The Mode menu defines the properties of the physical and logical (balanced) test ports, configures the source signals and the receiver, and provides special measurement modes.
Port Config... calls up a dialog to define the properties of the test ports, the source and the receiver.
Harmonic Distortion opens a submenu providing arbitrary harmonic measurements.
Mixer Mode opens a submenu to control the measurement of the mixing products generated by an external mixer that is supplied with two independent RF signals.
Virtual Transform opens a submenu to define the parameters of a virtual matching network to be embedded into/deembedded from the measurement circuit for a DUT with single ended or balanced ports.
Alternating Sweeps activates or deactivates the operating mode where the analyzer performs only one partial measurement per sweep.
Spurious Avoidance opens a submenu to define the relative position of the local oscillator (LO) relative to the RF input signal.
ALC (All Chans) enables or disables the Automatic Level Control for all channels.
Low Phase Noise reduces the phase noise of the source signals.
The Port Configuration dialog defines the properties of the test ports and configures the source signals and the receiver.
The table in the Port Configuration dialog contains the individual test port properties. Each table row corresponds to one logical or physical port; the number of rows is equal to the number of test ports of the analyzer.
Many measurement tasks can be performed with default port settings. Consequently the Port Configuration dialog does not show all columns in its default configuration. Use the Displayed Columns button to customize the table and display or hide columns.
Measured Ports (Meas/Group)
The ports that can be used for the measurement (as selected in the Balanced and Measured Portsdialog) are indicated in the first column of the Port Configuration table (Meas). The selected ports are used for the calculation of derived (mixed mode, Z, Y) parameters; they can be source ports and/or receive ports.
A measured port can be configured as a pure receive port by selecting RF Off in the Source section.
If one or more port groups to be measured are defined in the Define Measured Portstab of the Balanced and Measured Ports dialog, then the column header changes from Meas. to Group and the column shows the group names (capital letters).
The settings are grouped together in four sections:
Logical Port shows the properties of the balanced ports after they have been defined in the Balanced and Measured Ports dialog. This section is hidden if no balanced ports are defined.
Physical Port shows and/or defines the properties of the physical (unbalanced) ports of the analyzer.
Source shows and/or defines the generator settings at each physical port of the analyzer.
Receiver shows and/or defines the receiver settings at each physical port of the analyzer.
Below the table, two buttons open additional dialogs:
Displayed Columns... opens a dialog to customize the port configuration table and display or hide columns.
Balanced and Measured Ports... opens a dialog to select a balanced port configuration and define the reference impedances at the ports.
The dialog contains the following additional controls:
If Same Connector Type at All Ports is active, the connector types at all ports (but not their gender) are always adjusted to the current selection in the Connector column.
Measure "a" Waves at selects the analyzer frequency for the measurement of the reference waves an. Depending on the measured quantity, the reference waves can be measured at the receiver or at the source frequency.
Freq Conv Off disables all frequency-converting modes, i.e. it resets all port frequencies to the basic channel frequency and disables the Harmonics and the Mixer measurement (with option R&S ZVA-K4).
Remote control:
[SENSe<Ch>:]CORRection:COLLect:CONNection:PORTs ALL | SINGle [SENSe<Ch>:]FREQuency:CONVersion:AWReceiver[:STATe]
Defines the properties of the logical (balanced) ports defined in the Balanced and Measured Ports dialog. To display this section, at least one balanced port configuration must be defined and Logical Ports – Ref Impedance must be selected in the Displayed Columns dialog.
# is the port number of the logical port. This number is independent of the physical port numbers and of the ports that are combined to form a balanced port.
Ref Impedance shows the complex reference impedances of the ports.
Reference impedance settings
The default reference impedance for a physical port is equal to the reference impedance of the connector type assigned to the port but can be defined as an arbitrary complex value (renormalization of port impedances). By changing the reference impedance, it is possible to convert the measured values at 50 W (75 W) into values at arbitrary port impedances.
For balanced ports it is possible to define separate complex reference impedances for differential and for common mode.
The default values for the balanced port reference impedances are derived from the default reference impedance of the physical analyzer ports (Z0 = 50 W):
The default value for the differential mode is Z0d = 100 W = 2*Z0.
