Spectrum Analyzer (SA - Option 090)

Configure SA settings

Using front-panel

Using Menus

1. Press Freq

2. Press SA Setup...

1. Click Stimulus

2. Select Freq

3. Select SA Setup...

SA Setup Dialog tab help

Sweep Type - Sets the spectrum analysis sweep type. See Type (Sweep).

Processing

Resolution Bandwidth - Provides the ability to resolve, or see closely spaced signals. The narrower (lower) the Resolution Bandwidth, the better the spectrum analyzer can resolve signals. In addition, as the Resolution Bandwidth is narrowed, less noise is measured by the spectrum analyzer ADC and the noise floor on the display lowers as a result. This allows low level signals to be seen and measured. However, as the Resolution Bandwidth is narrowed, the sweep speed becomes slower.

Auto - Check to couple Resolution Bandwidth to the frequency span in a ratio based on the Span/RBW setting. As the frequency span is narrowed, the Resolution Bandwidth is also narrowed providing increased ability to resolve signals. Clear to uncouple the settings.

Video Bandwidth - Sets the video averaging factor. The averaging operation is applied after the DFT (Discrete Fourier Transform) and before the image rejection. The trace data is smoothed with the method selected by the Video Averaging Type. More smoothing occurs as the Video BW is set lower. However, as the Video BW is narrowed, the sweep speed becomes slower. The Video Bandwidth can be set from 3 Hz to 3 MHz when Auto is deselected.

Auto - Check to couple the Resolution Bandwidth to the Video Bandwidth in a ratio based on the RBW/VBW setting. Clear to uncouple the settings.

Detector Type - A "detector" is an algorithm used to map DFT bins into display buckets. There are typically several DFT bins in a single display bucket, and the detector determines how to translate the multiple DFT values into a single display value.

Peak - Displays the maximum value of all the measurements in each bucket. This setting ensures that no signal is missed. However, it is not a good representation of the random noise in each bucket.

Average - Displays the Root Mean Squared (RMS) average power of all the measurements in each bucket.  This is the preferred method when making power measurements.

Sample - Displays the center measurement of all the measurements in each bucket.  This setting gives a good representation of the random noise in each bucket. However, it does not ensure that all signals are represented.

Normal - Provides a better visual display of random noise than Positive peak and avoids the missed-signal problem of the Sample Mode. Should the signal both rise and fall within the bucket interval, then the algorithm classifies the signal as noise. An odd-numbered data point displays the maximum value encountered during its bucket. An even-numbered data point displays the minimum value encountered during its bucket. If the signal is NOT classified as noise (does NOT rise and fall) then Normal is equivalent to Positive Peak.

NegPeak- Displays the minimum value of all the measurements in each bucket.

Peak Sample - Attempts to determine if the display bucket contains an actual signal, or just noise. If a signal is present, the Peak detector is used, otherwise Sample is applied.

Peak Average - Attempts to determine if the display bucket contains an actual signal, or just noise. If a signal is present, the Peak detector is used, otherwise Average is applied.

Bypass - Check to bypass the Detector Type to view all display points from the DFT. This is only available if the total number of DFT points of the current span can be handled by the display.

Averaging Type - Determines how to compute the video average. When Auto is selected, the optimum type of averaging for the current instrument measurement settings is selected. It averages the magnitude of the DFT bins. Averaging only applies if the video bandwidth is less than the resolution bandwidth.

Voltage - Selects averaging of the detected signal's magnitude and returns the result.

Power - Selects averaging of the detected signal's squared magnitude and returns the square root of the result.

Log - Selects averaging of the detected signal's natural logarithm of the magnitude and returns the exponentiated value of the result.

Voltage Max - Returns the maximum voltage (signal magnitude) measured during the averaging period.

Voltage Min - Returns the minimum voltage (signal magnitude) measured during the averaging period.

Averaging Count - Reads the number of Video bandwidth sweeps that are averaged together. This readout is displayed to the right of the Averaging Type selection (the small "1" shown in the dialog above). It can be read with the remote interface using the SENS:SA:BAND:VID:AVER:COUNt? command.

Settings

Sets the SA (receiver) frequency range when running Linear Frequency sweep type. Use either of the following pairs of settings to determine the frequency range.

