background image

12

|

ni.com

|

NI PXIe-5624R Calibration Procedure

Verifying Absolute Amplitude Accuracy

This procedure verifies the absolute amplitude accuracy of the NI 5624R input channel. 
Accuracy is specified using the calibration IP on the default 400 MHz acquisition FPGA image 
provided in the Multirecord Acquisition sample project. The 

Interactive Spectrum 

Acquisition (Host).vi

 provides a starting point for this procedure. The calibration IP 

equalizes the frequency response and corrects for losses. Because a digital downconverter 
(DDC) is used, multiple center frequencies are chosen in order to cover the entire specified 
bandwidth. The response across 400 MHz of bandwidth for each center frequency is measured.

This procedure requires the test setup and data collected in the 

Characterizing Power Splitter 

Balance

 section. Characterize the power splitter balance before running this procedure.

Zero the power sensor as described in the 

Zeroing the Power Sensor

 section prior to starting this 

procedure.

1.

Connect the signal generator RF OUT front panel connector to the input terminal of the 
power splitter using an SMA (m)-to-SMA (m) cable.

2.

Connect splitter output 1

 

directly to the power sensor input connector using the 

SMA (m)-to-N(f) adapter.

3.

Connect splitter output 2 to the SMA (f) end of the 6 dB attenuator using a 
3.5 mm (m)-to-3.5 mm (m) adapter.

Note

The power splitter configuration must match the configuration used in the 

Characterizing Power Splitter Balance

 procedure.

Summary of Contents for NI PXIe-5624

Page 1: ...PXIe 5624...

Page 2: ...PGA converts data from the ADC into quadrature I Q data This DSP shifts the frequency of decimates equalizes and calibrates the data before storing it into DRAM Use Interactive Spectrum Acquisition Ho...

Page 3: ...oftware from ni com downloads Documentation You might find the following documentation helpful as you perform the calibration procedure NI PXIe 5624R Getting Started Guide NI IF Digitizers Help NI PXI...

Page 4: ...for this procedure Verifying absolute amplitude accuracy Adjusting internal frequency reference B22 option needed for this procedure Adjusting absolute amplitude accuracy Frequency range 4 MHz to 2 00...

Page 5: ...adapter Huber Suhner 31_3 SMA 50 1 1 _UE or Fairview Microwave SM4236 Test system characterization Frequency range DC to 2 GHz Impedance 50 Return loss 23 dB 3 5 mm m to 3 5 mm m adapter Huber Suhner...

Page 6: ...each verification procedure insert a delay between configuring all devices and acquiring the measurement Adjust this delay depending on the instruments used but make sure it is at least 5 000 ms for t...

Page 7: ...e verification and adjustment procedures use test points from 5 MHz to 2 005 GHz in 5 MHz steps for the splitter balance characterization Frequencies in which harmonics alias on the fundamental freque...

Page 8: ...rrection function 7 Use the power sensor to measure the power at the frequency from step 6 8 Repeat steps 5 through 7 by updating the signal generator frequency from 5 MHz to 2 005 GHz in 5 MHz steps...

Page 9: ...e signal generator frequency from 5 MHz to 2 005 GHz in 5 MHz steps Record the resulting measurements as splitter output 1 power Each frequency should have a corresponding value 16 Calculate the split...

Page 10: ...ate self calibration using one of the following methods Click Self Calibrate in the upper right corner of MAX Right click the name of the device in the MAX configuration tree and select Self Calibrate...

Page 11: ...ference using a signal generator Use digitizer mode of the NI 5624R Use Interactive IF Acquisition Without DSP Host vi in the Multirecord Acquisition sample project as a starting point 1 Connect the s...

Page 12: ...gle Tone Information vi 5 Calculate the deviation using the following equation 6 Compare the value determined in step 5 to the verification test limits in the following table where initial accuracy 20...

Page 13: ...e across 400 MHz of bandwidth for each center frequency is measured This procedure requires the test setup and data collected in the Characterizing Power Splitter Balance section Characterize the powe...

Page 14: ...front panel connector The following figure illustrates the complete hardware setup Figure 4 Absolute Amplitude Accuracy Verification Cabling Diagram 1 Power Sensor 2 SMA m to N f Adapter 3 Power Spli...

Page 15: ...sult as measured input power Note Power sensor readings are in dBm not watts 9 Calculate the corrected input power using the following equation corrected input power measured input power splitter bala...

Page 16: ...R flash memory Successfully complete all required verifications or successfully complete reverification following adjustment prior to updating the calibration date and time on the NI 5624R Complete th...

Page 17: ...panel connector to the NI 5624R IF IN front panel connector using an SMA m to SMA m cable The following figure illustrates the hardware setup Figure 5 Internal Frequency Reference Adjustment Cabling...

Page 18: ...he power splitter balance characterization data for the correct frequency as the following frequencies are excluded from the adjustment procedure due to harmonics aliasing back on to the fundamental a...

Page 19: ...that the NI 5624R and the signal generator share a common reference The following steps assume you have connected the signal generator reference frequency REF OUT to the NI 5624R REF IN connector 6 C...

Page 20: ...plitter output 1 of the power splitter using the power sensor Record this value as the measured input power 12 Calculate the corrected input power using the following equation corrected input power me...

Page 21: ...NI Refer to the Worldwide Support and Services section for information about support resources or service requests Worldwide Support and Services The National Instruments website is your complete reso...

Reviews: