R. A. Wood Associates QuickNews

RF Path Analysis Toolkit 1.4 Released!

We just released an update to RF Path Analysis Toolkit (Version 1.4). The release contains some nice time saving features and improvements:

• Drag and Drop RF Components: In the RF Path Builder display, you can now drag and drop RF components in the path table rows. This makes it easy to move RF components around in the RF path. Previously if you wanted to move an RF component, you had to delete the RF component, and then look it up again in the library to insert it into a new location.
• Sub paths: You can now define an RF Path as a series of sub paths, which are individual RF path files. This saves potential errors and time in updating many RF paths containing the same path information. Previously, you could only manually load sub paths into an RF path file. Now they can be defined within the RF path file itself.
• Export to Excel options: Now you can select the option to leave the detailed RF path analysis spreadsheet open after "Export to Excel" is selected. Previously the detailed RF path analysis spreadsheet was closed after "Export to Excel". This is convenient for viewing the detailed results quickly as you are building RF paths.
• More information in the RF Path Builder display: As you are building an RF path in the RF Path Builder, you can now see the following parameters:
• Device Nominal Gain
• Cumulative Gain to Device Output
• Device Noise Figure
• Cumulative Noise Figure to Device Output
• Signal 1 Power at Device Output
• Signal 2 Power at Device Output
• Device Third Order Output Intercept Point
• Cumulative Third Order Input Intercept Point
• Device 1 dB Output Compression Point
• Signal 2 Delta from Device 1 dB Compression Point
• Third Order Spurs at Device Output (new!)
• Cumulative 1 dB Input Compression Point (new!)
These new parameters are helpful when designing RF paths with difficult dynamic range requirements, and provide more insight into dynamic range contributors as you are building the RF path.
• Path File Save and Load folders: You can now specify the default directory for saving and loading RF path files. Previously this was fixed to the "Level 1" directory.
• Revised template spreadsheets: We've updated and improved the template detailed analysis spreadsheets. There are now two template spreadsheets:
• RFPATTemplate4-2.xls is a simplified (but still very useful) RF path analysis spreadsheets for receivers and transmitters. Antenna gains can not be accurately incorporated into the model. Sensitivity calculations are based on the receiver RF components only.
• RFPATTemplate6-2.xls is a more advanced RF path analysis spreadsheet. This template allows for separate RF component "signal gain" and "noise gain" parameters. This allows the spreadsheet to show radiated sensitivity, because antenna gains can be taken into account (antennas have "signal gain" but no "noise gain"). Basic RF components have the same "signal gain" and "noise gain".
• File Path dialog boxes should be more descriptive and helpful.
• Other changes to the user interface/display to help clarify the operation of the program.

Upgrades are free to previously registered users. Download the new version (http://www.rawood.com/software_products/), give it a try, and let us know what you think!
Thanks! -Bob Wood

Demo Version of RFSpecTest Released

Hello Fellow Test Engineers and Managers:

• Are you frustrated with the time and effort required to test your RF and microwave components?
• Are you upset with the errors and mistakes associated with manual testing?
• Is developing your own computer automated test software beyond your budget?

• Do you already have test equipment capable of GPIB control?
• 1, 2, or 3 RF Signal Generators?
• A Spectrum Analyzer?
• An RF Power Meter?
• Wouldn't it be great if there was a software program already developed that could be used right away to start making automated RF measurements?

We have a software program, called RFSpecTest, which has many built-in computer automated RF/microwave tests already developed. We've just created a demonstration version that can be downloaded and evaluated. More information is available from our software information page. Download the demo, and try out the tests and interfaces available. We also have some sample measurement files you can load into the program. Give it a try and let us know what you think!

Thanks! Bob Wood

Painless Extraction 2.0 has been released!

Apple TV, iPhone... How many more technological marvels can we take this week?

We decided to add our own surprise to a big technology week with the release of Painless Extraction 2.0!

