Receiver Gain

The receiver gain can be fixed. When the receiver gain is lower than expected, for example due to an unexpected spurious signal, this function allows you to fix the gain level to improve the dynamic range. The measurement speed is almost the same even if the range is fixed.

Note: Receiver Gain is not available on SA, MOD and MODX measurement class.

How to make Receiver Gain settings Use one of the following methods to set port power. The softkey is available on standard measurement class only.
Using Hardkey/SoftTab/Softkey	Using a mouse
Press Setup > Internal Hardware > Receiver Gain....	Click Instrument > Setup > Internal Hardware> Internal Hardware > Receiver Gain...

The analyzer has the independent error terms for high and low receiver settings. Each error terms can be monitored in Cal Set Viewer. A Cal Set has error terms without gain settings.

Note: The wideband/reference calibration set must have the same switched gain settings as the user cal set.

Calibration Time Reduction (Fixed Gain Calibration)

When receiver gain settings includes AUTO or combination of High and Low, the analyzer measures the error terms for both high and low settings automatically. Hence, the analyzer make sweeps three times in the calibration.

When receiver gain settings are all FIXED (high or low) and have same state for each source port, the VNA takes sweep for the calibration only one time for specified gain setting in order to reduce the calibration time.

For example, the following setting can reduce the calibration time.

Receiver gain setting		Receiver port
Receiver gain setting		1	2	3	4
Source Port	1	Low	High	Low	High
	2	Low	High	Low	High
	3	Low	High	Low	High
	4	Low	High	Low	High

Receiver gain setting		Receiver port
Receiver gain setting		1	2	3	4
Source Port	1	Low	High	High	High
	2	Low	High	High	High
	3	Low	High	High	High
	4	Low	High	High	High

Receiver Overload / ADC Overflow

When the receiver gain is set at Auto, the pre-measurement is done to select the proper range (HIGH or LOW). SENSe<cnum>:SOURce<sport>:RECeiver<rport>:GAIN:LIST? returns the information which range is used at each test point.

The receiver overload/ADC overflow may occur in the following conditions when the receiver gain is set at HIGH (including HIGH in AUTO setting)

During averaging, the receive gain will not be changed once the level is decided. Hence, the overload may occur if the level becomes bigger during averaging.

Receiver overload can be turned off in the preference.

E5081A Gain Coupling and E5081A/E5080B Receiver Gain Control for Application

Application	Receiver Gain Control	Gain Coupling (E5081A only)	RF Atten and IF Gain Control (E5081A only)	Note
Standard	Available	Available	Available
Pulse measurement	Available	Available	Available	Receiver Gain is set at LOW internally when AUTO
FOM	Available	Available	Available	Receiver Gain is set at RF:LOW, IF:AUTO internally when AUTO
Noise Figure, Noise Figure Converter in Noise Path (Bypass)	-	-	-	High/Medium/Low in Noise Figure dialog box
Noise Figure, Noise Figure Converter in S parameter	Disabled	Always Off	Available
Spectrum Analysis, Modulation, Modulation Converter	Disabled	Always Off	Available
SMC, SMC+Phase, Gain Compression, Gain Compression Converter, Active Hot Parameter	Disabled: Fixed at Auto	Available	Available	Receiver Gain is set at RF:LOW, IF:AUTO internally
Diff IQ, IMD, IMD Converter	Disabled: Fixed at Low	Available	Available
Enhanced TD	Disabled: Fixed at Low	Always On	Disable	Receiver Gain is set at RF:LOW, IF:LOW internally.

Receiver Gain dialog box help

E5080B

E5081A

Gain Coupling: When this is checked, the receiver gain can be set from Auto/High/Low. When this is not checked, the selection is disabled and RF attenuator and IF gain can be set independently at the Path Configurator.

Note: In E5081A 4 port configuration, the gain coupling is not applied to ports 3 and 4. Ports 3 and 4 are always coupled.

Note: In the gain coupling ON, the receiver gain for Bypass 20 GHz/44 GHz is fixed at a certain value according to the frequency.

Note: When the receiver gain is set at AUTO, the gain is fixed at LOW when the "RF In Switch" selects "External".

This dialog provides basic control receiver for a specific port.

This table consists of source port rows and receiver port columns. Each cell is corresponded to measurements in the active channel. (e.g. ‘Receiver port 1 – Source port 3’ is corresponded to S13, a1,3 and b1,3.)

The each cell sets the setting by the following drop down list.

Auto - (Default) Receiver gain is controlled automatically for each measurement points according to the input signal level.
High - Fix the gain setting at high
Low - Fix the gain setting at low

Set All Gains - Sets all cells at one time.

Receiver Gain for Segment Sweep dialog box help

In Sweep Segment Table Dialog, Check the check box of Receiver Gain.