Phase Noise and Noise Measurement

Pengcheng JiaNov 21, 2002

Phase Noise

Sth New Phase Noise Measurement with PSA

(precision spectrum analyzer)

Mode->Phase Noise->LogPlotMode->Phase Noise->LogPlot

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 Transistor1/f Noise of Semiconductor Transistor

• DC Bias related noise (Shot Noise)DC Bias related noise (Shot Noise)

• Thermal Noise from ResistorsThermal Noise from Resistors

Phase Noise Basic

- 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

11848 Phase Noise Interface

3561A Dynamic Signal Analyzer0.01Hz 100KHz

GPIB Control

Source

Phase ShifterPower Spliter

DUT

G=18dB

20 dB Attenuator

+8dBm

+10dBm

L Port

R Port

Residual Noise Measurement

3048 System

11729

11848

3561

Spectrum Analyzer

Phase Noise without amplifiers Phase noise of a broadband amplifier

Phase Noise Measurements

3048A Phase Noise Software

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-

>InstrumentInstrument Model AddressFFT Analyzer 3561A 712RF Analyzer 8567A 718 (optional for offset from 100K to

40MHz)

Signal Srce 1Signal Srce 2Down Converter 11729C 706 (optional)

Getting system ready 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. ParametersInput carrier frequency and select

detector

Continue… Instrument controlSelect system connections Define graphConfigure the displayed graph System configuration->Instruments

addresses->Input addresses

File System Test file DirectorySave all the configurations for the measurement Result file directorySave the measurement result in this directory***Always choose this directory before you ***Always choose this directory before you

save your result, otherwise you only save save your result, otherwise you only save the configurations, not the data!!!the configurations, not the data!!!

Run Read_res.exe to convert *.res file to Run Read_res.exe to convert *.res file to data file which can be used in graph tools.data file which can be used in graph tools.

Go to mishrayork web->document for the Go to mishrayork web->document for the file.file.

Calibration-theory

Calibration-operation For the first time, run calibrationSelect 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

Measurement Pay attention to the right and left

channel power level For frequency 1.2 G to 18GL +7->+10dBmR 0->+10dBmKeep R channel close to 10dBm, the

higher R signal, the lower noise floor

Noise Figure

Measurement System

Noise Figure Meter-8970BNoise Figure Meter-8970B

CW Generator-8673GCW Generator-8673GOutput power-8dBmOutput power-8dBm

Test Set-8971BTest Set-8971BWorking Mode:SSB3Working Mode:SSB3

From 4-18GHzFrom 4-18GHzDown Convert to Down Convert to

450MHz450MHzSingle Side Band NoiseSingle Side Band Noise

Noise Source DriverNoise Source Driver

Noise Source - 346CNoise Source - 346C

Noise InputNoise InputLO Signal InputLO Signal Input

Single MMIC MeasurementBias For MMICBias For MMICMicrostrip ProbeMicrostrip Probe

Noise OutputNoise OutputNoise InputNoise Input

MMICMMIC

Combiner MeasurementBias For MMICsBias For MMICs

Noise Source Driver InputNoise Source Driver Input

Noise OutputNoise Output

Noise InputNoise Input

Noise SourceNoise Source

Power CombinerPower Combiner

Heat SinkHeat Sink

Measurement Theory

T1 T2 Noise Temperature-TNoise Temperature-T

OutputOutput

Noise PowerNoise Power

NoNo

N1

N2

Na

GdN

dT 0

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

0

5

10

15

20

25

0

5

10

15

20

25

8 8.5 9 9.5 10 10.5 11

Noise Figure & Gain at Vd=7V

G1(dB)GtdB)

NF1(dB)NFt(dB)NFt*(dB)

Freq(GHz)