Start /Stop - Specifies the beginning and end frequency of the swept receiver range. Start is the beginning of the X-axis and Stop is the end of the X-axis. When the Start and Stop frequencies are entered, then the X-axis annotation on the screen shows the Start and Stop frequencies.

Center /Span - Specifies the value at the center and frequency range. The Center frequency is at the exact center of the X-axis. The Frequency Span places half of the frequency range on either side of center. When the Center and Frequency Span values are entered, then the X-axis annotation on the screen shows the Center and Span frequencies.

Number of Points - Selects the number of trace points on the display. When the Detector is bypassed, the number of display points is read only, it shows the current DFT points to cover the RF span.

Note: When running Segments, the frequency ranges are set by the segment table.

Attenuators

Receiver Attenuation is used to protect the test port receivers from damage or compression. Receiver attenuation causes the applied power at the receiver to be less than the power at the test port by the specified amount of attenuation.

Receiver Attenuators are offered as an option. Learn more.

Type or select independent attenuation values for each test port receiver.

A preference can be set to mathematically offset (or NOT) the reported power at the test port receivers by the amount of receiver attenuation. By default, All PNA models offset the display. Learn how to set the preference.

SA Source Setup tab help

Power On (All Channels)  Check to enable source power for all channels. Only turns power ON if the port State setting is ON.

Port Powers Coupled

• Coupled (checked)  The power levels are the same at each test port. Set power at any test port and all test ports change to the same power level.

• Uncoupled (cleared)  The power levels are set independently for each test port. Uncouple power, for example, if you want to measure the gain and reverse-isolation of a high-gain amplifier. The power required for the input port of the amplifier is much lower than the power required for the output port. A power sweep can also be performed with uncoupled power. Learn more about Setting Independent Port Power.

Source Cells

Name - Lists the test ports through which an internal source is available. If an external source has been configured, it will appear at the bottom of the list.

State

• ON  Source power is ALWAYS ON. Turning ON port 1 will also turn ON port 2 and vice versa. The same is true for port 3 and port 4. Learn about internal second source restrictions.

• OFF  Source power is never ON, regardless of the measurement requirements. Use this setting to prevent damage to a sensitive DUT test port.

• No Control  Available ONLY on external sources. The SA application will NOT control the external source.

Type (Sweep)

CW - The source is set to a CW frequency.

LinFreq - The source is set to sweep from the Start to Stop frequency.

Power - The source is set to a power sweep.

LinF+Pwr - The source is set to sweep from the Start to Stop frequency and power sweep. The order is determined by the Sweep Order selection below.

Segments - The source is set to sweep in frequency sub-sweeps. For each segment you can define independent power levels, IF bandwidth, and sweep time.

Frequency - Click in the cell, then click Edit, to start the Frequency Settings dialog (below).

Power - Sets the power level at the output of the source. Click in the cell, then click Edit, to start the Power Settings dialog (below).

Modulation - Choose from OFF, ON, Pulse. If Enable Modulation Control is enabled, an external modulation source can be controlled (turn on and off its modulation state).

RF Sweep Order

The following settings apply only when LinF+Pwr is selected as the Type of sweep.

Frequency First - Sweep from Start to Stop frequency first followed by a power sweep.

Power First - Sweep power first then sweep from Start to Stop frequency.

Buttons

Path Configuration  Learn more

Pulse Setup  Learn more

External Devices  Learn more

Power and Attenuator  Learn more

SA Coherence Setup tab help

Multitone

The set of Multitone properties enable an enhanced Image Rejection mode that takes benefits of the stimulus test signal knowledge.

If the stimulus test signal is repetitive with a repetition rate of x seconds, it only contains tones that are on a 1/x frequency grid. Example: if the test signal out of an arbitrary wave generator repeats every 1 ms, then it only contains frequencies on a 1 kHz grid (noise is not considered here). We will take this into account here to make the PNA-SA DFT analysis grid landing exactly on the same grid.

Moreover we will use the test signal knowledge to adjust the PNA-SA LO frequencies in order to avoid having 2 tones from the multitone stimulus signal landing at the same location at the PNA IF side. This makes the image rejection process deterministic.