The default value for the common mode is Z0c = 25 W = Z0/2.
SENSe:PORT<phys_port>:ZREFerence <real> [,<imaginary] SENSe:LPORT<log_port>:ZCOMmon <real> [,<imaginary] SENSe:LPORT<log_port>:ZDIFferent <real> [,<imaginary]
Shows and/or defines the properties of the physical (unbalanced) ports of the analyzer.
# is the test port number of the analyzer as shown on the front panel. External generators and power meters configured in the System Configuration dialog are also shown in the list of physical ports.
Instrum. shows the network analyzer type (e.g. ZVA8, ZVA24). The types of external generators and power meters are also displayed in this column.
Connector opens a drop-down list to select the connector type An (f) behind the connector type denotes female connectors, an (m) denotes male connectors. Symmetric (sexless) connectors (e.g. PC7) are not labeled. User-defined connectors can be added or removed in the Available Connector Types dialog, which is opened from the Channel –Calibration –Calibration Kits dialog. at the port and its gender. If Same Connector at All Ports is active, the connector types at all ports (but not their gender) are always adjusted to the current selection.
Ref. Impedance shows the adjustable complex reference impedances of the physical port. If a balanced port configuration is active the reference impedance settings for all ports are displayed in the Logical Port section.
To perform a system error correction, the physical port must be available as a source and receive port. This condition is met if it is selected as a measured port in the Balanced and Measured Ports dialog (Meas is on).
To perform a system error correction, it is necessary that:
the physical port is available as a source port
both the measurement and the reference channel at the port can be measured
These conditions are met with the Port Configuration settings listed below.
Section
Parameter
Value
Meas
On
on
Source
Perm
off
Receiver
LO a
LO b
[SENSe<Ch>:]CORRection:COLLect:CONNection<port_no> [SENSe<Ch>:]CORRection:COLLect:SCONnection<port_no> [SENSe<Ch>:]CORRection:COLLect:CONNection:PORTs ALL | SINGle SENSe:PORT<phys_port>:ZREFerence <real> [,<imaginary]
Shows and/or defines the RF generator settings for each physical port of the analyzer and for each external generator. No source settings are provided for external power meters.
Most of the settings in this section require option ZVA-K4, Arbitrary Generator and Receiver Frequencies.
RF Off switches the RF signal source at the port off (box checked) or on. Dependencies: The column is disabled (grayed) while the RF power is switched off globally for the active channel. The settings are restored as soon as the RF power is switched on again. RF Off and Meas are independent from each other: While the RF power is switched off, the port is not necessarily excluded from the measurement, it can still be used as a receive port. On the other hand, an excluded port (Meas = Off) can still be used as an RF signal source.
The source must be switched on to perform a system error correction or a source power calibration for the source port.
Gen qualifies whether the RF signal source at the port is switched on for all partial measurements (box checked, permanent signal source) or only for the partial measurements that require the port as a drive port. Dependencies: Gen has no effect unless the RF source at the port is switched on (RF Off is not checked). A port which is excluded from the measurement (Meas = Off) can still be used as a permanent RF signal source. If Gen is on, then the source frequencies at port 1 and 2 and at port 3 and 4 are coupled; see note on coupled test ports below.
External generators
An external generator always represents a permanent signal source that is switched on for all partial measurements. Gen qualifies whether or not the generator is actually available as a signal source in the test setup.
The analyzer provides two alternative ways of selecting a generator as a signal source:
Gen: On in the Port Configuration dialog, especially if the generator is not assigned to a particular measured quantity or drive port.
Selection as a source for a particular measured quantity or for a power calibration, see e.g. More Wave Quantities.
The two selection mechanisms are independent from each other.
Permanent vs. intermittent RF signal source
Switching on the signal source permanently eliminates the power settling times of the DUT but may introduce measurement inaccuracies, e.g. due to crosstalk between two ports. Therefore, the parameter must be switched off to perform a system error correction.