Painless Extraction 2.0 adds some great new features to the previous version:

• Capability to extract 1-4 channels of measurements from HP (Agilent) 8757 Series Scalar Analyzers,
• A new script creation page that allows the user to set up test scripts, which compare the measurements against user-defined test limits, and a test summary report is created.

8757 Series Scalar Analyzers:

Painless Extraction 2.0 has been designed to extract up to 4 channel measurements from HP 8757 series scalar analyzers. The extracted data is stored into the magnitude arrays of the S2P files (Phase arrays are zeroed out). Up to 4 channels can be extracted from the scalar analyzers. The 4 channels could be S-parameters (S11, S21), or they could be any channel setup from the scalar analyzer (A/R, B/R, C/R, A/B, etc.) Whatever the user sets up on the scalar analyzer channels, Painless Extraction retrieves the data from the analyzer, analyzes it, and stores it in "S2P format" files for future retrieval and data analysis.

Now the same capability we've provided for network analyzers (HP 8720 Series, HP 8510 Series, HP 8753 Series) is available for HP 8757 Series scalar analyzers. (Please note that we have verified the program specifically with a 4-Channel HP 8757C scalar analyzer.)

Statistical Analysis and Test Scripts:

We've added a new "tab" which can be used to perform statistical analysis on the various measurement channels. For example, let's say you have the network or scalar analyzer set up to take S11 (return loss) and S21 (gain) measurements over the frequency band of 1.0 to 3.0 GHz. You can very quickly set up a test script which sets the Pass/Fail limits for the S21/gain measurements, and sets up the Pass/Fail limits for the S11/return loss measurements. Now when you connect the amplifier, and the measurements on the analyzer are set up, you can retrieve the measurements from the analyzer and compare the measurements with the test limits and make Pass/Fail determinations. You can then save the test summary report in a tab-separated text format, which can be imported into spreadsheet programs (Excel and others).

This is a great feature if you are using a network analyzer or scalar analyzer for high volume production testing!

More information is available from our software products page, and the associated links for downloading a demo version of this program.

Thanks to Amelia for her great support in updating this program.
Bob Wood

Painless Extraction 2.0 Coming Soon

Hello Everybody

We just wanted to give you a quick "heads up" about the upcoming version 2.0 of Painless Extraction. We have added some pretty significant features, such as:

• The capability to retrieve S-Parameters or other Channels 1-4 measurements from HP8757C Scalar Analyzers. We believe this will open up a whole new market for this program.
• The capability to create a quick test script that will allow the user to set various test parameters for the retrieved data, such as average gain, minimum gain, maximum gain, P-P flatness, RMS, standard deviation, best fit line slope, and many others. The measured data from the network or scalar analyzer is then compared against these test parameters, and Pass/Fail results are reported. This is a great feature for production testing, or testing multiple parts with the same test parameters.

We expect to have this version released within the next 2 weeks. Please stop by again, try it out, and let us know what you think about the new version.

Thanks!

Bob Wood

New Integrated RF Test Rack Designed and Delivered

On September 15 2006, R. A. Wood Associates delivered the first two of 15 complete Integrated RF Test Racks. The Integrated RF Test Rack provided a complete solution for complete automated testing of 7 RF/Digital modules. All equipment was controlled through GPIB interfaces. All automated test software was written in National Instruments LabVIEW by R. A. Wood Associates. RFSpecTest was used in "script" mode to perform most of the RF measurements. The rack consisted of:

• 2 Signal Generators (one for RF signals, one for LO signals)
• 1 Spectrum Analyzer (for measuring RF signal amplitudes and frequencies)
• 1 Multimeter (for monitoring resistances and voltages at various points on the modules)
• 3 Power Supplies (for providing DC power to the modules under test)
• A rack mount PC with GPIB and Digital I/O cards, loaded with software for controlling test equipment and reporting test results
• A rack mount interruptible power supply (UPS)
• R. A. Wood Associates Automated RF Test Fixture
• Laser Bar Code Reader (for reading and automatic entry of module serial numbers)
• A 19" Flat Panel Display (mounted on movable monitor arm)
• Keyboard and Mouse in a slide-out ergonomic tray

The full rack was designed to be a comfortable testing environment, as well as easy to maintain. Equipment is easy to remove if needed with minimal interference to other equipment.