The multitone settings are not working for any tone spacing. Some integer ratios have to be verified between the PNA ADC clock and the multitone period. Adding more constraints on the settings (with harmonic reject parameter or Nyquist reject parameter) can make the coherent multitone mode not available. The last line of the setting dialog indicates if the current multitone settings are valid or not.

Enable multitone image rejection

• Enabled (checked) The other parameters of the Multitone dialog are taken into account. Enabling this mode will set the DFT mode to arbitrary, the RBW shape to No Window, the RBW grid to a set of suitable values, and the list of analysis LOs accordingly. This setting is not compatible with the advanced settings “Force ADC record size” or “Force LO to frequency”.
• Disabled (cleared) Legacy stochastic image rejection mode of the PNA-SA application. When disabled, the window type is set back to what it was before enabling, and the RBW list is also set to the previous setting.

Tone Spacing - The tone spacing of the multitone signal (Hz).

Waveform Period – 1 over the tone spacing. This is the test signal repetition rate (seconds).

Reference Tone – If the multitone grid does not start from 0 Hz, its offset is set here. To make this more convenient, this dialog accepts as well the frequency of any tone of the multitone grid (Hz).

Reject up to harmonic – Set the number of test signal harmonics you want to be protected against. This adds constraints to the list of LOs used to cover the span.

Nyquist protect order – Set the Nyquist protection level. Avoids Nyquist images of the IF higher order signal to fall back on multitone frequencies. This setting can only be set > 1 if the tone spacing of the multitone is not an integer divider of 100 MHz.

Vector Averaging – Average ADC samples by the specified number (≥1) in FPGA memory before the DFT processing. For example, if an ADC record size of 1,000 samples is acquired and Vector Averaging is set to 2, then 1,000 samples will be averaged to 1,000 samples and the result (1,000 samples) will be stored in FPGA memory. In other words, we acquire 2,000 samples form ADCs and send 1,000 averaged samples to the next processing stage. Vector averaging helps to reduce noise and increase dynamic range. However, this feature should only be used when the stimulus frequencies are known and coherent with the current ADC record size. A value of 1 means no averaging. Note this feature behaves like ADC Stacking+1. The maximum vector averaging value is 65536 or below. It depends on the RBW and the decimation.

Check box- Check to enable the ADC sample Vector Averaging to be specified manually.

Note: Vector Averaging and Video Bandwidth averaging cannot be set together. When enabling vector averaging, if the coherent mode is enabled then Video Bandwidth is turned off . The ADC Record Size x Vector Averaging must be ≤ 64 Mega Samples (or ≤ 32 Mega for some multiple receivers configurations).

Note: Vector Averaging is a great averaging method when Coherent Multitone mode is enabled. We recommend increasing it in Coherent Multitone mode instead of reducing the RBW to reduce the noise floor.

Note: Coherent mode (and Vector Averaging too) will work well if and only if the signal source and the PNA have their reference clocks synchronized. This is usually done by the mean of a 10 MHz reference BNC cable between the signal source and the PNA.

Note: Vector Averaging is also known as Stacking. In fact, Vector Averaging = stacking +1.

Data Display

• Show All - Legacy behavior, shows the noise or the spurious between the tones. Note the RBW shape for multitone (No Window) and the deterministic image rejection make the noise or the out of grid spurious amplitude values not accurate.
• Zero the non-tones - All the span frequencies that are not on the multitone grid have their amplitudes set to -200 dBm before correction. This makes band power marker measuring only the power for multitone frequencies, and not the noise power.

Multitone settings are valid – Indicates if the current multitone settings are valid or not.

Advanced Settings Dialog tab help

Properties

RBW Shape - Selects the digital filter (window) to apply to the time domain IF signal. The filter effectively "shapes" the signal before application of the DFT to help avoid discontinuities which add unwanted frequency content to the spectrum. Each filter has its own advantages and disadvantages.

Gaussian - Selects a Gaussian window. The Gaussian window has good frequency separation and moderate amplitude accuracy. This window provides higher dynamic range because it has much lower side lobes. It is used for general-purpose measurements and when high dynamic range is required.

Flat Top - Selects the flat top window for amplitude measurement of sinusoidal frequency components. The flat top window has moderate frequency separation and excellent amplitude accuracy. It is typically used for narrowband signals when measuring the amplitude of a particular frequency component with greater amplitude accuracy.

