1-Tone Measurement Panel: Sweep Settings

Acquisition mode:

• Power per Frequency: for each frequency acquisition, a ramp of RF power will be sent to the DUT.
  
  
  
  
• Frequency per Power: for each power, the acquisition is done for all frequencies.
  
  
  
  
• Smart measurement is an advanced power per frequency mode. The ramp of power is not linear but adaptive to achieve a targeted value.
  
  
  
  
• Fast CW is a sweeping method that can be used to improve the measurement speed. Contrary to the classical power sweep where IQSTAR is sweeping the VNA power, the VNA is here asked to sweep the power for a fixed frequency, asking the instruments to bufferize the measured values, and resulting in a great speed improvement.
  DANGER: When using this type of sweep, the measurement stop conditions will not be verified because of the VNA sweeping entire power sweeps. The DUT will not be under IQSTAR protection and measurement can lead to damages. It is important to know the limits to not exceed in this case.
  
  
  
  
  

  For more informations about how to setup a Fast CW bench, see Getting Started : "Fast CW measurements".

Fequency Sweep Settings

• Frequency sweep (Hz): the calibration frequency list will be set by default. Click on icon to open the 'Frequency editor' and modify the frequency list
  Note: 'Frequency editor' is a tool used to define frequency sweeps or frequency segments. Click on 'Clear' or 'Inject into list' to add or remove frequencies. It is possible to select the frequencies available in the selected calibration file by clicking on 'Select frequencies from calibration'. It's also possible to save or load a frequency list (*.freq files) using icons.

  
  

  

  
  
• Harmonics: set the number of harmonics to measure (1 to 4)
• Allow frequency interpolation: if the list of RF stimulus frequencies is different from the calibrated one, IQSTAR will interpolate the errors terms

Power Sweep Settings:

If 'Power per Frequency' or 'Frequency per Power' is selected:

• Type: the power sweep can be of different types:
  • Raw power: the power is not optimized, IQSTAR only send the command to the RF source
    Note: If Driver Amplifier is defined in the schematic, the power defined will take into account the driver amplifiers offset set in the schematic.
  • Raw power (calibrated): available if the Raw Power Calibration has been performed, there is no optimization but the power is increased by an offset from the Raw Power Calibration coefficients
  • Available input power: the available power is optimized at the input of the DUT
  • Delivered input power: the delivered power is optimized at the input of the DUT
  • Output power: the output power is optimized at the output of the DUT
• Ignore level setting errors until first success: if there is a power optimization, IQSTAR moves to next power level if the optimisation does not reach the previous target

• Target settings
  • Type: select the target to reach (it could be a gain compression or a power level)
  • Point count: (available only in linear gain compression mode) set the number of point to compute the average level of the linear power
  • Level: set the target level to reach

• Sweep settings
  • Min/Max power: set the power range authorized for the optimization
  • Maximum step: set the maximum power step achievable between two points
    Note: When the gain compression is selected as target, the algorithm is based on the gain slope. First step will be equal to the maximum step, then this step will decrease in function of the gain slope value.
  • Perform IV measurement only on last point: check this box in order to speed up the measurement by measuring the IV performance only at the target level and not for each power level
    Note: In this case, no post measurement interpolation will be possible.
• Fine mode

  Basic mode using coarse step can lead to an overdrive of the DUT.

  
  
  
  
  

  With the fine mode, more iterations are used as the gain becomes closer to the target compression point, which minimizes excess drive power.

  
  

  

  
  
  • Maximum fine step: define the maximum step size achievable when the threshold of fine mode is reached
  • Compression threshold: set the value of gain compression to trigger fine mode

VSWR

• Enable preview (blue points):set active the preview in the smith chart. Red points are already added, blue are the current ones being set up.

• Max VSWR: pattern max VSWR
• VSWR res.: pattern VSWR resolution
• Angular res.: pattern VSWR angular resolution
• Filled: if check, the pattern is filled with points distance of VSWR resolution value. If unchecked only the circumference points will be active.
• Central point: activates the 50 Ohms point if checked.

Important: Once the pattern is created, the ADD button needs to be pressed to turn them into red and use them during the measurements. The CLEAR button can be used to empty the pattern.

Note: If some frequencies defined in Fequency Sweep Settings are not include in the tuner pre-characterization file (*.tun), IQSTAR will use the lowest tuner pre-characterized frequency compare to the requested frequency in order to control the tuner. This will lead to a VSWR phase contrrolled shift compared to the VSWR phase targetted. In this case, following warning will appear at the beginning of measurement.

Fast CW settings (Available with Fast CW only):

When fast power sweeps are needed and the device is know well enough (Stop conditions ignored in this mode), the Fast CW mode can be used.

If the used IV multimeters are compatible with burst measurements, instrument measurement ranges will need to be selected in this table. If some instruments do not have this burst capability, please refer to DC Measurement. Triggers also needs to be defined and are positive edge by default.

If an instrument has no burst capability, the following message should appear:

Minimum setting time: sets a delay between the VNA power sweep points. Can be used to achieve a DUT steady state before measuring a value.

Quiescent current stabilization (Available with Power per Frequency, Smart and Fast measurements):

• Start measurement for: set the level (in % of initial value) of quiescent current to be reached before a new sweep can start
• Current access: choose the current access to apply the condition
  Note: It is also possible to create an expression in order to define a custom current (e.g. sum of two currents).

  
  

  

  
  
• Stabilized value count: set the number of consecutive measurements that must be within the tolerance
  When 'Quiescent current stabilisation' is enabled. An additional window will pop up during measurements to display the quiescent current value, the reference current level and the current tolerance. This curve can then be saved in a file if needed.