-Adjust for Min Clip is set to either Elect Atten Only or Elect-Mech Atten, and the carrier
frequency plus offset frequency is <3.6 GHz.
The controls also allow overdrive if (in the Meas Setup > Advanced menu) the Overdrive with Mech
Atten is enabled. With the mechanical attenuator only, the overdrive feature can be used with carriers
in the high band path (>3.6 GHz). To prevent overdrive in all cases, set the overdrive with Mech Atten
to disabled and the Enable Elect Atten to Off.
d. The accuracy of an RMS marker such as “RMS degrees” is a fraction of the readout. That fraction, in
percent, depends on the phase noise accuracy, in dB, and is given by 100 × (10
PhaseNoiseDensityAccuracy
/ 20 − 1). For example, with +0.30 dB phase noise accuracy, and with a marker reading out 10 degrees
RMS, the accuracy of the marker would be +3.5% of 10 degrees, or +0.35 degrees.
Description Specifications Supplemental Information
Offset Frequency
Range (Log Plot)
Range (Spot Frequency)
1 Hz to (
ƒ
opt
− ƒ
CF
)
a
10 Hz up to (
ƒ
opt
− ƒ
CF
)
ƒ
opt
: Maximum frequency determined by option
b
ƒ
CF
: Carrier frequency of signal under test
Accuracy
Offset < 1 MHz Negligible error (nominal)
Offset
≥ 1 MHz ±(0.5% of offset + marker resolution) (nominal)
0.5% of offset is equivalent to 0.0072 octave
c
a. Option AFP required for 1 Hz offset.
b. For example,
ƒ
opt
is 3.6 GHz for Option 503.
c. The frequency offset error in octaves causes an additional amplitude accuracy error proportional to the
product of the frequency error and slope of the phase noise. For example, a 0.01 octave frequency error
combined with an 18 dB/octave slope gives 0.18 dB additional amplitude error.