Kaiser - Selects the Kaiser window which is an approximation of a Slepian window using Bessel functions. This window has a relatively high dynamic range and is similar to the Blackman window.

Blackman - Selects the Blackman window. This window has a relatively high dynamic range and is similar to the Kaiser window.

No Window - The No Window selection does not modify the time-domain data in any way before applying an DFT. This selection is very fast but may yield a significant number of side lobes in the frequency domain because of spectral leakage. This selection has a rectangular shape and does not attenuate any portion of the time record.

Image Reject Type - Sets the minimum number of distinct DFT acquisitions to use when computing an actual signal. As the number of DFT acquisitions increases from the None, LO Low setting to the Max setting, an increased number of erroneous signals are eliminated. Therefore, the Better and Max settings provide the highest confidence that what remains are actual signals, at the expense of slower measurements.

None, LO High - Selects 1 acquisition with the LO higher than the receiver frequency.

Note: Selecting None, LO High with a span reaching the high end frequency of the PNA is not possible. See SA Warning Messages.

None, LO Low - Selects 1 acquisition with the LO lower than the receiver frequency.

Note: Selecting None, LO Low with a span reaching the low end frequency of the PNA is not possible. See SA Warning Messages.

Min - Selects 2 acquisitions.

Normal - Selects 4 acquisitions.

Better - Selects 6 acquisitions.

Max - Selects 8 acquisitions.

Image Reject Strength - Sets the image rejection strength. During the image rejection process, several LO acquisitions overlap at the same RF frequency (depending on the Image Reject Type). As a result, different RF signal values can be returned. This feature sets the acceptable power differences between measurements performed with different LOs in determining actual signals. Possible values are Weak, Normal, Strong. Weak accepts more difference between measurements, and strong less difference.

RBW/VBW - Sets the ratio of Resolution Bandwidth to Video Bandwidth when the Video Bandwidth is in Auto mode.

Span/RBW - Sets the ratio of Span to Resolution Bandwidth when the Resolution Bandwidth is in Auto mode.

CF Step Size - Manually sets the amount Center frequency change that occurs when ▲|▼ is clicked (next to the value).

Auto - Each press of the ▲|▼ arrows increments or decrements the Center frequency by 5% of the current frequency span.

Occupied BW search min - Sets the minimum search frequency to use during an Occupied BW search measurement. Power below this frequency is ignored. See Occupied BW Ratio for information about setting up this measurement type.

DC Sources

DC source control allows the spectrum to be measured at multiple DC source settings.

Enable DC Outputs - Enables all DC source outputs that are turned ON in the DC Source dialog. This same selection is found in the DC Source Dialog.

Enable DC Sweep - Enables the DC sources to sweep between their start and stop voltages. If not selected, then the DC sources will be set to their start voltages.

DC Sources... - Configure internal DC sources. Learn more.

Number of DC levels - Defines the number of voltage levels in the DC sweep.

The following settings apply to the measurement loop order. The SA may be programmed to loop through a series of spectrum measurements at multiple RF source frequencies, multiple RF source powers, and multiple DC voltages. These radio buttons determine whether the DC sources are swept before the RF power and frequencies are swept, or whether the DC sources are swept after the RF power and frequencies are swept.

Sweep Order

DC before RF - Sweep through each DC voltage step first then sweep through the next frequency.

RF before DC - Sweep through each frequency step first then sweep through the next DC voltage.

Advanced >> button - Accesses the IF, Trigger, Processing, and ADC & LO, and Data dialogs.

IF Dialog tab help

IF Gain

Auto - Selects the appropriate amount for gain versus RF frequency bands for each receiver IF Path.

Or select a specific amount of gain (in dB) for IF receiver paths.

Couple all IF paths - When checked, all receivers assume the same setting. When cleared, each receiver can assume an individual setting.

IFConfig - Accesses the IF Path Configuration dialog. Learn all about IF Path Configuration.

IF Bandwidth

ADC Filter - Selects between a narrow and wide IF filter anti-aliasing path.

Narrow 11MHz - Selects the ADC 11 MHz IF filter path. A warning message will appear if the Narrow IF filter path is selected and the Resolution Bandwidth is > 1 MHz. See SA Warning Messages.

