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The 41st Institute of China Electronics Technology Group Corporation
Abstract：In the Paper，the author introduces an embedded design verification test based on specific chips to solve the technical problems of microwave circuit test and fault diagnosis.The author explains embedded design of microwave circuit modules and approach of hardware design and software design，and finally verifies the embedded design of microwave circuit modules based on specific chips.
Keywords：Specific Chips；Microwave Circuit Modules；Embedded Test；BTT；Fault Injection
I.Introduction
At present，microwave circuit modules are widely applied in electronic equipment.For example，active phased array radar system has hundreds of T/R modules，at least，as core modules，and ten thousands at most.Each T/R module has tens of IC，which is typical microwave circuit module.
If there is no testability，it is difficult to find IC fault by peripheral test during the producing and debugging and it is also impossible to immediately or accurately judge the fault module and fault position.Therefore，embedded test and testable design of microwave circuit modules are urgent.
In foreign countries，testability is the key technical specification when US army order and design electronic equipment；testability design technology is adopted in research and production of foreign electronic equipments such as radar.However，people focus on testability design of digital circuit and analog circuit，testability design of microwave modules is seldom mentioned.
In China，microwave circuit modules have simple functional structure，and the fault is easy to judge.However，with the development of microwave monolithic integration hybrid integration，the functional structure of microwave circuit modules become more and more complicated，and it is impossible to judge fault without testability design which is the bottleneck for equipments’long-term running，producing，debugging and maintaining.Therefore，a method of embedded design verification test of microwave circuit modules based on specific chips is introduced to solve the technical problems of microwave circuit test and fault diagnosis and provide technical support for the fault location，fault dingoes，fault isolation and fault maintenance of RF and microwave subsystem of electronic equipment system.The maintaining expense is reduced and technical support efficiency is improved.
II.The Embedded Test Design of Microwave Circuit Modules The embedded design and testability design of microwave circuit should follow two principles.Firstly，the reliability of embedded test circuit is higher than that of tested microwave functional circuit，so we should carefully consider the reliability by using simple and mature circuit and reducing components during design of embedded test circuit.Secondly，if embedded test circuit has fault，microwave circuit modules should be ensured to work normally.Coupler instead of switch should be used in the interface of embedded test circuit and microwave modules.
The electronic subsystem is made of microwave circuit modules and the functional structure of microwave circuits are shown as follows：
According to Figure 1，microwave circuit modules（MCM） are mainly made of units of microwave components and microwave offset backplane.The former can realize the functions of filter，frequency division，mixing，amplification and attenuation；the latter is used in signal transmission，power conversion stabilization，BIT control and conditional information acquisition.Embedded test and testability design mean to set monitoring points in position of microwave components and previously make monitoring sensor circuit to monitor frequency，power and modulation waves of microwave circuit.According to sensor circuit，the power of microwave signals are divided，and these signals become analog signals with low frequency which can be transferred to unit of microwave offset backplane.Analog embedded chips and embedded controlling chips can deal with the analog signals，such as storage，fault indication and data uploading.The power and signals in DC operating points can also make condition monitoring and data acquisition by analog embedded chips and embedded controlling chips.The embedded controlling chips mainly control BIT of microwave modules.Besides，microwave embedded chips，analog embedded chips and embedded controlling chips are finally customized into specific chips，which are mounted in right position of microwave circuit modules to achieve the aim of embedded test design.
III.Embedded Test Design of Microwave Circuit Modules Based on Specific Chips
A.The design of the Hardware
The microwave modules with excellent embedded test and testability design can monitor and acquire the microwave parameter information of microwave functional circuit，such as，frequency，power and modulation waves.Secondly，they can monitor and acquire analog information of analog circuit of power supply and DC operating points.Thirdly，they have functions of power up BIT，cyclical BIT and initiating BIT of microwave circuit modules.Besides，they have functions of information storage，test information fusion and analysis；functions of fault diagnosis，isolation and location；function of information interaction by standard interface bus.Therefore，in the paper，the author designs the principle diagram of the embedded test and testability design of microwave modules.It is shown in Figure 2. In Figure 2，the microwave circuit modules are divided into yellow part and green part.The yellow part is unit of microwave components and the green part is that of microwave offset backplane.Embedded test and testability design of microwave modules exit in yellow part.Microwave embedded chips can be previously put into the right position of microwave component，and microwave signals are turned to analog signals with low frequency which is transferred into microwave offset backplane in green area.Analog signals with low frequency are previously disposed into the signals which are suitable to test analog chips，and then the signals are sent into analog embedded test chips by signal test channel and become digital analog signals.Once again，the signals are sent into embedded test chips to realize the fault isolation，location，conditional monitoring display，storage and uploading of microwave circuit.The power supply and DC operating points of microwave offset backplane can also realize fault isolation，location，conditional monitoring display，storage and uploading of analog circuit by preprocessing，analog chips and embedded control chips.Therefore，embedded test and testable design of microwave circuit modules should complete three kinds of design including testability design of microwave circuit unit，analog circuit unit and the design of embedded control chips.
