This topic applies to the following instrument models: M9384B VXG and M9484C VXG.
Optimize Dynamic Range with OBW
This area comprises immediate, single-action controls common to most instruments.
Click this button to send the parameters to the connected instrument.
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SCPI Command |
[:SOURce]:RADio:<app>:PLAYback:VXG:UPDate:TO |
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SCPI Example |
RAD:NR5G:PLAY:VXG:UPD:TO |
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State Saved |
No |
Click this button to retrieve the parameters from the connected instrument.
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SCPI Command |
[:SOURce]:RADio:<app>:PLAYback:VXG:UPDate:FROM |
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SCPI Example |
RAD:NR5G:PLAY:VXG:UPD:FROM |
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State Saved |
No |
Click this button to set the signal generator to a factory-defined or user-defined state.
Refer to the signal generator's user's guide for information on setting a user-defined state.
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SCPI Command |
[:SOURce]:RADio:<app>:PLAYback:VXG:PRESet |
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SCPI Example |
RAD:NR5G:PLAY:VXG:PRES |
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State Saved |
No |
Set ALC to Off to activate this button.
Click the Power Search button to execute a manual power search calibration. This is an internal calibration routine that improves output power accuracy when the ALC is turned off. A power search is recommended for pulse-modulated signals with pulse-widths less than two microseconds.
Download a waveform to set the correct parameters for the target instrument.
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SCPI Command |
[:SOURce]:RADio:<app>:PLAYback:VXG:ALC:SEARch |
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SCPI Example |
RAD:NR5G:PLAY:VXG:ALC:SEAR |
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State Saved |
Yes |
Establishes a remote connection to the selected instrument.
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SCPI Command |
[:SOURce]:RADio:<app>:PLAYback:VXG:CONNect |
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SCPI Example |
RAD:NR5G:PLAY:VXG:CONN |
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State Saved |
No |
When the Hardware node is selected in the left pane, common hardware configuration parameters appear here.
Name |
The product name/model of the instrument. The name appears as the instrument node in the left pane of the Hardware screen.
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Number of Hardware Channels |
Enter the number of channels for a specific instrument model. For multiple channels, the first instrument listed will become the primary. The others will be secondary.
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Connection State |
Reports whether or not you have remote connection to the instrument.
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Selected |
Reports whether or not you have selected a particular instrument for remote control.
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Address |
Enter the instrument’s IP address or hostname. This parameter is coupled with Address under instrument configuration. See that description for SCPI command. |
When an instrument model is selected in the left pane, configuration parameters pertaining to that instrument appear here.
Frequency |
Enter a value to set the signal generator’s output frequency. Use abbreviations for faster entry (example: 1g = 1.000000000000 GHz). For frequency range values, see the instrument's data sheet.
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Amplitude |
Enter a value to set the signal generator’s output amplitude in dBm.
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RF Output |
Click the checkbox to enable (checkmarked) or disable the RF Output.
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RF Flatness Correction |
Click the checkbox to enable (checkmarked) or disable the RF flatness correction.
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I/Q Adjustments |
Click the checkbox to enable (checkmarked) or disable the I/Q Adjustments. On – The values entered for I Offset, Q Offset, and so on are applied to the I and Q signals. Off – I/Q adjustment values are not applied to the I and Q signals.
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I Offset |
Enter a DC offset value (in percent) to apply to the I signal before the I/Q modulator. Use this offset to remove imperfections in the in-phase signal or to introduce calibrated impairments. When using this setting to minimize the LO feed-through signal, optimum performance is achieved when the adjustment is made after any other I/Q path adjustments. If other adjustments are made after minimization is performed, the LO feed-through signal may increase. Set I/Q Adjustments to On to enable this parameter.
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Q Offset |
Enter a DC offset value (in percent) to apply to the Q signal before the I/Q modulator. Use this offset to remove imperfections in the in-phase signal or to introduce calibrated impairments. When using this setting to minimize the LO feed-through signal, optimum performance is achieved when the adjustment is made after any other I/Q path adjustments. If other adjustments are made after minimization is performed, the LO feed-through signal may increase. Set I/Q Adjustments to On to enable this parameter.