Wide 38MHz - Selects the ADC 38 MHz IF filter path.

Auto - Check to automatically set the ADC Filter setting based on the ADC Sampling Frequency.

DFT Bandwidth Auto - Enables the default values for DFT bandwidth.

With Auto checked, the default values are:

Narrow - 1 MHz to 10 MHz

Wide - 1 MHz to 34 MHz

With Auto unchecked, the values can be entered manually. The ranges are:

Narrow - 500 kHz to 11 MHz

Wide - 500 kHz to 44 MHz

Trigger Dialog tab help

Trigger

Advanced Trigger Modes - Check to enable a measurement trigger based on the ADC Level or a period of time.

ADC Level - Initiate a measurement trigger event whenever the ADC level of any of the receivers at work is greater than this specified value (0 ≤ ADC Level ≤ 1683). A level of 100 is recommended as a default value. The ADC level is an uncalibrated value that reflects signal peak amplitude. It will detect RF energy only within the current IF bandwidth, so it would make sense to use this feature associated with a Forced LO value or a narrow SA span.

Periodic Counter - Initiate a measurement trigger event based on the specified period. For example, if Periodic Counter is set to 1,000,000, then an acquisition occurs every 0.01 sec (1,000,000 x ADC Sampling Frequency (10 nsec)).

Trigger... - Accesses the Trigger dialog for setting up triggering.

Pulse Gen Config... - Accesses the Pulse Generator Setup dialog for setting up pulse measurements.

Hold - The channel accepts NO trigger signals.

Single - The channel accepts ONE trigger signal, then goes into Hold.

Continuous - The channel accepts an infinite number of trigger signals.

Processing Dialog tab help

Processing

DFT Type - Sets the DFT record size type. The types include:

Power of 2 - Sets the DFT record size to the next power of 2 greater than or equal to the current ADC record size. This is the fastest DFT processing available; the power of 2 record size allows for very efficient computation shortcuts (also known as the FFT algorithm).

Fastest - Sets the DFT record size as close as possible to the ADC record size (larger or equal) while optimizing processing speed.

Optimized Radix - Sets the DFT record size to the minimum integer number larger or equal than the ADC record size that can be decomposed with 2,3,5,7,11,13 radixes (also known as the 13-smooth numbers). The Intel CPUs have shard-coded trigonometric values for 2, 3, 5, 7,11, 13 fractional angles; the DFT code takes benefits from that for efficient DFT processing.

Arbitrary - Sets DFT record size equal to the ADC record size. If the current ADC record size is a large prime number, then the DFT can be very slow. Sometimes, the record size will be increased more than the minimum number required to match the 13-smooth condition, if the whole processing of the sweep is faster with a record size that has a faster DFT time. There is a trade-off here: increasing the record size to speed up the DFT will increase the amount of data to process for the further steps of the SA processing (image rejection, detection).

Additional comments:

There is a given ADC record size that gives a given RBW (for a given window type), the RBW evolves as 1/ADC record size. If the DFT record size must be greater, depending on the DFT mode, some zeros will be added to the ADC record size. This is the difference that can be noted between the ADC record size and the DFT record size on the Advanced Processing dialog.

When running the coherent mode of SA, the Arbitrary mode will always be selected, to make sure the DFT bins frequencies exactly land on the coherent signal tones.

The Power of 2, Optimized Radix, and Fastest mode have the same behavior regarding the RBW setting: These 3 modes are increasing the ADC record size to the next best match. This is more sensitive with Power of 2 mode, as the density of available ADC record size is sparse.

The Power of 2 mode makes the SA computation behave exactly like some tools based on FFT processing; this is a use case of this mode. The other use case is to get the fastest processing time that can be useful for intensive spurious search measurements. The penalty is the small number of RBW values available.

The Optimized Radix mode is currently the default mode, this is the one that gives the most accurate RBW setting. The Fastest is to be tried if speed matters for a given non-coherent SA setting.

For example: running 100 kHz RBW with Gaussian filter, the ADC record size must be 1988 samples. Here are the DFT lengths for the different algorithms:

• Power of 2: 2048

• Fastest: 2048

• Optimized Radix: 2000

• Arbitrary: 1988

Display image reject traces - Check to display the data acquired by each LO. The minimum number of meaningful traces is determined by the "Image Reject" setting (described in the Advanced dialog above).

