Using RF Measurement Testbench
FOR MAKING APPLICATION UNDER PROVISIONS OF THE ILLINOIS ROOFING INDUSTRY LICENSING ACT 4. In item number 10, you must enter the designated qualifying party. This person must take and pass. DPR-RF INSTRUCTIONS REVISED 4/15 (INSTRUCTIONS TO 486-1223) RF INSTRUCTIONS - PAGE 2 OF 2. Purpose of the RF TestBench: RF TestBench can be used with or without a “development board”. Users of the MICRF405 transmitter or MICRF505/MICRF506 radio transceiver can use the RF TestBench to calculate fields in the control word to enter into the RF chip. Typical examples are: Get the complete control word to enter into the RF chip.
Use the RF Measurement testbench to verify the cumulative gain,noise figure, and nonlinearity (IP3) values of an RF-to-RF system.To use the testbench, create a system in the RF Budget Analyzer appand click Export
> Exportto Measurement Testbench
.
The testbench is made up of two subsystems:
RF Measurement Unit
Device Under Test
The testbench display shows the verified output values of gain,NF (noise figure), and IP3 (third-order intercept).
Device Under Test
The Device Under Test subsystem contains theRF system exported from the app.
RF Measurement Unit
The RF Measurement Unit subsystem consists ofa Simulink Controller and RF Blockset Circuit Envelope interface.The RF Blockset interface is used as input and output from the DUT.
RF Measurement Unit Parameters
Double-click the RF Measurement Unit subsystemblock to open the parameters.
Simulate noise (both stimulus and DUT internal) —Select this check box to enable noise modeling in the stimulus signalentering the DUT and inside the DUT.
Measured quantity — Choosethe quantity you want to verify from:
Gain
– Measure thetransducer gain of the converter, assuming a load of 50 ohm. If youchoose onlyI
or onlyQ
from Responsebranch, you see only half the value of the measured gain.NF
– Measure thenoise figure value at the output of the converter.IP3
– Measure theoutput or input third-order intercept (IP3).IP2
– Measure theoutput or input second-order intercept (IP2).DC Offset
– Measurethe DC level interference centered on the desired signal due to LOleakage mixing with input signal.
The contents in the Instructions tab changesaccording to the Measured quantity.
IP Type — Choose the typeof intercept points (IP) to measure:
Output referred
orInputreferred
.By default, the testbench measures
Output referred
.This option is available when you set the Measured quantity toIP2
orIP3
.
Parameters Tab
Input power amplitude (dBm) —Input power to the DUT. You can change the input power by manuallyspecifying or by turning the knob. When measuring
DCOffset
, this input field is Input RMS voltage(dBmV), because the Offset is measured in voltage units.The specified voltage represents the voltage falling on the inputports of the DUT.Input frequency (Hz) —Carrier frequency of the DUT.
Output frequency (Hz) —Output frequency of the DUT.
Baseband bandwidth (Hz) —Bandwidth of the input signal.
Ratio of test tone frequency to basebandbandwidth — Position of the test tones used forIP3 measurements. By default, the value is
1/8
.This option is available when you set the Measuredquantity to
IP2
,IP3
,orDC Offset
.
Instructions
Instructions for Gain Verification
Clear Simulate noise (both stimulus andDUT) for accurate gain verification. Select the check boxfor account for noise.
Change the Input power amplitude (dBm) orturn the knob to reduce the input power amplitude. For high inputpower, nonlinearities in the DUT can affect the gain measurements.
Instructions for NF Verification
The testbench verifies the spot NF calculated. Thiscalculation assumes a frequency-independent system within a givenbandwidth. To simulate a frequency-independent system and calculatethe correct NF value, reduce the baseband bandwidth until this conditionis fulfilled. In common RF systems, the bandwidth should be reducedbelow 1 kHz for NF testing.
Change Input power amplitude (dBm) orturn the knob to reduce or increase the input power amplitude. Forhigh input power, nonlinearities in the DUT can affect the NF measurements.For low input power, the signal is too close or below the noise floorof the system. As a result, the NF fails to converge.