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I/Q Gain Balance |
Enter a gain ratio (in dB), by which I gain exceeds Q gain. For example, if you enter a value of 1 dB, the I signal will have 1 dB more amplitude than the Q signal. Use the gain balance to remove imperfections in I and Q or introduce calibrated impairments. Set I/Q Adjustments to On to enable this parameter.
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Quadrature Angle Adjustment |
Enter a value (in degrees) to adjust the Q phase angle. When the quadrature skew is zero, the phase angle between the I and Q vectors is 90 degrees. Positive skew increases the angle from 90 degrees; negative skew decreases the angle from 90 degrees. Set I/Q Adjustments to On to enable this parameter.
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I/Q Skew |
Sets the time delay (in seconds) between I and Q. A positive value delays the I signal relative to the Q signal, and a negative value delays the Q signal relative to the I signal. Enter a value to change the absolute phase of both I and Q with respect to triggers and markers. A positive value delays I and Q. This value affects both the external I/Q out signals and the baseband signal modulated on the RF output. This adjustment cannot be used with constant envelope modulation and does not affect external I/Q inputs. Set I/Q Adjustments to On to enable this parameter.
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I/Q Delay |
Enter a value (in seconds) to set the I/Q delay with respect to triggers and markers. Set I/Q Adjustments to On to enable this feature.
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Optimize Dynamic Range with OBW |
Filters the system RF flatness correction coefficients over the instantaneous bandwidth indicated in the waveform header (or in the “Occupied Bandwidth” settings area under the Signal block when Waveform File is the Vector Modulation Signal Mode). This has the potential to improve EVM performance by not having to correct for flatness errors outside the requested bandwidth.
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ALC AUTO |
Click the checkbox to enable (checkmarked) or disable ALC On and ALC Bandwidth couplings. For IQ modulation, ALC Auto and Power Search Auto should be On.
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ALC |
Click the checkbox to enable (checkmarked) or disable the automatic level control (ALC). On – The ALC circuit constantly monitors and controls the output power level. Off – No automatic leveling occurs.
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ALC Bandwidth |
Sets the detector feedback loop bandwidth depending on the modulation type running on the system to reach the requested absolute output power requested. Very narrow loop bandwidths (Very Slow) causes the leveling loop to pass rapidly changing amplitude levels, but still corrects for slow amplitude drift due to temperature variations or other effects over longer durations of time. Slow or Medium increases the loop bandwidth to partially correct/level for rapidly changing amplitude fluctuations. Fast increases the loop bandwidth provide rapid correction of or rapidly changing amplitude fluctuations. For IQ modulation the ALC & Power Search should always be set to Auto. Very Slow – use for CW or modulation with low rate amplitude variation Slow or Medium – use for CW or modulation without amplitude variation Fast – use for CW, FM and pulse operation
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Power Search Auto |
Toggles Power Search Mode between On or Off. When enabled, power search calibration routine is executed whenever an instrument setting is modified. This includes changes to frequency, amplitude and modulation. For IQ modulation, ALC Auto and Power Search Auto should be On. For M9384B/M9484C VXG, this parameter is grayed out and set to Very Slow when ALC Auto is On.
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Runtime Scaling |
Runtime Scaling adjusts the scaling of the I and Q data. Reducing the runtime scaling prevents the over ranges from happening. Runtime scaling is also used to scale signals relative to each other.
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Baseband Power |
Sets the baseband power in dB.
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Sample Clock |
The sample clock frequency of the signal generator is automatically calculated by the program. The range depends on the connected instrument.
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Pulse/RF Blank |
Use the drop-down menu to select an RF blanking function. None – disables RF blanking. Marker 1 through Marker 4 – selects a marker to activate RF blanking. Pulse/RF Blanking turns off the RF output signal during specific conditions determined by the marker. RF blanking incorporates ALC hold, so you do not need to select ALC hold when using RF blanking. Do not blank longer than 100 ms to avoid exceeding the ALC hold limit.