About Image Reject Traces

These traces display the spectral content of the measured signal for each LO frequency used in the acquisition. The number of ImageReject traces you want to look at is tied to the 'Image Reject' setting. For example, 'Normal' setting is at least 4 ImageReject traces, and 5 more generally.

This function is intended to be used as a diagnostic tool if something looks suspicious.

Note: Mixer calibration and user calibration are not applied to the image rejection traces, thus the amplitude readout value is not accurate.

Info

This dialog provides with a list of values from the current sweep. When settings affecting these values are changed, the displayed values are not updated automatically and will become grayed out. To update the values, either close then open this dialog, or move to another dialog and go back. The analyzer must be sweeping to update the values.

Acq. Time for 1 LO - Displays the LO acquisition time which is the ADC Record Size x ADC Sampling Frequency (10 nsec or 40 nsec) x (1 + Stacking) x (Video Averaging Coefficient.

Span LOs count - Displays the number of LO acquisitions determined by the Image Reject selection and the span.

Span LOs count - Displays the number of LO acquisitions determined by the Image Reject selection and the span. When settings affecting this value are changed, the displayed value is not updated automatically and will become grayed out. To update the value, either close then open this dialog, or click on the Update Info button. The analyzer must be sweeping to update values.

Span bins count - Displays the current span DFT bin count, the number of DFT points processed across the total RF span. When the Detector is bypassed, this is the number of points that are sent to the display.

DFT resolution - Displays the DFT resolution in Hz.

DFT record size - Displays the current DFT record size.

ADC record size - Displays the ADC record size value.

ADC & LO Dialog tab help

ADC

ADC Sample Frequency - Select between 100 MHz and 25 MHz.

Auto - Check to automatically set the ADC Sampling Frequency.

Enable FIR for 25 MHz - Enables the FIR filter for 25 MHz decimation: reduces the noise floor.

Dithering - Check to allow ADC dithering to average out the characteristic "stair steps" produced during the ADC conversion process.

Force ADC record size - Sets the ADC record size which is dependent on the Resolution Bandwidth and ADC Sampling Frequency:

Check box - Check to enable the ADC record size to be specified manually. Doing so sets the resolution bandwidth. The size range is 64 Samples to 32 or 64 MegaSamples depending on the selected receivers. The DFT size will be recomputed accordingly to the DFT Type setting. When not checked, the value displayed is the current ADC record size. This feature is not compatible with Coherent Multitone mode.

Stacking - Stack ADC samples by the specified number (≥1) and store result in memory. For example, if an ADC record size of 1,000 samples is acquired and Stacking is set to 1, then 1,000 samples will be added to 1,000 samples and the result (1,000 samples) will be stored in memory. In other words, we acquire 2,000 samples form ADCs and send 1,000 stacked samples to the next processing stage. Stacking helps to reduce noise and increase dynamic range. However, this feature should only be used when the stimulus frequencies are known and coherent with the current ADC record size. A value of 0 means no stacking.

Check box- Check to enable the ADC sample stacking to be specified manually.

Note: Stacking and Video Bandwidth averaging cannot be set together; Video Bandwidth has precedence. The ADC Record Size x (Stacking + 1) must be ≤ 64 Mega Samples.

Note: Stacking is a great averaging method when Coherent Multitone mode is enabled. We recommend increasing the stacking in Coherent Multitone mode instead of reducing the RBW in order to reduce the noise floor.

Multiple Recording - Check to allow the ADC Record Size to be divided and acquired in smaller "chunks" and also specify a wait period between these acquisitions.

Chunk Size - Sets the size to acquire the ADC record in smaller "chunks". For example, if the ADC Record Size is 2048 and the Chunk Size is set to 256, then the ADC record is acquired in 8 chunks (1 ≤ Chunk Size ≤ ADC Record Size).

Chunk Period - Set the period to wait between ADC record chunks.

Note: This feature is compatible with Coherent Multitone mode.

LO

Randomized LO - Check to allow dithering of the LO values used when taking a sweep. Allowing randomized LO makes it less likely that erroneous signals will appear in the final measurement.

