Configuring Phase Noise

The Phase Noise dialog settings are contained within five tabs: Sweep, RF Path, Spurious, Integrated Noise, and Spot Noise.

 

In this topic:

See Also

Opening the Phase Noise Dialog

Accessing Phase Noise Settings

Using Hardkey/SoftTab/Softkey

Using a mouse

  1. Press Setup > Main >  Phase Noise Setup....

  1. Click Stimulus.

  2. Select Phase Noise Setup....

 

Sweep Tab in dialog help

Noise Type - Selects the noise type from the following selections. The Residual Noise requires 2 port hardware configurations.

Phase Noise -  (Default) - Measures phase noise of a DUT. Select for single channel residual noise measurement when the input and output frequencies of the DUT are not the same. For example, frequency converters.

Residual Noise - Measures the additive phase noise of a DUT. This measurement is set up in the RF Path tab using DUT Input and DUT Output. Select for 2-channel residual noise measurement when the input and output frequencies of the DUT are the same. For example, amplifiers. See Residual Measurement.

Baseband - Measures baseband noise.

Sweep Type - Selects from Log Frequency or Segment Sweep.

XCORR Gain Indicator - Enable the Cross Correlation Gain Indicator. The Gain Indicator is a dark area which is located below the measurement trace. It shows the noise floor level which is reduced by the cross correlation technique. Increasing the number of cross correlation reduces this level.

XCORR Counter - Enable the Cross Correlation Counter. This shows the number of current cross correlation averages for each offset frequency segment of Phase Noise.

Carrier Frequency - Sets the carrier frequency. The range of the phase noise measurement is determined by the start/stop offset frequency which is relative to the carrier frequency.

Enable Search - Search the carrier frequency automatically. This feature is not available in Residual and External mixer measurement. Specify the carrier frequency manually.

Search ONCE - One time execution of the carrier frequency search

Enable Pulse - This feature is available with S96325B Pulsed-RF measurements for SSA-X Signal Source Analyzer.

Pulse Setup- Show the Pulse Setup  dialog.

Start Offset - Sets the start frequency of the phase measurement. This is an offset relative to the carrier frequency to position the measurement about the noise sideband to measure power density in dBc/Hz. For example, if the Start Offset is set to 1 MHz with a carrier frequency of 1 GHz, then the dBc/Hz phase noise measurement starts at 1.001 GHz. The minimum frequency is 0.1 Hz.

Stop Offset - Sets the stop frequency of the phase measurement. This is an offset relative to the carrier frequency to position the measurement about the noise sideband to measure power density in dBc/Hz. For example, if the Stop Offset is set to 10 MHz with a carrier frequency of 1 GHz, then the dBc/Hz phase noise measurement stops at 1.010 GHz. The maximum frequency is 10 MHz. Resolution is 1, 3 step value and 5 MHz, 20 MHz.

RBW Ratio - Sets the resolution bandwidth ratio, which is the specified resolution bandwidth percentage of every half decade offset frequency.

Example:

Start Offset = 1 kHz

Stop Offset = 100 kHz

RBW Ratio = 10%

1 kHz - 3 kHz: RBW = 300 Hz (Same as the second segment)

3 kHz - 10 kHz: RBW = 300 Hz (10% of 3 kHz)

10 kHz - 30 kHz: RBW = 1 kHz (10% of 10 kHz)

30 kHz - 100 kHz: RBW = 3 kHz (10% of 30 kHz)

X Correlation  Factor - Sets the number of times for the cross correlation. S960301xB SSA-X Signal Source Analyzer advanced features is required.  

Fast XCORR Mode - Make the measurement speed faster by optimizing the acquisition. When user XCORR =1, the behavior is same as the normal XCORR mode. The segment xcorr number is different from the normal XCORR mode. The first and second segment xcorr will be xN when user XCORR is N. This is also applied to segments from 1 MHz to 10 MHz. In the other segment, xcorr will be 0.75*X+0.25*X*N to reduce the measurement time. e.g) segment xcorr is 100 @user xcorr=1 will be 125 @user xcorr=2. The max of segment xcorr is 2e8.

Allan Variance - Tau of AVAR and ADEV:

  • Start: Larger value of either 100 ns, or reciprocal value of Stop Offset frequency

  • Stop: Reciprocal value of Start Offset frequency

Maximum measurable offset frequency

The measurable offset frequency is limited by the carrier frequency.  The following graph shows the carrier frequency versus maximum measurable offset frequency.

The blue line shows the measurable offset frequency.

For example, if the carrier frequency of measurement signal is 1 GHz, the measurable offset frequency is up to 300 MHz. The trace shows -200 dBc/Hz over 300 MHz.

The number in parentheses under transition frequency shows the hysteresis range.  For example, the 2 MHz carrier frequency is a transition point between 300 kHz and 1 MHz Maximum offset frequency.

The transition point has the hysteresis range from 1.8 MHz to 2 MHz. This helps to make maximum measurable offset frequency stable when the measurement carrier frequency is around the transition point.