Instructions for OIP3 and IIP3 Verification
Clear Simulate noise (both stimulus andDUT) for accurate OIP3 and IIP3 verification.
Change Input power amplitude (dBm) orturn the knob to reduce the input power amplitude. For high inputpower, higher-order nonlinearities in the DUT can affect the OIP3and IIP3 measurements.
For all measurement verifications using the testbench, you cannotcorrect result discrepancies using the RF Budget Analyzer app.The RF Blockset testbench provides true RF circuit simulation thatincorporates RF phenomena including saturation and interaction betweenmultiple tones and harmonics in nonlinear devices. These RF phenomenaare not yet incorporated in RF Budget Analyzer, leadingto some differences in the values between the testbench and the app.
Instructions for DC Offset Measurement
Clear Simulate noise (both stimulus andDUT) for accurate DC offset measurement.
Correct calculation of the DC offset assumes a frequency-independentsystem in the frequencies surrounding the test tones. Reduce the frequencyseparation between the test tones or reduce the baseband bandwidthuntil this condition is fulfilled. In common RF systems, the bandwidthis reduced below
1 KHz
for DC offset testing.. Change Input RMS voltage amplitude (dBmV) orturn the knob to reduce the input RMS voltage amplitude. For highinput RMS voltage, higher-order nonlinearities in the DUT can affectthe DC offset measurements
See Also
RF Budget Analyzer | Use RF Measurement Testbench for RF-to-IQ Converter | Using RF Measurement Testbench for IQ-to-RF Converter
Using RF Measurement Testbench for IQ-to-RF Converter
Use the RF Measurement Testbench to measure various quantitiesof an IQ-to-RF converter system. Measurable quantities include cumulativegain, noise figure, and nonlinearity (IP3) values. To open the testbenchand measure the quantities, use the RF Budget Analyzer appto create an RF system and then click Export
> Measurementtestbench
.
The testbench has two subsystems:
RF Measurement Unit
Device Under Test
The testbench display shows the measured output values of thegain, NF (noise figure), IP3 (third-order intercept), and other quantities.
![Testbench Testbench](http://literature.cdn.keysight.com/litweb/pdf/rfde2003c/rfdewtbwlan/images/wtbwlan05a.gif)
Device Under Test
The Device Under Test subsystem contains theRF system exported from the app.
RF Measurement Unit
The RF Measurement Unit subsystem consists ofa Simulink Controller and RF Blockset Circuit Envelope interface.The RF Blockset interface is used as input and output from the DUT.
RF Measurement Unit Parameters
Simulate noise (both stimulus and DUT) —Select this check box to enable noise modeling in the stimulus signalentering the DUT and inside the DUT.
Measured quantity — Choosethe quantity you want to measure:
Gain
– Measure thetransducer gain of the converter. If you choose onlyI
oronlyQ
from Stimulus branch,you only see half the value of the measured gain.Noise Floor
– Measurethe noise floor value of the converter.IP3
– Measure theoutput or input third-order intercept (IP3).IP2
– Measure theoutput or input second-order intercept (IP2).Carrier Feedthrough
–Measure the leakage of carrier tone into the RF spectrum due to imbalancesin the in-phase and quadrature phase inputs.Sideband Suppression
– Measure the sideband suppression required for the ideal cancellation of image signals around the RF output signal.
