Setting Up a Transient measurement

 

The transient measurement has two measurement modes: Wide and Narrow. Wide band can observer the frequency transition in wider window.

Narrow band can observe the transient measurement of  frequency, power and phase vs. time in narrower window.

 

Configure Transient Sweep settings

Using Hardkey/SoftTab/Softkey

Using a mouse

  1. Press Meas > Transient >  Transient Setup....

  1. Click Stimulus

  2. Select Transient Setup...

 

 

Transient setup: Sweep tab help

Sweep Type

Wide-Narrow- Wideband (WB) and one narrow band (NB1) measurements

Narrow-Narow - two narrow band measurements, Narrow band 1 (NB1) and Narrow band 2 (NB2). Both bands are identical.

 

Time Coupling - All traces for both measurement share the same time settings.

NOP - Shows the number of Point in the transient sweep. NOP is automatically set and cannot be changed.

Wide

  • Frequency Range - Specify the frequency range of wide band.

  • Max Frequency - Input the maximum frequency. This input is required when the frequency band is set at Max Freq. > 8 GHz.

  • Min Frequency- Shows the minimum frequency according to the specified maximum frequency.  (Minimum frequency = Maximum Frequency - 7 GHz)

  • VBW - Default is Auto (Auto Check Box is enabled). A larger VBW can measure faster transient but frequency measurement fluctuation will be bigger

  • Time Span - Specify the time span of horizontal axis.

Frequency Range

Minimum Time Span

1 MHz – 40 MHz

200 μs

40 MHz – 160 MHz

10 μs

80 MHz – 320 MHz

10 μs

160 MHz – 640 MHz

10 μs

320 MHz – 1.28 GHz

10 μs

640 MHz – 2.56 GHz

10 μs

1.28 GHz – 5.12 GHz

10 μs

2.56 GHz – 8 GHz

10 μs

256 MHz – 8 GHz

200 μs

8 GHz - 54 GHz

10 μs

  • Time offset - Specify the offset time at the reference point

  • Reference - Specify the reference location of the horizontal axis. Choose from Right, Center or Left.

Narrow1/Narrow2

  • Center Frequency - The center frequency of narrow band 1/2. It is the value at reference point of vertical axis of Narrow band window.

  • Frequency Span - The frequency span of narrow band 1/2. The minimum time span and minimum center frequency are limited by this as follows. The power measurement in narrow band cannot be selected when the frequency span is 80 MHz and above.

    Frequency Span

    Minimum Time Span

    Minimum Center Frequency

    3.125 kHz

    100 ms

    900 kHz

    25 kHz

    10 ms

    900 kHz

    312.5 kHz

    1 ms

    900 kHz

    2.5 MHz

    100 μs

    5 MHz

    10 MHz

    50 μs

    100 MHz

    30 MHz

    10 μs

    200 MHz

    80 MHz

    10 μs

    200 MHz

    160 MHz

    10 μs

    400 MHz

    320 MHz

    10 μs

    800 MHz

  • VBW - Default is Auto (Auto Check Box is enabled). A larger VBW can measure faster transient but frequency measurement fluctuation will be bigger

  • Time Span - The time span of horizontal axis.

  • Time offset - The offset time at the reference point

  • Reference - Select the reference location of the horizontal axis. Choose from Right, Center or Left.

Note: Displayed area (time and frequency) needs to be set to keep frequency transient within NB1 Center Freq +- NB1 Freq Span / 2. Otherwise, a user will see an invalid trace. The same applies to Narrow band 2. Displayed area needs to be set to keep frequency transient within NB2 Center Freq +- NB2 Freq Span / 2.

NOP and Linear Interpolation

Transient sweep can measure two different bands’ parameters simultaneously and each band’s NOP will be set automatically depending on parameter settings (band span/range, VBW, timespan). To display these different, NOP parameters on the same display window, Linear interpolation will be performed for some Transient parameters. Here is the rule of NOP/interpolation.

Band 1/2 definition

Example

Transient setup: RF Path tab help

RF 1/2 Input - Select RF input port for 2 port model.

Maximum Input Level - Specify the Maximum input level.

[...] - Open the following Receiver Attenuator Setting dialog box.

 

Enable Attenuator Setting - Uncheck: Appropriate attenuator value is set automatically according to the specified Maximum Input Level. / Check: Set the specified attenuator value.

Attenuator - This attenuator values is set when Enable Attenuator Setting is checked.

 

Transient setup: Trigger tab help

Enable Video Trigger - Enable the Video Trigger function.

Select Trigger - Select the trigger source from Wide, Narrow1 or Narrow2.

Trigger Type - Select Frequency or Power. Power is available in Narrow band only.

Target - Target value which make a video trigger

Hysteresis  - Hysteresis triggers eliminate incorrect triggers caused by noisy signals. For example, if your signal contains several rising edges of different amplitudes, you can use hysteresis triggering to trigger on one of the edges.

Edge - Select the trigger edge from positive or negative.

Min Input Level - Minimum power input level for the video trigger. The relative value (dB) from the maximum input level should be specified. The trigger is disabled when the narrow band power measurement level is below the specified value. This does not work when the frequency span is 80 MHz and above because the power measurement is not available in the spans.

Holdoff - An trigger insensitive period after the previous trigger. The trigger is disabled during this period, even if the trigger conditions are met.

Note: To detect the trigger points the Video Trigger uses the raw data before VBW is applied. The VBW changes the wave shape. Hence, the triggered points may be different from the points of displayed trace.