Extension mode

The extension mode (:SENS:PN:SWE:OFFS:EXT ON) can extend the maximum offset frequency as shown by the dotted line for the carrier frequency below.

The measurement result will show harmonics of the carrier in this extension mode.

  

 

Segment Sweep Setup Tab in dialog help

The segment sweep allows you to define independent RBW and Cross correlation factor for each segment.  When you set the start offset of the first segment and the stop offset of the last segment, the segment table is defined automatically. The start/stop offset for each segment and number of segment cannot be changed.

Start Offset - Sets the start frequency of the phase measurement of the first segment.

Stop Offset - Sets the stop frequency of the phase measurement of the last segment.

RBW  - Sets the resolution bandwidth ratio for each segment.

XCORR - Sets the number of times for the cross correlation for each segment.

Import Log Sweep Table - Import the default setting for each segment from the setting in Log sweep.

 

 

Pulse Setup Tab in dialog help

Pulse Period/Pulse Frequency - Select and sets the pulse period or frequency for the phase noise measurement with pulse. The analyzer detects the signal in pulse period and ignore the period while the signal is not detect.

 

RF Path Tab in dialog help

Measurement Type: Phase Noise

Always use Internal Reference - Always use the internal reference despite of the global reference setting.

RF 1/2 Input - Select RF input port for 2 port model.

Auto range -  Check: Attenuator is set automatically by referring the measured carrier power. / Uncheck: Attenuator is set according to Auto setting in the Receiver Attenuator Setting dialog box. This function is disabled in  the External mixer measurement.

Maximum Input Level - Specify the Maximum input level.

[...] - Open the following Receiver Attenuator Setting dialog box.

 

Enable Attenuator Setting - Uncheck: Appropriate attenuator value is set automatically according to the specified Maximum Input Level. / Check: Set the specified attenuator value.

Attenuator - This attenuator values is set when Enable Attenuator Setting is checked.

 

See Measurement using External Mixer for External Mixer Setup.

 

Measurement Type: Residual Noise

See Residual Measurement.

Number of DUT: 1

Number of DUT: 2

Number of DUT - Select 1 or 2 as number of DUT.

Source Internal/External - Select either internal or external for the source. If external is selected, the external source should be configured manually. This setting does not change anything in the analyzer.

Source 1/2 Out - Select configuration of Source inputs. This setting does not change anything in the analyzer.

RF 1/2 Input - Select configuration of Source inputs. This setting does not change anything in the analyzer.

 

Path Delay Compensation:

Path delay difference cause loss of correlation at the phase detector, resulting in imperfect cancellation. Even sub-nano second difference causes large dB error. This function can compensate the error.

Auto - Set the path delay automatically. The path delay is measured at the beginning of each sweep.

Manual - Use the specified Path Delay value.

Path Delay - this value is used in Manual

Measure Path Delay - Click this to measure the path delay for the current setup and input the value in the path delay automatically. Click this after setup your DUT.

 

Measurement Type: Baseband Noise

Always use Internal Reference - Always use the internal reference despite of the global reference setting.

Input  - Select the block capacitor. E505xA has following two block capacitor.

  • AC (LF): Low frequency DC block capacitor 1.410 mF

  • AC (HF): High frequency DC block capacitor 10 uF

Gain -  Select the IF gain from 0 dB to 50 dB at 10 dB step

Discharge DC Block C - Click to discharge DC block capacitor.

 

Source Tab in dialog help

The input is enabled when "Residual" Noise type is selected in the Sweep Tab.

State- Source1/2 Out signal on/off. Actual signal output is changed after Apply is pressed and when sweep starts.

Frequency -  Specify the source frequency. When Source "Internal" in RF Path tab is selected and Frequency is changed, overwrite Carrier frequency entry in Sweep tab.

Power - Specify the source power level.

Resolution - Power entry is updated according to the resolution setting. Normal: 0.5 dB, High: 0.1 dB

 

 

Spurious Tab in dialog help

Show Spurious Table - Enable or disable displaying the spurious table below the trace display.

Trace - Displays trace number(s).

Spur - Displays the spur number(s) per trace.

Offset - Offset frequency.

Power - Power level of the spur.

Jitter - The phase deviation in the time domain.

Table Sort Order - Sets the spurious table sorting by power or by offset.

Select - Select the trace number.

Enable Spur Analysis - Enables and disables spurious analysis search markers. See Spurious Search.

Spur Sensibility - Sets the spurious sensibility value. The default is 3 (3 x standard deviation (sigma)).

Example of Spurious Judgement Using Spurious Sensibility

 

Min. Spur Level - Spurious data larger than this minimum spurious level will be omitted from the spurious data.

 

Omit displayed Spur - Omits all displayed spurs.

Threshold Table... button - Accesses the Threshold Table Setup dialog:

Start Freq - Sets the spurious frequency to use for spurious judgment.

Lower Threshold - Sets the lower threshold to use for spurious judgment.