More information about the Integrated RF Test Rack is available from this link.

Fonts updated in all software programs (Windows XP users)

For some Windows XP users, the fonts used in our software programs were not available in Windows XP, causing the front panel fonts to be substituted with other fonts. This caused some displays to become overcrowded. The newer versions use a font that is available in all Windows versions. You can download the newer versions if you have had trouble with the front panel display fonts. Go to our software download page for the latest updates

R. A. Wood Associates at MTT Symposium

R. A. Wood Associates demonstrated our RFSpecTest software product at MTT Symposium in Philadelphia, PA during June 10-12, 2003. See our Press Release for more info.

New Software Releases with integrated payment and registration!

We've updated our software products to improve the payment and registration process. You can now pay for registration directly through PayPal, E-mail, or using a WWW form. This feature is built in to the software programs. The User Name and Registration Key are sent to us electronically. After payment is confirmed, we will send you a Registration Number electronically via E-mail. This should make the whole payment and registration process smoother and simpler.

R. A. Wood Associates Demonstrated Computer Automated RF Test Software Suite at NI Week Aug 13-16, 2002 in Austin, Texas:

R. A. Wood Associates introduced their latest computer automated RF test software suite, RFSpecTest, at National Instruments (NI) Week, August 13-16. See Press release. The test software suite is centered around NI's latest RF product, the NI 5660 Spectrum Analyzer. Automated testing for gain, two tone intermodulation products, gain compression, relative measurements, and others was demonstrated for amplifiers, mixers, switches, filters, attenuators, RF integrated circuits and more. Thanks to all who stopped by to see our new product! A picture of our booth and computer automated test setup at NI Week. For an overview of the of RFSpecTest, select this link (1.7 MB pdf file).

Upgrade and Repair Services

Upgrade and Repair Services

• One of our clients had received some RF modules that were functionally working, but the performance was not meeting system performance requirements. We analyzed the modules, determined the changes needed to meet system performance requirements, and upgraded the RF modules for our customer. Some of the highlights of this effort:
  • New RF components were specified, sent out for quotes, and purchased from vendors
  • Improved 1 dB compression points
  • Reduced noise power levels
  • Improved P-P flatness
  • Automated RF test software was developed to perform final acceptance tests
  • Acceptance test reports were created and delivered to the customer for each upgraded RF module
  • Some of the modules were RF components interconnected with coaxial RF cables
  • Some of the modules were surface mount components on microstrip medium
  • The system performance was greatly enhanced by these upgraded RF modules

MetalTest Systems available

We have developed a computer automated Metal Tester for testing metals using thermo-electric measurements from an Acromag meter, a PC A/D converter board, and LabVIEW software. For more information, go to this page.

Computer Automated Test System for LDMOS Wireless RF Power Amplifiers

Computer Automated Test System for LDMOS Wireless RF Power Amplifiers

• We provided an automated RF Test System to provide computer automated testing of LDMOS RF Power Amplifiers. The amplifiers are used in base stations for AMPS, PCS, UMTS systems. Software was developed using National Instruments LabVIEW
• RF Measurements provided at several Output Power Levels
  • Gain
  • Gain Compression (servoed to X dB gain compression)
  • Output Power (servoed to a specified power)
  • Intermodulation Products (IMD)
  • Adjacent Channel Power (ACP)
  • Return Loss
• DC Measurements included:
  • IDQ Servo (Adjust Vgg to achieve desired Idd current)
  • Idd measurement at RF Output Power
  • Ronq
  • Ronh
  • Gmq
  • Gmh
• Other Measurements
  • Efficiency
  • Power Added Efficiency (PAE)
• For an overview presentation of the LDMOS Automated Test System:
  • 3.8 MB pdf file, good for printing
  • 1 MB pdf file, good for screen viewing