Testability design of microwave circuit unit mainly refers to design circuit to realize power division of microwave signals，which can be changed into analog signals with low frequency to be output from microwave component unit.Specifically，microwave embedded chips turn microwave signals into analog signals with low frequency，and by using feed through capacitor these signals are transferred into microwave offset backplane unit to do follow-up processing.According to frequency，power and modulation waves of embedded microwave signals，the author designs three embedded chip circuit and makes them into specific chips to mount in the microwave circuit.
Testability design of analog circuit refers to design analog embedded chips to acquire or monitor node-information and condition of analog functional circuit in microwave offset backplane unit.Analog embedded chips will be customized into specific analog chips and different channels can be designed according to actual requirements of detection nodes.The author designs 32 channels and each channel has three instrumented functions of analog signal acquisition.They are Digitizer，digital voltmeter and frequency meter，and respectively realize embedded test of multi-channel analog signals such as wave forms，amplitude and frequency. The designers chose FPGA，Virtex-5 series in Xilinx to realize embedded control chips.The FPGA has embedded CPU hardcore POWERPC440，with fast arithmetic capability，high performance IO，flexible configuration.By protocol conversion，CPU can receive upper-computer commands and data information from back-plane bus.Depending on different information，CPU can load，unload，read or update programs and data，or operate BIT commands and other actions.Besides，FPGA definite registers，for example，command register，command decoder，state register，address register and data register，to register，decode CPU commands，and cache data of external memory.Peripheral circuit of CPU is mainly used to load FPGA program，storage operating system，applied software，database，table，fault records，memory，power supply and clock.The author develops IP based on FPGA and then customizes the specific chips when controller is debugged.
B.The design of the Software
1）Hierarchical Structure of software
The embedded test software in this paper is named as “E-BIT software”.E-BIT software is designed modules as hierarchical structure and is made of five layers from bottom to top.They are hardware，embedded operating system，BIT drive program，BIT applied program and BIT interface.The hierarchical structure is shown in Figure 3.
The hardware platform of E-BIT software uses PowerPC440 from Motorola as core processor.Peripheral equipment has a Flash Memory（M25P128）with 128Mbit which used to store starting code，Linux，user’s program，RS232 serial port，CAN bus interface and JTAG interface.
Embedded operating system lies in hardware and applied program and is responsible for task scheduling and real-time applied program management.Embedded operating system includes Boot loader，customized Linux operating system kernel and file system.It is a carrier providing good condition to manage configuration files and operate applied software.
Drive program include customized peripheral drive program and test-resource drive program.Because in Linux，all the equipment drivers can be statically connected and dynamically loaded，in order to improve CPU efficiency，peripheral drive program use static connection and test-resource drive program upload information dynamically according to running status.
Applied program have program sets，system management software，internal self-checking software，upgrading maintenance software，query information software and information processing software.BIT program sets include power embedded test program，cyclical embedded test program and initiating embedded test program. BIT interface is mainly used to operate general control software；communicate with upper computer；receive information commands and process them in real time；start applied programs by workflow.
2）BIT Test
BIT service can conduct embedded test of microwave circuit modules and read results.Embedded test include PBIT，CBIT and IBIT.By using microwave embedded chips，analog embedded chips and embedded control chips circuit，it can acquire frequency，power and modulation waves of microwave functional circuit and analog functional circuit.
3）Software Flow
The operating flow of E-BIT software is shown in Figure 4.
When microwave circuit modules are in normal working condition，general control software will run control interface and come into routine of receiving/sending message.These message commands come from interactive interface of general control software and internal/external communication bus of other softwares.General control will analyze message commands in time and classify them.Tasks have setting CBIT running status，running IBIT，internal self-checking software，upgrading maintenance software，query information software，system management software and information processing software.When general control software run the sub-modules software，they will not trace the running status.
General software will run CBIT cyclically in spare time.The running status of CBIT is done/ undone，or whether running interval can be changed in time or not.
