The following features, used with the PNA-X models and the N5264B, were designed specifically for Antenna applications.
The following Fast Sweep features allow you to very quickly measure and download data to a remote computer.
Fast CW, Fast Groups, and Fast CW Segments all work ONLY with the FIFO Data Buffer.
These features can be used ONLY with SCPI or COM commands. COM is faster than SCPI when using DataInCompactForm. Otherwise, SCPI is faster than COM.
The FIFO (First-IN, First-OUT) data buffer is a circular buffer that allows very fast Read-Write access.
5 GB FIFO buffer file on the E:\ drive. If the "not enough disk space" error message is displayed, clear all unnecessary files on the E:\ drive.
You can write to, and simultaneously read from, the FIFO buffer.
A maximum of 1 million data points can be read for each query.
REAL / IMAGINARY pairs is the ONLY supported format for the FIFO buffer.
A preset or instrument state recall will turn off the FIFO buffer collection.
When more than one measurement is present, data from each measurement is stored in the FIFO buffer in the following order. These measurements are separated into lines for easier reading.
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.
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.
FIFO is ON
A single channel is being measured. Other channels can be in Hold.
All measurements are acquired in a single sweep.
The channel must be in CW mode (start frequency = stop frequency or sweep type = CW Time).
IMPORTANT - Fast CW and IF Bandwidth setting
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Notes:
Fast CW sets the number of data points, overwriting the standard channel setting.
400,000 points/second applies to 600 KHz at a CW frequency with no point triggering. For narrower bandwidths the speed is slower.
Frequency switching time will reduce the speed. The frequency switching can be anywhere from 50 uS to 1 mS depending on the frequencies. The CW segment itself can go at 400,000 points per second.
All 5 receivers can do 400,000 point/second at the same time. So the data comes out at 5 times that rate, i.e. 2 Mp/s.
When exiting Fast CW, the FIFO data buffer is cleared.
External measurement trigger signals are allowed only on Meas Trigger.
The Aux 1 and Aux 2 triggers cannot be used per point in FastCW mode.
Aux 1 and Aux 2 triggers can still be used for external source hardware triggering, but the external sources must be in CW mode.
An error message appears if triggering is sent to the VNA faster than it can respond.
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:
FIFO is ON
A single channel is being measured. Other channels can be in Hold.
All measurements are acquired in a single sweep.
Group trigger is enabled with count > 1.
Notes:
Fast CW can NOT be used with Fast Groups.
Fast Groups and Fast CW Segments were designed to be used together, but not required.
The FIFO Tester example program demonstrates this feature.
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:
FIFO is ON
Start and stop frequency of a segment is identical.
External measurement trigger signals are allowed only on Meas Trigger.
The Aux 1 and Aux 2 triggers cannot be used per point in Fast CW Segment.
Aux 1 and Aux 2 triggers can be used for external source hardware triggering.
Notes:
Fast CW can NOT be used with Fast CW Segments.
The sweep can include non-CW segments, but these are not acquired in Fast mode.
Fast Groups and Fast CW Segments were designed to be used together, but not required.
The FIFO Tester example program demonstrates this feature.
In Fast CW Segments, when data is not being acquired in real-time, the following message appears: Caution: Sweep time jitter. Try reducing the number of segments. To avoid this error, reduce the number of segments in the channel.
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.
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.
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.