Input Extensions (M9410A/M9411A)

Menu Path: Input > Extensions

Table of M9410A/M9411A Hardware Configuration Parameters

Parameter	Value	Default
Misc
Capture Bit Packing	Auto, 32 Bits per Point, 64 Bits per Point	Auto
External Trigger Location	Trigger 1 In, Trigger 2 In	Trigger 1 In
Phase Noise Optimization	Best Close In, Fast Tuning	Best Close In
RF Input Port	Half Duplex, RF Radio Frequency: A generic term for radio-based technologies, operating between the Low Frequency range (30k Hz) and the Extra High Frequency range (300 GHz). In	RF In
Parameters Influenced by the Measurement Type
IF Offset Freq Auto	Off, On	On
IF Offset Manual Freq (Avoid Spur)	±(MaxSignalPathBandwidth - Current Span)/2	0
Influence Criteria	Normal, Spectral Quality	Normal
Influence Criteria Auto	Off, On	On

Misc

Capture Bit Packing

The Capture Bit Packing parameter specifies the resolution of the recorded measurement data. The Capture Bit Packing setting affects the available maximum capture time.

• Auto (Default) - The VSA will use 32 bits/data point for measurement spans greater than 40 MHz Megahertz: A unit of frequency equal to one million hertz or cycles per second. and 64 bits/data point for measurement spans less than or equal to 40 MHz.
• 32 Bits per Point - The hardware will capture complex data at 32 bits per complex data point (16 bits for the real part and 16 bits for the imaginary part). The data is converted to a floating point data type before saving to the disc file.
• 64 Bits per Point - The hardware will capture complex data at 64 bits per complex data point (32 bits for the real part and 32 bits for the imaginary part). The data is converted to a floating point data type before saving to the disc file.

For measurement spans greater than 40 MHz, 32 bit packing is sufficient because at these bandwidths the input noise of the ADC Analog-to-Digital Converter will dominate the measurement results. However, for narrower spans the processing gain will drive down the noise floor so that the dominating factor will be the quantization noise introduced by 32 bit packing. In this case, 64 bit packing can be used to provide a lower noise floor for input signals.

However, when the dominating factor is the noise on the input signal or when a lower noise floor is not needed, bit packing can be switched to 32 bits/data point to enable longer recording times.

External Trigger Location

• Trigger 1 In (Default) - This selection maps to the Trig 1 connector on the VXT.
• Trigger 2 In - This selection maps to the Trig 2 connector on the VXT.

Phase Noise Optimization

The RF Input Port values that are user-changeable are as follows:

• Best Close In (Default) - For measurement analysis regions less than 25 kHz kiloHertz: A radio frequency measurement (one kilohertz = one thousand cycles per second). from the input signal.
• Fast Tuning - Provides faster settling but a higher phase noise level.

RF Input Port

The RF Input Port values that are user-changeable are as follows:

• RF In (Default) - RF Input port.
• Half Duplex - RF Input/Output port. It provides half duplex IO capability depending on the configuration.

Parameters Influenced by the Measurement Type

IF Offset Freq Auto

Select whether IF Offset should be automatically controlled.

• On (Default) - In 'Auto' mode, the Optimization Criteria will determine the auto behavior.

• Off - In 'Manual' mode, the IF Offset Manual Freq value will be used.

IF Offset Manual Freq (Avoid Spur)

Select an IF offset (in hertz) to use when IF Offset Freq Auto is set to Manual. This allows the user to set a specific offset for the IF in Hertz which will then be compensated for by a corresponding offset in the reverse direction after the digitizer so that the requested center frequency is still at the center. This can be useful for moving the position of spurs and images relative to the desired center frequency. See About IF Offset Freq and Spur Avoidance for more information.

The limits for this value are +/- ((max span - current span) / 2). The parameter priority is Center, Span, and then IF Offset Freq, so the IF Offset Freq will be coerced if needed as the span is changed. If the user changes IF Offset Freq while IF Offset Freq Auto is On, it will internally force IF Offset Freq Auto to Off. A positive value shifts the spur to the right in the spectrum display and a negative value shifts it to the left. The IF Offset Freq is coerced to 0 if the IF Path Auto property is set to On (even though it may internally choose to use a non-zero value). This parameter is for the manually entered value and does not reflect what the auto-chosen value might be when Auto is on.

Influence Criteria

Select the criteria for how to influence other parameters that are part of the 'Parameters Influenced by the Measurement Type' category. This influences what the IF Offset behavior will be when IF Offset Freq Auto is set to Auto.

• Normal (Default) - IF Offset is set to 0.
• Spectral Quality - Avoids spurs if the span is small enough to internally control the IF Offset to avoid spurs.

Influence Criteria Auto

Select whether the influence criteria is automatically determined based upon the current type of measurement.

• On (Default) - Power spectrum-based measurements will choose to use the 'Spectral Quality' criteria. Otherwise, the 'Normal' criteria will be used.
• Off - Manually select the Influence Criteria.

 

To change an M9410A/M9411A input extension, follow these steps:

1. Be sure that the M9410A/M9411A is selected as the Current Analyzer Configuration
2. Click Input > Extensions
3. Select an available input extension and make a selection from the drop-down menu.

Click Preset All to preset all input extension parameters across all logical instruments and channels.

See Also

About Keysight M9410A/M9411A