By default, the testbench measures
Gain
.The contents in the Instructions tab changesaccording to the Measured quantity value.IP Type – Choose the typeof intercept points (IP) to measure:
Output referred
orInputreferred
,By default, the testbench measures
Output referred
.This option is available when you set the Measured quantity toIP2
orIP3
.Injection Type – Choosethe local oscillator (LO) injection for sideband suppression:
Low-side
orHigh-side
,By default, the testbench measures
Low-side
.This option is available when you set the Measured quantity toSidebandSuppression
.Stimulus branch — Choosethe branch you want to use as input stimulus for the measurement:
I and Q (Q=-j*I)
— Signalmeasured is based on a combination of input signals. Quadrature inputis same as the in-phase input but is –90 degrees out of phase.I and Q (Q=j*I)
— Signalmeasured is based on a combination of input signals. Quadrature inputis same as the in-phase input but is 90 degrees out of phase.I only(Q=0)
— Signal measuredis only the output of the in-phase input signal. Gain measured usingthis input is only one quarter of the total output signal gain.Q only(I=0)
— Signal verifiedis only the output of the quadrature input signal. Gain measured usingthis input is only one quarter of the total output signal gain.
Parameters Tab
Input power amplitude (dBm) — Available input power to the DUT. You can change the input power by manually specifying or by turning the knob. When measuring Carrier Feedthrough, this input field is Input RMS voltage (dBmV), because the feedthrough is measured in voltage units. The specified voltage represents the voltage falling on the input ports of the DUT.
Input frequency (Hz) —Carrier frequency fed into the I and Q inputs of the DUT. By default,this frequency is by default one bandwidth above DC.
Output frequency (Hz) —Output frequency to measure the DUT.
Baseband bandwidth (Hz) —Bandwidth of the input signal.
Ratio of test tone frequency to basebandbandwidth — Position of the test tones used forIP3 measurements. By default, the value is
1/8
.This option is only available when you set Measuredquantity to
IP2
,IP3
,andCarrier Feedthrough
.
Instructions Tab
Instructions for Gain Measurement
Clear Simulate noise (both stimulus andDUT) for accurate gain measurement. Select the check boxfor account for noise.
Change the Input power amplitude (dBm) orturn the knob to reduce the input power amplitude. For high inputpower, nonlinearities in the DUT can affect the gain measurements.
Instructions for Noise Floor Measurement
The testbench measures the spot noise floor calculated.This calculation assumes a frequency-independent system within a givenbandwidth. To simulate a frequency-independent system and calculatethe correct noise floor value, reduce the baseband bandwidth untilthis condition is fulfilled. In common RF systems, the bandwidth isreduced below 1 kHz for noise floor testing.
Change Input power amplitude (dBm) orturn the knob to reduce or increase the input power amplitude. Forhigh input power, nonlinearities in the DUT can affect the noise floormeasurements.
Instructions for IP3 and IP2 Measurement
Clear Simulate noise (both stimulus andDUT) for accurate IP3 and IP2 measurement.
Change Input power amplitude (dBm) orturn the knob to reduce the input power amplitude. For high inputpower, higher-order nonlinearities in the DUT can affect the IP3 andIP2 measurements.
Instructions for Carrier Feedthrough Measurement
Clear Simulate noise (both stimulus andDUT) for accurate IP3 and IP2 measurement.
Change Input RMS voltage amplitude (dBmV) orturn the knob to reduce the input RMS voltage amplitude. For highinput RMS voltage, higher-order nonlinearities in the DUT can affectthe carrier feedthrough measurements
Correct calculation of the carrier feedthrough assumesa frequency-independent system in the frequencies surrounding thetest tones. Reduce the frequency separation between the test tonesor reduce the baseband bandwidth until this condition is fulfilled.In common RF systems, the bandwidth is reduced below
1 KHz
forcarrier feedthrough testing.
Instructions for Sideband Suppression Measurement
Clear Simulate noise (both stimulus andDUT) for accurate IP3 and IP2 measurement.
Change Input power amplitude (dBm) orturn the knob to reduce the input power amplitude. For high inputpower, higher-order nonlinearities in the DUT can affect the sidebandsuppression measurement.
For all measurements using the testbench, you cannot correctresult discrepancies using the RF Budget Analyzer app.The RF Blockset testbench provides true RF circuit simulation thatincorporates RF phenomena including saturation and interaction betweenmultiple tones and harmonics in nonlinear devices. These RF phenomenaare not incorporated in RF Budget Analyzer, leading tosome differences in the values between the testbench and the app.