Upper Threshold - Sets the upper threshold to use for spurious judgment.

 

Example of Spurious Judgment Using Threshold Table

Threshold Data:

Start Freq

Lower Threshold

Upper Threshold

100 Hz

5 dB

15 dB

10 kHz

1 dB

7 dB

 

Spurious Judgment

(A), (E)

For measurement values falling in the range for which no threshold is specified (A), or between the upper and lower thresholds (E), the analyzer determines whether or not they are spurious based on its own determination criteria.

(B)

The analyzer considers the spurious smaller than the lower threshold as non-spurious regardless of its own determination criteria.

(C), (D)

The analyzer considers the spurious greater than the upper threshold as spurious regardless of its own determination criteria.

 

Add button - Adds a row to the Threshold Table Setup dialog below existing entries to define upper/lower threshold at a specific frequency.

Delete button - Deletes the currently selected row in the table.

Delete All button - Deletes all rows in the table.

Save Table button - Saves the table information to a .csv file.

Load Table button - Loads a previously saved threshold table.

 

Omit User Specified Spur - Omits spurs at specified frequencies..

User  Spar Table... - Specifies the frequency point to omit

Add button - Adds a spurious frequency below existing entries.

Delete button - Deletes the currently selected frequency in the table.

Delete All button - Deletes all frequencies in the table.

Save Table button - Saves the spurious frequency table to a .csv file.

Load Table button - Loads a previously saved spurious frequency table.

 

Defaults button - Restores default phase noise settings.

Apply button - Applies setting changes and leaves the dialog box open to make more setting changes.

 

 

Integrated Noise Tab in dialog help

Show Integrated Noise Table - Enable or disable displaying the integrated noise table below the trace display. Integrated noise is the single sideband noise integrated over a measurement bandwidth from a start/stop frequency.

Trace - Displays trace number(s).

Start Offset - This is the same as the Start Offset defined in the Sweep tab.

Stop Offset - This is the same as the Stop Offset defined in the Sweep tab.

Weighting Filter - Displays the weighting filename or None for no weighting.

Integ Noise - Noise over a measurement bandwidth from the defined start/stop frequency.

PM - Phase Modulation measured in degrees and radians.

FM/AM - The FM/AM column displays a value depending on the measurement parameter. When the measurement parameter is Phase Noise , the residual FM (Hz) is shown in the FM/AM column. When the measurement parameter is AM Noise , the percentage of modulation of the carrier is shown in the FM/AM column.

Jitter - The phase deviation in the time domain.

Weighting Filter Setup... button - Accesses Weighting Filter Table Setup dialog. The weighting filters compensate external effects that affect the phase noise in the specified frequency ranges. When the weighting filters are applied, the trace data are corrected by the filter characteristics before the calculation of integrated noise. You must define at least 2 frequencies when using the Weighting Filter.

Add button - Adds a frequency below existing entries.

Delete button - Deletes the currently selected frequency in the table.

Delete All button - Deletes all frequencies in the table.

Save Table button - Saves the weighting filter table to a .csv file. The file should be saved in the following directory: C:\ProgramData\Keysight\Network Analyzer\WeightingFilter. All filters saved in this directory are shown on the drop down list in the Weighting Filter column.

Load Table button - Loads a previously saved weighting filter table.

Select - Selects an existing phase noise trace or allows you to add a new trace. Each trace can have up to four defined ranges. See Displaying Phase Noise Parameters.

Range - Sets the integration range number.

Type - Sets the integration range type of the selected integration range defined as offset frequency from the carrier.

Off - Disables specific range and will not be measured.

Full Span - Enables the measurement bandwidth to be the full offset range defined in the Sweep tab.

Custom - Enables custom-defined start and stop offset range.

Start - Start offset frequency for the integrated noise measurement.

Stop - Stop offset frequency for the integrated noise measurement.

Weighting Filter - Selects pre-defined weighting filter file. Select None when a weighting filter file will not be used.

Defaults button - Restores default phase noise settings.

Apply button - Applies setting changes and leaves the dialog box open to make more setting changes.

 

 

Spot Noise Tab in dialog help

Show Spot Noise Table - Enable or disable displaying the Spot Noise Table below the trace display.

Trace - Displays trace number(s).

Spot Frequency columns - Displays decade edges and/or specified offset spot frequencies.

Select Traces - Select traces for calculating the Spot Noise.

New Traces... button - Add a new trace for calculating Spot Noise.

Define Spot Frequencies - Select the check boxes and enter specific spot frequencies to measure. A trace must be selected.  If Decade Edges is selected, the decade edges will also be measured. Duplicate frequencies between Decade Edges and Spot Frequencies are shown only once.

Decade Edges - Select to measure the decade edges based on the Start Offset and Stop Offset settings defined in the Sweep tab. Deselect to measure only the defined/selected spot frequencies. A trace must be selected.

Defaults button - Restores default phase noise settings.

Apply button - Applies setting changes and leaves the dialog box open to make more setting changes.