MetalTest Software

MetalTest Software

A software program was developed using LabVIEW, a graphical programming language from National Instruments. The program runs on a PC and is connected to an Acromag Metal Tester using a PC Data Acquisition board. The program compares the readings gathered from the Metal Tester to readings in a database for various alloys. The program then gave a readout of what metal alloy most closely coincided with the metal being tested. The program also provided probability levels (T-Test) to show confidences against the various other possible alloys in the database. The MetalTest System is currently being used to recycle aircraft engine machining scrap and is helping the company earn hundreds of thousands of dollars in metal reclamation sales.

Click here for more information!

Two Tone Third Order Output Intercept Point Measurements

Two Tone Third Order Output Intercept Point Measurements

This LabVIEW panel shows the results of computer automated Two-Tone Third Order Output Intercept Point measurements for a PCS band RF amplifier. Measurements were performed using two programmable signal generators and a spectrum analyzer. A power meter was used to calibrate the input and output cables and connectors, and the spectrum analyzer amplitude readings. This panel design is tailored toward an "engineering evaluation" environment, instead of a "production test" environment.

1 dB Output Gain Compression Point Measurements

1 dB Output Gain Compression Point Measurements

This LabVIEW panel shows the results of a computer automated 1 dB Output Gain Compression Point measurements for a PCS band RF amplifier. Measurements were performed using a programmable signal generator and a spectrum analyzer. A power meter was used to calibrate the input and output cables and connectors, and the spectrum analyzer amplitude readings. This panel design is tailored toward an "engineering evaluation" environment, instead of a "production test" environment. This is just one example of the types of automated RF measurements that can be performed using LabVIEW.

Computer Automated Noise Figure Measurements

LabVIEW Example - Computer Automated Noise Figure Measurements

This LabVIEW panel shows the results of computer automated Noise Figure measurements for a PCS band RF amplifier. Measurements were performed using a HP-8970B Noise Figure Meter. This panel design is tailored toward an "engineering evaluation" environment, compared to a "production test" environment. This is just one example of the types of automated RF measurements that can be performed using LabVIEW.

Cryogenic Cooled RF Amplifier Development for PCS Application

Cryogenic Cooled RF Amplifier Development for PCS Application

• We helped a company involved in Cryogenic packaging to design, verify and test a cryogenic cooled LNA package. We used LabVIEW software to develop a complete computer automated test station, providing the following measurements controlled by LabVIEW via GPIB interfaces:
  • Full 2-Port S-Parameters
  • Noise Figure vs. Frequency
  • 1 dB Output Compression Point vs Frequency
  • Two Tone Third Order Output Intercept Point vs Frequency
• The test setup was designed so that a lot of detailed testing could be completed in a very short time (while the device was in a vacuum and being cooled with liquid Nitrogen. The test equipment being controlled included:
  • HP Network Analyzer
  • HP Noise Figure Meter
  • HP Power Meter
  • HP Signal Generator
  • HP Spectrum Analyzer
• All measured data was stored electronically in electronic format for importing into spreadsheet programs for further analysis and plotting of results.....