Force LO to Frequency - Sets the LO to a specified frequency. This check box can only be set if Image Reject is set to None, LO Low or None, LO High.

Check box - Check to enable the LO frequency to be specified manually.

Data Dialog tab help

This Data page is intended to give access to the SA engine data after the Fourier transform, and before the display detection data reduction (peak detector…). In other words, access to the DFT image rejected frequency points. It is still possible to output data from a SA channel with the legacy PNA data output functions, but these functions are tied to the number of display points. Note that the markers, with special peak search, band power, noise power, and occupied band modes are another convenient way to grab data from a SA channel.

Data Format -

Float LogMag (dB) - Sets the data format to log magnitude in dBm.

Float LinMag - Sets the data format to linear magnitude in volts.

Integers - Sets the data format to Packed Integers (each value is a short 16 bit integer, the equation to compute the dBm value is: dBm = Xshort/200.0 - 36.165

Export receivers - Select the data to export from a specific receiver or all receivers.

Don't save data below threshold - Set data level threshold mode and threshold level in dBm. For text file output with verbose mode, only the frequencies with power greater than this threshold setting will be written to the file.

DFT bins count - Displays the current DFT bin count, the number of DFT points processed across the total RF span. When the Detector is bypassed, this is the number of points that are sent to the display.

Receivers count - Displays how many receivers are currently being exported. The number here can be less than the number of receivers specified in Export Receivers, if some of them at not selected in the channel.

Export to binary file - Set data to be exported to a binary file. Data is not exported until the next new sweep occurs.

Export to text file - Exports data only. Data is not exported until the next new sweep occurs.

Verbose mode - Exports frequency and data. Data is not exported until the next new sweep occurs.

Erase files each new sweep - Selecting this option will erase the data after each sweep. If this option is not checked, the data from each sweep will continue to be appended to the output data file which can create a very large file size (and fill the disk, with many unwanted consequences).

File name prefix - The receiver selected in Export receivers will be appended to the prefix name specified in this field with either ".txt" if a text file is exported or ".bin" if a binary file is exported. For example, if C:\Temp\SA_DATA_OUT is entered into the File name prefix field and the "B" receiver data is exported to a text file, the data will be exported to a file called SA_DATA_OUT_B.txt.

Record size (bytes) - This is the byte size of binary data output.

Export markers - Adds marker data to the text file (*.txt) output.

Export to FIFO buffer - Exports data to the FIFO (First-IN, First-OUT) data buffer. FIFO is a circular buffer that allows very fast Read-Write access.

Export to shared memory - Exports data to shared memory (Microsoft Windows feature) which is the fastest way to transfer data between applications. The application that is retrieving data has to register itself to Microsoft Windows with the same share name.

Share name - Assigns a specified name to the shared data.

(Source) Frequency Settings dialog help

In the SA Setup Source Tab (above):

> When (Sweep) Type = CW, set the CW Frequency.

> When (Sweep) Type = Linear, the following dialog appears:

Settings

Sets the source frequency range. Use either of the following pairs of settings to set the frequency range.

Start /Stop - Specifies the beginning and end frequency of the swept range.

Center /Span - Specifies the value at the center and frequency range.

Source Number of Steps - Sets the number of steps the source will make across the specified source frequency range.

SA Sweeps / Source Step - Sets the number of SA (receiver) sweeps for each Source Step. This setting is common to all sources.

(Source) Power Settings dialog help

In the SA Setup Source Tab (above):

> When (Sweep) Type = CW or LinFreq, set the power level.

> When (Sweep) Type = Power or LinF+Pwr, the following dialog appears:

Settings

Sets the source power range. Use either of the following pairs of settings to set the power range.

Start /Stop - Specifies the beginning and end power of the swept range.

Center /Span - Specifies the value at the center and power range.

Source Number of Steps - Sets the number of steps the source will make across the specified source power range.

SA Sweeps / Source Step - Sets the number of SA (receiver) sweeps for each Source Step. This setting is common to all sources.

How to select and configure Measurement Parameters

Using front-panel

Using Menus

1. Press Meas

2. Select a parameter

1. Click Response

2. Select Measure

3. Select a parameter

SA Markers

The following marker-related features are unique to SA.

