Input Extensions (M9415A/M9416A)

Table of M9415A/M9416A Hardware Configuration Parameters

Parameter	Possible Values	Default
Misc
Adc Dither	Auto, Off, On, High	Auto
Capture Bit Packing	Auto, 32 Bits per Point, 64 Bits per Point	Auto
Ext Reference Lock Bandwidth	15 Hz	15 Hz
External Trigger Location	Trigger 1 In, Trigger 2 In	Trigger 1 In
IF Path	String containing the name of the IF path	Hardware dependent
IF Path Auto	Off, On	On
Instrument User Corrections	Off, On	Off
LO Dither	Off	Off
Microwave Path Control	Standard	Standard
Mixer Mode	Normal	Normal
Phase Noise Optimization	Best Close In, Fast Tuning	Best Close In
RF Input Port	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). Input, RFIO HD	RF Input
Signal Path (Deprecated)	Auto, Wideband (1.2 GHz Gigahertz: A frequency measurement which equals one billion hertz.)	Auto
Wideband IF Output	Off	Off
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
Range
Preamplifier / LNA	Off, LNA Low Noise Amplifier	Off

Misc

Adc Dither

Adc Dither selects either to improve the distortion or signal-to-noise ratio measurement performance. Selecting Adc Dither will improve the measurement distortion performance but at the expense of decreased signal to noise ratio performance. Adc Dither is implemented by applying an out of band random dither signal to the input of the ADC Analog-to-Digital Converter.

Auto (Default) - This is the same as the Off mode.
Off - Dither is turned off.
On - Dither is applied at 6% of full scale.
High - Dither is applied at 18% of full scale. The High setting is only valid for some analyzer models. In other analyzers the High mode is the same as the On mode.

Capture Bit Packing

Capture Bit Packing 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 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.

Ext Reference Lock Bandwidth

Ext Reference Lock Bandwidth is the external reference signal bandwidth. Ext Reference Lock Bandwidth is fixed at 15 Hz.

External Trigger Location

External Trigger Location values are as follows:

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.

The Trig 1 and Trig 1 connectors are configurable to be used as either trigger out or trigger in on the M9415A. Therefore, the choice of this parameter should be done so as to not conflict with the Input > Trigger >Trigger Out parameter. If there is a conflict, Trigger Out will be disabled and this parameter will take precedence.

IF Path

The IF Path parameter is used to specify which IF signal path to use. When IF Path Auto is On, the value is set by VSA software. The parameter value is a string containing the name of the IF path. This name is formatted as three fields separated by underscore: bandwidth_pathType_model.

Bandwidth - an integer value in Hz. This is a required field.
PathType - StandardN or AlternateN, where N is an integer greater than or equal to 1. Path type is model specific. Alternate paths are available depending on instrument model and options. This field is optional for the default pathType, which is Standard1.
Model- the instrument model. When setting IF Path, this field is optional for the default value, which is the instrument model of the current hardware configuration.

Only bandwidth is returned for a standard IF path. Bandwidth and path type are returned for an alternate path. In most cases the value of IF Path will be only the bandwidth (e.g., “1000000000” for a standard 1 GHz IF path).

IF Path Auto

The IF Path Auto parameter is used to specify how the measurement analog IF path is selected.

On (Default): The VSA automatically selects the best IF path for the specified measurement span, trigger type and segmented capture.

Off: Path is set by IF Path parameter.

Instrument User Corrections

Instrument User Corrections specifies whether the input channel corrections defined in the M9415A VXT are applied to captured data.

Off (Default) - Disables instrument user corrections.
On - Enables instrument user corrections.

LO Dither

LO Dither is fixed to Off.

Microwave Path Control

Microwave Path Control is fixed to Standard.

Mixer Mode

Mixer Mode is fixed to Normal.

Phase Noise Optimization

Phase Noise Optimization values 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

RF Input values are as follows:

RF Input (Default) - RF Input port.
RFIO HD - RF Input/Output port. It provides half duplex IO capability depending on the configuration.

Signal Path (Deprecated)

This property is deprecated. Use IF Path and IF Path Auto to set the signal path.

Signal Path values are as follows:

Signal Path is used to optimize the measurement analog signal path for the maximum available span.

Auto (Default) - Automatically selects the best signal path for the maximum available span.
Wideband (1.2 GHz) - Selects the wideband signal path.

Wideband IF Output

Wideband IF Output is fixed to Off.

Parameters Influenced by the Measurement Type

IF Offset Freq Auto

Select whether IF Offset should be automatically controlled.

The actual IF Offset Freq used internally will not be updated in the IF Offset Manual Freq property when Auto is On.

When IF Offset Freq Auto is On, no indication is given in the VSA software about whether actual spur dodging is occurring or not.

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.

Range

Preamplifier / LNA

Select whether to turn on a preamplifier in the signal path.

Off (Default) - Preamplifier is off.
LNA - This is a low noise amplifier (or preamplifier) that is usable at all frequency ranges and all microwave paths.

Other selections may be visible. Only the selections described in this topic are valid. If a selection is chosen that is not valid, the default setting will be selected instead.

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