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ALC Hold |
Use the drop-down menu to select a marker for ALC hold. Use ALC hold when you have a waveform signal that has idle periods, or when the increased dynamic range with RF blanking is not desired. None – disables ALC hold. Marker 1 through Marker 4 – assigns a marker for the ALC hold function. When the specified marker polarity is positive and the marker signal is low (no marker points), ALC hold is on, and the output power level does not respond to changes to the signal amplitude. When the marker signal is high, the ALC samples the waveform points and averages the waveform amplitudes to set the ALC circuitry for the next ALC hold period. RF blanking incorporates ALC hold, so there is no need to select ALC hold when using RF blanking. Limit ALC Hold to no more than 100 ms, as the ALC Level may degrade. The hold selection remains until you reconfigure it, preset the signal generator, or cycle the signal generator power. Incorrect ALC settings can cause a sudden unleveled condition to occur. An unleveled RF output can damage a DUT or connected instrument. Ensure that you set markers such that the ALC obtains a sample that accounts for the high power levels within the signal.
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Playback Synchronization |
Click the checkbox to enable (checkmarked) or disable playback synchronization. Only applied when Trigger Source is set to External and Trigger Type is set to Continuous.
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Trigger Mode |
Use the drop-down menu to select the triggering mode. Continuous – selects the continuous triggering mode, which enables the signal generator to repeat the modulating signal indefinitely until you turn off the modulation format, change triggers, or select another waveform. Single – sets up a waveform to play once after receiving a trigger.
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Continuous Mode |
Use the drop-down menu to select the continuous mode and one of the following trigger responses. Free Run − immediately triggers when you turn the format on. Trigger & Run − waits for and starts on the first trigger; ignores subsequent triggers. Reset & Run − waits for and starts on the first trigger; resets and plays on a subsequent trigger.
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Single Mode |
Double-click or use the drop-down menu to select the single mode and one of the following trigger responses. No Retrigger (OFF) – the waveform segment ignores triggers during playback Buffered Trigger (ON) – causes a waveform to accept a trigger during playback and to restart after the current play finishes. Restart on Trigger (IMMediate) – causes a waveform to accept a trigger during playback and to restart immediately after receiving a trigger.
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Trigger Source |
Adjusts the trigger source applied to the PATT TRIG IN or AUX I/O connectors. External (EXT) – enables you to trigger a waveform with an externally supplied trigger signal. Bus (BUS) – enables you to trigger a waveform by sending a command through the GPIB, LAN, or AUXILIARY IO (RS-232) input connector. Trigger Key (KEY) – selects the front panel hardkey as the trigger source. After making this selection, press the Trigger hardkey to trigger a waveform. Immediate (IMM) − enables immediate triggering of the waveform playing.
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External Termination |
Sets the external trigger termination.
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External Polarity |
Sets the polarity of the external trigger. This parameter is active only if you select external (Ext) as the trigger source. Positive – the signal generator triggers an event when it detects a rising edge on the PAT TRIG IN signal. Negative – the signal generator triggers an event when it detects a falling edge on the PAT TRIG IN signal.
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External Delay Time |
Sets a delay time (in seconds) between when an external trigger is received and when it is applied to the waveform.
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External Level |
Sets the external trigger level in volts.
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AWGN On |
Click the checkbox to enable (checkmarked) or disable adding real-time, non-repeating additive white Gaussian noise (AWGN) to the carrier being modulated by the waveform being played.
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Power Control Mode |
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Carrier to Noise Ratio Format |
Set the carrier power to noise power (C/N) ratio format.
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Carrier to Noise Ratio | Enter a value (in dB) to set the noise power as a ratio of carrier power to noise power (C/N). Carrier power equals the total modulated signal power before noise is added. When you add noise, the power output from the signal generator does not change; it is the sum of carrier power and the added noise power.
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Eb/No |
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Total Noise Power |
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Carrier Power |
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Channel Noise Power |
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Flat Noise Power |
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Carrier Bandwidth | Specifies the bandwidth (in Hz) over which the noise power is integrated for calculating the carrier to noise ratio (the bandwidth of the target carrier).
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Flat Noise Bandwidth | Sets the flat noise bandwidth (in Hz), which is typically set wider than the carrier bandwidth.
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Carrier Bit Rate |
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Output Mux |
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