IV.Embedded Design Verification Test of Microwave Circuit Modules Based on Specific Chips
In this paper，the author chooses digital signal processing modules and frequency-multiplication leveled amplifying modules of vector network analyzer as the verification object，which is called “instrument king” with the highest complexity and the most difficult technology.Using embedded specific chips，connecting software platform and diagnosis test program，the author roundly verifies the test information acquisition，transmission，diagnosis and diagnostic results in operating modes of PBIT，CBIT and IBIT.
Verification platform is made up of hardware and software.Hardware includes the vector network analyzer of digital signal processing module and frequency-multiplication leveled amplifying modules with excellent testability design.Besides，the instrument has embedded diagnosis computer.The verification platform is shown is Figure 5.
Verification platform software are the developed software platform and test diagnostic program.The main surface and subsurface of software platform are shown as follows：shown in Figure 6. Instruments required in verification are listed as follows：
From test verification and test results，embedded design verification test of microwave circuit modules get good effect in vector network analyzer.Running status of each test node can be directly observed in verification interface and light-sound alarm system will be operated if there is fault.The acquisition data are consistent with actual test data，which can prove that the embedded test chips have satisfied requirement of performance index and have good stability.In addition，data query，data browse and run-chart analysis can be done by embedded test software to analyze test information and get diagnostic results.Therefore，the embedded design verification test based on specific chips has some feasibility.
V.conclusion
In the paper，embedded specific chips with small size，little weight and low consumption，can not only reduce the space taken up by embedded test circuit in functional circuit board，but can also improve the stability of embedded circuit in microwave circuit modules and solve the technical problems of microwave circuit test and fault diagnosis.
References
[1]Mohrenschildt M V.Hybrid Systems:Solutions,Stability,Control.Proceedings of the 2000 American Control Conference,2000,1:692-698.
[2]Lafferriere G,Paas G J,Sastry S.Reachability Analysis of Hybrid Systems Using Bisimulations.Proceedings of the 37th IEEE Conference on Decision and Control,1998,2:1623-1628.
[3]Kmenta S,Ishii K.Scenario-Based FMEA:A Life Cycle Cost Perspective.ASME DETC,2000.
[4]Chang C L,Liu P H,Wei C C.Failure Mode and Effects Analysis Using Grey Theory.Integrated Manufacturing Systems,2001,12(3):211-216.
[5]Oakland S F.Considerations for Implementing IEEE 1149.1 on System-On-A-Chip Integrated Circuits.International Test Conference,2000:628-637.
作者简介：郭荣斌（1971—），男，高级工程师，中国电子科技集团公司第41研究所室主任，主要从事电子测试仪器方面的研发和部门的管理工作。
Abstract：In the Paper，the author introduces an embedded design verification test based on specific chips to solve the technical problems of microwave circuit test and fault diagnosis.The author explains embedded design of microwave circuit modules and approach of hardware design and software design，and finally verifies the embedded design of microwave circuit modules based on specific chips.
Keywords：Specific Chips；Microwave Circuit Modules；Embedded Test；BTT；Fault Injection
I.Introduction
At present，microwave circuit modules are widely applied in electronic equipment.For example，active phased array radar system has hundreds of T/R modules，at least，as core modules，and ten thousands at most.Each T/R module has tens of IC，which is typical microwave circuit module.
If there is no testability，it is difficult to find IC fault by peripheral test during the producing and debugging and it is also impossible to immediately or accurately judge the fault module and fault position.Therefore，embedded test and testable design of microwave circuit modules are urgent.
In foreign countries，testability is the key technical specification when US army order and design electronic equipment；testability design technology is adopted in research and production of foreign electronic equipments such as radar.However，people focus on testability design of digital circuit and analog circuit，testability design of microwave modules is seldom mentioned.
In China，microwave circuit modules have simple functional structure，and the fault is easy to judge.However，with the development of microwave monolithic integration hybrid integration，the functional structure of microwave circuit modules become more and more complicated，and it is impossible to judge fault without testability design which is the bottleneck for equipments’long-term running，producing，debugging and maintaining.Therefore，a method of embedded design verification test of microwave circuit modules based on specific chips is introduced to solve the technical problems of microwave circuit test and fault diagnosis and provide technical support for the fault location，fault dingoes，fault isolation and fault maintenance of RF and microwave subsystem of electronic equipment system.The maintaining expense is reduced and technical support efficiency is improved.
