Phase Noise and Noise
Measurement
Pengcheng Jia
Nov 21, 2002
Phase Noise
Sth New
Phase Noise Measurement with PSA
(precision spectrum analyzer)
Mode->Phase Noise->LogPlot
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But pay attention to noise floor of the PSA.
You can use noise floor cancellation function
or use the HP11848 Phase noise system
Phase Noise Origins
• 1/f Noise of Semiconductor Transistor
• DC Bias related noise (Shot Noise)
• Thermal Noise from Resistors
Phase Noise Basic
Residual Noise Measurement
20 dB Attenuator
DUT
G=18dB
Source
11848 Phase Noise Interface
+8dBm
R Port
L Port
Power Spliter
+10dBm
Phase Shifter
GPIB Control
0.01Hz
100KHz
3561A Dynamic Signal Analyzer
-
Phase shifter is used to achieve quadrature
Attenuator is used to keep input power at required level
Phase noise of source will not affect residual noise of DUT
when quadrature is achieved
3048 System
11729
11848
3561
Spectrum
Analyzer
Phase Noise Measurements
Phase Noise without amplifiers
Phase noise of a broadband amplifier
3048A Phase Noise Software
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Tiger is the 3048A system controller
Start in MS-Dos Mode
At the command prompt, enter c:\go
Select 13 as the printer type and 0 as the
screen mode. The other settings are user
preference
Now you are at c:\noise\3048>
Run cal.exe for calibration and PN.exe for
measurement
Instrument Addresses
Run PN.exe, Main Menu->System>Instrument
Instrument
Model
Address
FFT Analyzer 3561A
712
RF Analyzer
8567A
718
Signal Srce 1
Signal Srce 2
Down Converter 11729C 706
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(optional for offset from 100K to 40MHz)
(optional)
Getting system ready
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Functional Checks
Quick Check
Performance checks
Calibrations
Read appendix for the time and sequence of
calibration
Run PN.exe
1.Type of measurement->Phase noise without
using PLL (for residual phase noise
measurement)
Start/Stop frequency are the offset
frequency from the carrier
2. Parameters
Input carrier frequency and select detector
Continue…
Instrument control
Select system connections
 Define graph
Configure the displayed graph
 System configuration->Instruments
addresses->Input addresses
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File System
Test file Directory
Save all the configurations for the measurement
 Result file directory
Save the measurement result in this directory
***Always choose this directory before you
save your result, otherwise you only save
the configurations, not the data!!!
 Run Read_res.exe to convert *.res file to
data file which can be used in graph tools.
Go to mishrayork web->document for the file.
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Calibration-theory
Calibration-operation
For the first time, run calibration
Select Derive from measured beat tone
->exit to main menu->New measurement
->”Y”>Select 1KHz as beat-tone (range from 1Hz to
50KHz), input the beat tone signals to the R and L
input of the 11848 interface->Proceed->get
detector constant
Then change connection back and measure PN
 Next time, go to calibration->use current detector
constant
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Measurement
Pay attention to the right and left channel
power level
 For frequency 1.2 G to 18G
L +7->+10dBm
R 0->+10dBm
Keep R channel close to 10dBm, the higher R
signal, the lower noise floor
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Noise Figure
Measurement System
Noise Figure Meter-8970B
Noise Source Driver
CW Generator-8673G
Output power-8dBm
Noise Source - 346C
LO Signal Input
Noise Input
Test Set-8971B
Working Mode:SSB3
From 4-18GHz
Down Convert to
450MHz
Single Side Band Noise
Single MMIC Measurement
Microstrip Probe
Bias For MMIC
Noise Output
Noise Input
MMIC
Combiner Measurement
Bias For MMICs
Noise Source Driver Input
Noise Input
Noise Source
Noise Output
Power Combiner
Heat Sink
Measurement Theory
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Output
Noise Power
No
N2
G
N1
dN 0
dT
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Na
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T1
T2
Noise Temperature-T
The Noise Figure Meter
output noise at two
different noise
temperature
Get the G and Na from
the measurement
Calibrate to eliminate
the affect of the loss of
the cable and
connectors
Measurement Result