Input Extensions (E6680A/E6680E)

Table of E6680A/E6680E 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
Instrument User Corrections	Off, On	Off
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 E6680A/E6680E.
Trigger 2 In - This selection maps to the Trig 2 connector on the E6680A/E6680E.

The Trig 1 and Trig 1 connectors are configurable to be used as either trigger out or trigger in on the E6680A/E6680E. 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.

Instrument User Corrections

The Instrument User Corrections parameter specifies whether the input channel corrections defined in the X-Series Analyzer are applied to data captured from the analyzer. Any correction (Correction 1 - Correction 6) designated as On will be applied when Instrument User Corrections is set to On.

When using the Auto Range feature with the RF Input, Instrument User Corrections must be set to Off in order for Auto Range to work correctly.

This allows you to recall vendor corrections for external mixers into the X-Series Analyzer and have these corrections applied when using the 89600 VSA software to connect to the analyzer.

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

For E6680A there are 8 ports to select from (RFIO1 through RFIO8); for E6680E there are 4 ports to select from (RFIO1 through RFIO4).

RFIO1 - E6680A/E6680E
RFIO2 - E6680A/E6680E
RFIO3 - E6680A/E6680E
RFIO4 - E6680A/E6680E
RFIO5 - E6680A only
RFIO6 - E6680A only
RFIO7 - E6680A only
RFIO8 - E6680A only

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

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

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.

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

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

Other parameters may be visible, but only the parameters described in this topic are changeable through the VSA Input Extensions interface.

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

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