Frequency opens an input box to define a port-specific stimulus frequency range (for frequency sweeps) or CW frequency (for power, time and CW Mode sweeps). In the default configuration the stimulus parameters (sweep range, CW Frequency) are used. The result is displayed in the Frequency Result column. A red Frequency field indicates that the hardware limits are exceeded, e.g. if the default sweep range of the analyzer is beyond the frequency range of the external generator.
Coupled test ports
Test ports 1 and 2 and test ports 3 and 4 are supplied by a common generator (see ZVA block diagrams in the data sheet). If the RF signal is simultaneously fed to two coupled ports (i.e. if Gen is switched on so that at least one signal source is permanent), the port frequencies must be the same. For normal measurements (Gen switched off), this restriction does not apply because there is only one source port per partial measurement.
The frequency formula for a permanent signal source is also used for the second (coupled) test port.
Frequency Result displays the current frequency range (for frequency sweeps) or CW frequency (for power, time and CW Mode sweeps); see stimulus parameters.
Power opens an input box to define a port-specific source power range (for power sweeps) or fixed power (for frequency and CW sweeps). The result (not taking into account a possible Slope) is indicated in the Power Result column. In the default configuration the stimulus parameters (sweep range, internal source Power) are used.
Power Result displays the current power range (for power sweeps) or fixed internal source power (for frequency, time and CW Mode sweeps); see stimulus parameters.
PCor Off enables or disables a source power calibration for an individual port. This function is available only for ports where a source power calibration is available. It is identical with Source Power Correction Off in the Source Power Cal menu.
Slope defines a linear factor to modify the port-specific source power as a function of the stimulus frequency. The value can be set for frequency sweeps only.
Impact of the Slope
The channel power pb is defined by the following sweep settings:
For a power sweep, the channel power is equal to the stimulus range.
For a frequency or CW sweep, the channel power is equal to the fixed internal source Power.
The slope modifies the channel power pb so that the following port power ps (source power) is obtained:
ps = pb + <Slope> * D f
In the formula above, Df denotes the difference between the current source port frequency and the start of the stimulus frequency range. The Slope parameter is not available unless a frequency sweep is active.
SOURce<Ch>:POWer<Pt>:STATe ON | OFF SOURce<Ch>:POWer<Pt>:PERManent[:STATe] ON | OFF [SENSe<Ch>:]FREQuency:STARt? [SENSe<Ch>:]FREQuency:STOP? [SENSe<Ch>:]SWEep:CW|FIXed? SOURce<Ch>:POWer<Pt>[:LEVel][:IMMediate]:OFFSet SOURce<Ch>:POWer[:LEVel][:IMMediate][:AMPlitude]? SOURce<Ch>:POWer<Pt>:CORRection[:STATe] SOURce<Ch>:POWer<Pt>[:LEVel][:IMMediate]:SLOPe
Shows and/or defines the receiver settings for each physical port of the analyzer and each external power meter. No receiver settings are provided for external generators.
Some receiver settings can be defined independently for the reference channel a (the wave generated by the internal source and measured at the port) and the measurement channel b (the wave from the DUT) at each port.
LO a/b switch the two Local Oscillator amplifiers at the port on (box checked) or off.
Both LOs must be switched on to perform a system error correction.
Frequency opens an input box to define a converted receiver frequency range (for frequency sweeps) or CW frequency (for power, time and CW Mode sweeps). The converted receiver frequencies are valid for all ports. In the default configuration the stimulus parameters (sweep range, CW Frequency) are used. The result is indicated in the Frequency Result column.
PCor Off enables or disables a receiver power calibration for an individual port. This function is available only for ports where a receiver power calibration is available. It is identical with Receiver Power Correction Off in the Receiver Power Cal menu.
Atten defines port-specific attenuation factors for the received wave. The settings are analogous to the global Step Attenuator settings and replace them.
IF Gain b selects the IF gain in the receiver path.
Receiver path settings and AGC
The settings are valid for all ports:
Auto means that the analyzer adapts the IF gain to the RF input level (Automatic or Adaptive Gain Control, AGC). The A/D converter is always operated at optimum input level.
The following settings accelerate the measurement:
Low Dist(ortion) corresponds to a small IF gain(i.e. a lower internal A/D converter input level). This setting allows for a high RF overdrive reserve and is appropriate for high RF input levels.