Marker => SA

This feature is supported in Standard, SMC or Swept IMD measurement classes (channels) ONLY. In this section, these are called NA channels.

On a standard channel with a marker residing on a trace in an NA channel, Marker=>SA creates a new SA channel in full frequency span. Refer to the following for swept IMD and SMC:

Swept IMD: span = 10 * delta frequency

SMC: SA channel uses receiver frequency range

A marker is created on the trace at the same frequency as the NA channel marker. This is a quick way to see the frequency spectrum of the NA channel at a specific frequency.

• The same source that is used for the trace in the NA channel is turned ON in the SA channel in CW mode at the marker frequency.
• The same receiver that is used for the NA channel is used for the SA channel.
• For each new NA channel, a new SA channel is created. Subsequent markers in the same NA channel use the same SA channel.
• In general, Marker => SA creates a new measurement on the SA channel only if the measurement does not already exist. For example, if a marker is used on an S11 measurement in a standard channel, Marker => SA creates a measurement using test receiver "A" with port 1 as the source. If Marker => SA on an S12 measurement is then performed, the same test receiver "A" is used except that port 2 becomes the source. In this case, a new SA trace will not be created.

How to use Marker =>SA

With a marker residing on a trace in a standard channel...

• With a mouse: Right-click on a marker, then Marker Functions, then Marker=>SA.
• With a keyboard: With the relevant marker active (selected), Alt+M, F, A.
• Without mouse or keyboard: With the relevant marker active (selected), Press Marker, [Marker Functions], then [More], then [Marker=>SA].

Band Markers

The following two marker types provide a readout of the total power or noise within a selectable frequency span.

These markers can be used with marker tracking ON. Learn more.

• Band Power - These markers provide a readout of the total power within a specified frequency span.
• Band Noise - Same measured power, but mathematically normalized to a 1 Hz bandwidth in the same manner as a Noise Marker. Learn more.

Note: If a Band Power or Band Noise marker is selected, Discrete mode is turned OFF to allow precise measurements over the desired frequency range.

The span is marked by vertical dotted lines that appear on either side of the marker. The marker's y-axis value is set to the measured power value.

If a Band Power or Band Noise marker is in Delta mode, the difference between the Band Power or Band Noise marker and the reference marker is displayed with a leading delta symbol.

How to select Band Power or Band Noise

1. Press Search, then [Search...].
   The following dialog appears:
   
2. Select an existing marker.
3. For Search Type, select Band Power or Band Noise.
4. For Span, enter a frequency span over which the marker will report power or noise.
5. Click OK.

If a Band Power or Band Noise measurement cannot be made, the marker readout will display -999 dBm (for Band Power), or -999 dBm/Hz (for Band Noise). There are two reasons why this may happen:

1. The band span (from marker frequency – span/2 to marker frequency + span/2) is outside the frequency range of the channel.
2. The Band Power or Noise marker was created while the channel was in Hold mode. At least one sweep must be taken after creating such a marker. The marker can be moved taking a sweep while in Hold mode. However, the marker readout will not change. To update the marker readout to the new marker location, a re-sweep is required.

Occupied BW Ratio

The Occupied BW Ratio is the frequency band in the measurement that contains a specific percentage of the total power in the measured frequency span. The marker readout provides the occupied band center frequency, percentage of the band span to measure, and the occupied band power. See also Occupied BW search min for setting the minium frequency to start a search.

The span is marked by vertical dotted lines that appear on either side of the marker indicating the percentage of span. The marker's y-axis value is set to the measured power value.

How to select Occupied BW Ratio

1. Select one of three ways to enable Occupied BW Ratio:
   1. Press Search, then [Band Power], then [Occupied BW ON].
   2. Press Marker, then [Properties], then [Band Power], then [Occupied BW ON].
   3. Press Search, then [Search...]
      The following dialog appears:
      
2. If the Marker Search dialog is used, perform the following steps:
   1. Select an existing marker.
   2. For Search Type, select Occupied BW Ratio.
   3. For Percent, enter a percentage of the band span to search.
   4. For Search Domain, either select Full Span (default) or define a User Span by selecting User N then specifying the Start and Stop frequencies.
   5. Click OK.