Software Controlled Laser Power Meter Interface

Software Controlled Laser Power Meter Interface

 

• Software was developed to provide a computer-controlled interface to a Universal Radiometer. The Universal Radiometer is a piece of test equipment used to measure laser power. The device was controlled by a PC serial port. The software was developed using National Instruments LabVIEW graphical programming language.
• All instrument controls are sent from the screen display through the PC serial port to the test equipment.
• Data from the test equipment is sent via the PC serial port to the computer and analyzed and displayed on the screen display.
• Measured data can be stored to an external file in Microsoft Excel or other spreadsheet compatible format.
• Measurement statistics are calculated and displayed in real time

Spectrum Analyzer Instrument Driver

LabVIEW Example - Spectrum Analyzer Instrument Driver

This LabVIEW panel shows an software controlled instrument driver that is utilized for HP Spectrum Analyzers. The software has been used on HP-8566B and HP-8593E Series Spectrum Analyzers. All front panel controls are translated to GPIB commands to control the equipment over a GPIB interface. The output readings are Marker Frequency and Marker Amplitude. Various options are included for locating and finding RF signals.

Tuning Station Example (Audible Feedback)

Tuning Station Example (Audible Feedback)

In this example an amplifier tuning station provides audible feedback to aid the technician in tuning the amplifier within its specified performance limits. The technician can tune the amplifier under a microscope, using the audio tones to indicate how close the device meets its specified performance window. The technician does not have to look up from his work to check an instrument panel to determine the results of his/her tuning.

R. A. Wood Associates can custom develop automated test software for your particular needs in your test station. We can provide and implement ideas to enhance your productivity.

Statistical Data Reduction and Analysis

Statistical Data Reduction and Analysis

R. A. Wood Associates Software can save valuable test and debug time by analyzing and summarizing large quantities of data. This example shows the result of taking 500 frequency readings from a Digital Frequency Discriminator (DFD) under low signal to noise ratio conditions. The DFD frequency error is plotted on the graph vs input frequency. The statistics of the frequency error are evaluated in the Test Summary and compared against the specifications. The test operator obtains immediate feedback from the results of the measurements.

User Friendly Test System Interface

User Friendly Test System Interface

 

The LabVIEW software developed by R. A. Wood Associates provides a user friendly interface to the automated test setup. The computer screen is the Test Panel, where input test parameters are entered or selected. Selection switches can be placed on the screen to control the hardware being tested.

After the test is completed, the output data is summarized, plotted, and printed out. Actual test data points can be stored in data files if needed.

Typical Automated Test Setup (Microwave Test)

Typical Automated Test Setup (Microwave Test)

This diagram shows a typical computer automated test setup. In this application, a microwave device is tested using microwave test equipment such as the signal generator, spectrum analyzer, and power meter. The digital I/O controller provides the logic controls for the Device Under Test while the logic analyzer reads digital information from the device.

The computer acts as the automated test controller. It controls the microwave test equipment to provide stimulus and measurements to and from the Device Under Test. Digital control is passed from the computer through the digital I/O board. Digital output data is passed from the logic analyzer to the computer.

The R. A. Wood Associates software will control the testing and analyze the measurements. Typical measurements may include gain, noise figure, gain compression, spurious signals, filter rejection and amplitude accuracy. The measured data is then summarized, eliminating the need for manual data reduction. Output data can be stored in data files for further analysis and evaluation.

Instantaneous Frequency Measurement (IFM)

LabVIEW Example - Instantaneous Frequency Measurement (IFM)

2. Explanation of Parameters on Data Plots

An explanation of the parameters on the data plots shown in Appendix A is provided below.

2.1. Start, Stop and Step Frequencies

Frequencies used for test data.

2.2. Noise Power (dBm)

The wideband noise power across the 2 to 6 GHz frequency band. The noise source was provided by cascading several 2-6 GHz amplifiers together and tuning the amps for flat gain across the frequency band. The noise power was measured using a broadband power meter.

In the NB filter measurements, the noise power represents the noise power across the NB filter bandwidth measured using a broadband power meter.

2.3. SNR

The Signal to Noise Ratio at the IFM input. The SNR was achieved by combining the signal and noise and adjusting the input RF signal relative to the wideband noise power measured.