Low Noise corresponds to a large IF gain(i.e. a higher internal A/D converter input level). This settingincreases the dynamic range and is appropriate for low RF input levels.
The Low Dist or Low Noise settings are appropriate whenever the characteristics of the input path must be constant, e.g. because:
Interfering signal contributions originating from the receiver (noise, nonlinear contributions) must not change during the measurement.
A large interfering signal in the vicinity of the measured signal must not overdrive the receiver.
[SENSe<Ch>:]LOMeasure [SENSe<Ch>:]LOReference [SENSe<Ch>:]FREQuency:STARt? [SENSe<Ch>:]FREQuency:STOP? [SENSe<Ch>:]SWEep:CW|FIXed? [SENSe<Ch>:]CORRection:POWer[:STATe] [SENSe<Ch>:]POWer:ATTenuation [SENSe<Ch>:]POWer:IFGain:MEASure
In the Source and Receiver sections of the Port Configuration table, it is possible to convert the source and receiver frequency ranges (for frequency sweeps) or CW frequencies (for power, time and CW Mode sweeps) in order to perform measurements on frequency-converting DUTs. The source frequency is port-specific whereas the receiver frequency must be the same at all ports.
Source frequencies are coupled if several sources share a common synthesizer. Refer to the synthesizer mapping information in the Hardware Info overview to find out which of the ports are coupled.
The port frequencies are calculated as a multiple of the stimulus frequency fb plus an offset. The coefficients of the linear transformation between fb and the port frequencies are entered in dialogs of the following type:
Relation between channel frequency and port frequencies
The stimulus frequency fb is defined by the following sweep settings:
For a frequency sweep or segmented frequency sweep, the channel frequency is equal to the stimulus range.
For a power, time or CW Mode sweep, the channel frequency is equal to the fixed CW Frequency.
This linear frequency conversion formula has been modeled according to the needs of a typical frequency-converting measurement where mixer products and harmonics occur (see also the special Mixer Modeand Harmonic Distortionmeasurements). The port frequencies f (source frequency fsor receiver frequency for the reference channel and the measurement channel fra/frb) are related to the stimulus frequency as follows:
k and m must be integer numbers, l and n nonzero positive integers. c must a multiple of 1 Hz. Moreover the total port frequency is rounded to an integer Hz-value.
SOURce<Ch>:FREQuency<Pt>:CONVersion:ARBitrary:IFRequency [SENSe<Ch>:]FREQuency:CONVersion:ARBitrary
In the Source section of the Port Configuration table, it is possible to define a port-specific source power range (for power sweeps) or fixed power (for frequency and CW sweeps).
The port power is first set to either the channel power pb plus an offset or to a constant value. The coefficients of the linear transformation equation between pb and the port powers are entered in a dialog.
If a frequency sweep is active, then it is possible to add a frequency dependent offset to the source power (Slope setting).
In addition to the port-specific source power the Port <n> Source Power dialog shows the Cal Power Offset. This parameter is relevant for source power calibrations with external amplifiers or attenuators and can be set via Channel – Calibration – Start Power Cal – Source Power Cal – Modify Settings – Modify Cal Power.
Relation between channel power and port powers
The port power ps (source power) is related to the channel power pb as follows:
In the formulas above, Df denotes the difference between the current source port frequency and the start of the stimulus frequency range, c is the offset value entered in the Port <nr> Source Power dialog. The Slope parameter is set in the Sourcesection of the Port Configuration table; it is not available unless a frequency sweep is active.
SOURce<Ch>:POWer[:LEVel][:IMMediate]:OFFSet <numeric_value>, ONLY | CPAD
Opens a dialog to customize the Port Configuration table and display or hide columns.
(Un)checking Logical Port, Source or Receiver displays (removes) the corresponding sections in (from) the Port Configuration table.
(Un)checking one of the second-level boxes displays (removes) the corresponding column in (from) the Port Configuration table.
The physical port number is always displayed. The logical port information is displayed only if a balanced port configuration is defined.
No command, display configuration only.