Fast CW Mode (Opt S93118A/B) and other Antenna Features


The following features, used with the PNA-X models and the N5264B, were designed specifically for Antenna applications.


Fast CW Mode Features (Opt S93118A/B)

The following Fast Sweep features allow you to very quickly measure and download data to a remote computer.  

The FIFO Data Buffer

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

4-port models

R, A, B, C, D,

R/R, A/R, B/R, C/R, D/R,

R/A, A/A, B/A, C/A, D/A,

R/B, A/B, B/B, C/B, D/B,

R/C, A/C, B/C, C/C, D/C,

R/D, A/D, B/D, C/D, D/D

2-port models

R1, R2, A, B,

R1/R1, R2/R1, A/R1, B/R1

R1/R2, R2/R2, A/R2,B/R2

R1/A, R2/A, A/A, B/A

R1/B, R2/B, A/B, B/B

S-parameters are pre-defined, ratioed-receiver measurements. Learn more. S-parameters are placed in the FIFO in order based on their underlying receivers. For example, S21 is placed into the FIFO in the same manner as B/R1.

Fast CW

In Fast CW mode the VNA display is not updated. There is no background computation or other 'interference' from the VNA computer. Therefore, data is acquired real-time.

The following requirements must be met before sending the Fast CW command.

IMPORTANT - Fast CW and IF Bandwidth setting

  • IF Bandwidth of 10 kHz and lower - Data is transferred immediately to the FIFO after every acquisition.

  • IF Bandwidths greater than 10 kHz - Data is transferred to the FIFO in groups. A triggered acquisition is NOT placed into the FIFO buffer until either the total number of points is completed, or an intermediate group of points is finished. The number of points within a group differs for each IF Bandwidth setting.

Notes:

Fast Groups with FIFO Data Buffer

With this speed optimization feature, interaction with Windows or other VNA 'overhead' calls are suspended, allowing very fast and predictable measurement timing.  

Fast Groups is automatically enabled when the following requirements are met:

Notes:

Fast CW Segments with FIFO Buffer

In this optimization feature, each CW segment (where the start and stop frequency is identical) within a channel is measured at speeds as fast as the Fast CW mode sweep.

Fast CW Segments is automatically enabled when the following requirements are met:

Notes:

Other Antenna Features

Point Averaging

This feature is selected on the Average dialog.

When selected, each data point is measured the specified number of averages before stepping to the next data point. When point trigger is selected, only one trigger is required for each data point regardless of the number of averages.

Point Sweep

This feature is selected on the Sweep Setup dialog.

In Point Sweep mode, the VNA measures both the forward and reverse parameters at each frequency point before stepping to the next frequency. The display trace is updated as each data point is measured. Point sweep is the same as stepped sweep mode of the 8510 and 8530.  

Trace Triggering

This feature is selected under Trigger Mode on the Trigger dialog.

Available ONLY when Point Sweep is selected. Each trigger signal causes two identical measurements to be triggered separately - one trigger signal is required for each measurement. Other trigger mode settings cause two identical parameters to be measured simultaneously.

Trace triggering is NOT permitted when a channel is using a 2 port (or more) S-Parameter calibration.

See Also