2.4. Pulsewidth (nSec)

The pulsewidth of the IFM enable (Freq Strobe). The pulsewidth determines how many samples are received from the IFM at each frequency. There will be 1 frequency reading or average frequency output every 100 nSec over the IFM enable time

2.5. Data < 4 MHz

The percentage of frequency readings that were less than 4 MHz error were calculated. The readings were flagged correctly if the Gross Freq Error Flag was 0, and the PMOP Freq Error Flag was 0, and the Quality Bits were greater than or equal to the Quality Bit Threshold. The readings were flagged incorrectly if the Gross Freq Error Flag was 1, or the PMOP Freq Error Flag was 1, or the Quality Bits were less than the Quality Bit Threshold. Percentages of data flagged correctly and incorrectly were summarized.

2.6. Data 4 - 20 MHz

The percentage of frequency readings that were between 4 and 20 MHz error were calculated. The readings were flagged correctly if the Gross Freq Error Flag was 0, and the PMOP Freq Error Flag was 0, and the Quality Bits were less than the Quality Bit Threshold. The readings were flagged incorrectly if the Gross Freq Error Flag was 1, or the PMOP Freq Error Flag was 1, or the Quality Bits were greater than or equal to the Quality Bit Threshold. Percentages of data flagged correctly and incorrectly were summarized.

2.7. Data > 20 MHz

The percentage of frequency readings that were> 20 MHz error were calculated. The readings were flagged correctly if the Gross Freq Error Flag was 1, or the PMOP Freq Error Flag was 1. The readings were flagged incorrectly if the Gross Freq Error Flag was 0, and the PMOP Freq Error Flag was 0. Percentages of data flagged correctly and incorrectly were summarized.

2.8. Quality Bit Threshold

The three quality bits comparing the last two correlator channels is an output of the IFM with each frequency reading. A seven (111) represents high correlation, and 0 (000) represents poor correlation between the correlator channels. The quality bits were compared against the Quality Bit Threshold to flag frequency readings in the range 4 to 20 MHz error. If the quality bits were less than the Quality Bit Threshold, and the Gross Freq Error and PMOP Freq Error were at logic 0, then the data would be flagged as a fine frequency error (4 - 20 MHz).

2.9. Gross Freq Error Threshold

The Gross Freq Error Threshold was programmed as an input to the IFM. If the worst case of all the correlator compares in the IFM is less than the Gross Freq Error Threshold, then the Gross Freq Error Flag is set to logic 1. The Gross Freq Error Flag is used to flagged errors > 20 MHz. See Appendix B for further information.

2.10. Gross PMOP Count Threshold

The Gross PMOP Count Threshold represents the number of IFM samples where the PMOP flag was looked at to determine low SNR conditions. If the the PMOP Flag was logic 1 at or before the Gross PMOP Count Threshold (no. of samples), then the PMOP Freq Error Flag would be set to logic 1. The PMOP Freq Error Flag is used to flag errors > 20 MHz. See Appendix B for further information.

2.11. PMOP Threshold

The type of phase modulation being detected (90° / 180°).

2.12. Sample No.

The plot shows results for the Sample No. on the left side of the plot. Note: the software program starts all arrays with element "0". Therefore, Sample 0 corresponds to the first frequency reading, Sample 1 corresponds to the second frequency average, etc.

2.13. Data Plots

The data plots on each page show test results for the Sample No. shown. The top trace shows the Quality Bits for each frequency reading. a 7 (111) represents good quality and 0 (000) represents poor quality.

The second trace shows the frequency error across the frequency band (MHz)

The third trace shows the Gross Freq Error Flag for each frequency reading. The trace is offset at -5 for clarity. When the value is -5, the flag is logic 0. When the value is -4, the flag is logic 1.

The fourth trace is the PMOP Freq Error Flag. If the PMOP flag is logic 1 in less than the Gross PMOP Count Threshold sample no, the PMOP Freq Error Flag is set to Logic 1. This trace is offset at -10 for clarity.

The fifth trace is the FMOP Flag, offset at -15 for clarity.