II.The Embedded Test Design of Microwave Circuit Modules The embedded design and testability design of microwave circuit should follow two principles.Firstly，the reliability of embedded test circuit is higher than that of tested microwave functional circuit，so we should carefully consider the reliability by using simple and mature circuit and reducing components during design of embedded test circuit.Secondly，if embedded test circuit has fault，microwave circuit modules should be ensured to work normally.Coupler instead of switch should be used in the interface of embedded test circuit and microwave modules.
The electronic subsystem is made of microwave circuit modules and the functional structure of microwave circuits are shown as follows：
According to Figure 1，microwave circuit modules（MCM） are mainly made of units of microwave components and microwave offset backplane.The former can realize the functions of filter，frequency division，mixing，amplification and attenuation；the latter is used in signal transmission，power conversion stabilization，BIT control and conditional information acquisition.Embedded test and testability design mean to set monitoring points in position of microwave components and previously make monitoring sensor circuit to monitor frequency，power and modulation waves of microwave circuit.According to sensor circuit，the power of microwave signals are divided，and these signals become analog signals with low frequency which can be transferred to unit of microwave offset backplane.Analog embedded chips and embedded controlling chips can deal with the analog signals，such as storage，fault indication and data uploading.The power and signals in DC operating points can also make condition monitoring and data acquisition by analog embedded chips and embedded controlling chips.The embedded controlling chips mainly control BIT of microwave modules.Besides，microwave embedded chips，analog embedded chips and embedded controlling chips are finally customized into specific chips，which are mounted in right position of microwave circuit modules to achieve the aim of embedded test design.
III.Embedded Test Design of Microwave Circuit Modules Based on Specific Chips
A.The design of the Hardware
The microwave modules with excellent embedded test and testability design can monitor and acquire the microwave parameter information of microwave functional circuit，such as，frequency，power and modulation waves.Secondly，they can monitor and acquire analog information of analog circuit of power supply and DC operating points.Thirdly，they have functions of power up BIT，cyclical BIT and initiating BIT of microwave circuit modules.Besides，they have functions of information storage，test information fusion and analysis；functions of fault diagnosis，isolation and location；function of information interaction by standard interface bus.Therefore，in the paper，the author designs the principle diagram of the embedded test and testability design of microwave modules.It is shown in Figure 2. In Figure 2，the microwave circuit modules are divided into yellow part and green part.The yellow part is unit of microwave components and the green part is that of microwave offset backplane.Embedded test and testability design of microwave modules exit in yellow part.Microwave embedded chips can be previously put into the right position of microwave component，and microwave signals are turned to analog signals with low frequency which is transferred into microwave offset backplane in green area.Analog signals with low frequency are previously disposed into the signals which are suitable to test analog chips，and then the signals are sent into analog embedded test chips by signal test channel and become digital analog signals.Once again，the signals are sent into embedded test chips to realize the fault isolation，location，conditional monitoring display，storage and uploading of microwave circuit.The power supply and DC operating points of microwave offset backplane can also realize fault isolation，location，conditional monitoring display，storage and uploading of analog circuit by preprocessing，analog chips and embedded control chips.Therefore，embedded test and testable design of microwave circuit modules should complete three kinds of design including testability design of microwave circuit unit，analog circuit unit and the design of embedded control chips.
Testability design of microwave circuit unit mainly refers to design circuit to realize power division of microwave signals，which can be changed into analog signals with low frequency to be output from microwave component unit.Specifically，microwave embedded chips turn microwave signals into analog signals with low frequency，and by using feed through capacitor these signals are transferred into microwave offset backplane unit to do follow-up processing.According to frequency，power and modulation waves of embedded microwave signals，the author designs three embedded chip circuit and makes them into specific chips to mount in the microwave circuit.
Testability design of analog circuit refers to design analog embedded chips to acquire or monitor node-information and condition of analog functional circuit in microwave offset backplane unit.Analog embedded chips will be customized into specific analog chips and different channels can be designed according to actual requirements of detection nodes.The author designs 32 channels and each channel has three instrumented functions of analog signal acquisition.They are Digitizer，digital voltmeter and frequency meter，and respectively realize embedded test of multi-channel analog signals such as wave forms，amplitude and frequency. The designers chose FPGA，Virtex-5 series in Xilinx to realize embedded control chips.The FPGA has embedded CPU hardcore POWERPC440，with fast arithmetic capability，high performance IO，flexible configuration.By protocol conversion，CPU can receive upper-computer commands and data information from back-plane bus.Depending on different information，CPU can load，unload，read or update programs and data，or operate BIT commands and other actions.Besides，FPGA definite registers，for example，command register，command decoder，state register，address register and data register，to register，decode CPU commands，and cache data of external memory.Peripheral circuit of CPU is mainly used to load FPGA program，storage operating system，applied software，database，table，fault records，memory，power supply and clock.The author develops IP based on FPGA and then customizes the specific chips when controller is debugged.
B.The design of the Software
1）Hierarchical Structure of software
The embedded test software in this paper is named as “E-BIT software”.E-BIT software is designed modules as hierarchical structure and is made of five layers from bottom to top.They are hardware，embedded operating system，BIT drive program，BIT applied program and BIT interface.The hierarchical structure is shown in Figure 3.
The hardware platform of E-BIT software uses PowerPC440 from Motorola as core processor.Peripheral equipment has a Flash Memory（M25P128）with 128Mbit which used to store starting code，Linux，user’s program，RS232 serial port，CAN bus interface and JTAG interface.
Embedded operating system lies in hardware and applied program and is responsible for task scheduling and real-time applied program management.Embedded operating system includes Boot loader，customized Linux operating system kernel and file system.It is a carrier providing good condition to manage configuration files and operate applied software.
Drive program include customized peripheral drive program and test-resource drive program.Because in Linux，all the equipment drivers can be statically connected and dynamically loaded，in order to improve CPU efficiency，peripheral drive program use static connection and test-resource drive program upload information dynamically according to running status.
Applied program have program sets，system management software，internal self-checking software，upgrading maintenance software，query information software and information processing software.BIT program sets include power embedded test program，cyclical embedded test program and initiating embedded test program. BIT interface is mainly used to operate general control software；communicate with upper computer；receive information commands and process them in real time；start applied programs by workflow.
2）BIT Test
BIT service can conduct embedded test of microwave circuit modules and read results.Embedded test include PBIT，CBIT and IBIT.By using microwave embedded chips，analog embedded chips and embedded control chips circuit，it can acquire frequency，power and modulation waves of microwave functional circuit and analog functional circuit.
3）Software Flow
The operating flow of E-BIT software is shown in Figure 4.
When microwave circuit modules are in normal working condition，general control software will run control interface and come into routine of receiving/sending message.These message commands come from interactive interface of general control software and internal/external communication bus of other softwares.General control will analyze message commands in time and classify them.Tasks have setting CBIT running status，running IBIT，internal self-checking software，upgrading maintenance software，query information software，system management software and information processing software.When general control software run the sub-modules software，they will not trace the running status.
General software will run CBIT cyclically in spare time.The running status of CBIT is done/ undone，or whether running interval can be changed in time or not.
IV.Embedded Design Verification Test of Microwave Circuit Modules Based on Specific Chips
In this paper，the author chooses digital signal processing modules and frequency-multiplication leveled amplifying modules of vector network analyzer as the verification object，which is called “instrument king” with the highest complexity and the most difficult technology.Using embedded specific chips，connecting software platform and diagnosis test program，the author roundly verifies the test information acquisition，transmission，diagnosis and diagnostic results in operating modes of PBIT，CBIT and IBIT.
Verification platform is made up of hardware and software.Hardware includes the vector network analyzer of digital signal processing module and frequency-multiplication leveled amplifying modules with excellent testability design.Besides，the instrument has embedded diagnosis computer.The verification platform is shown is Figure 5.
Verification platform software are the developed software platform and test diagnostic program.The main surface and subsurface of software platform are shown as follows：shown in Figure 6. Instruments required in verification are listed as follows：
From test verification and test results，embedded design verification test of microwave circuit modules get good effect in vector network analyzer.Running status of each test node can be directly observed in verification interface and light-sound alarm system will be operated if there is fault.The acquisition data are consistent with actual test data，which can prove that the embedded test chips have satisfied requirement of performance index and have good stability.In addition，data query，data browse and run-chart analysis can be done by embedded test software to analyze test information and get diagnostic results.Therefore，the embedded design verification test based on specific chips has some feasibility.
V.conclusion
In the paper，embedded specific chips with small size，little weight and low consumption，can not only reduce the space taken up by embedded test circuit in functional circuit board，but can also improve the stability of embedded circuit in microwave circuit modules and solve the technical problems of microwave circuit test and fault diagnosis.
References
[1]Mohrenschildt M V.Hybrid Systems:Solutions,Stability,Control.Proceedings of the 2000 American Control Conference,2000,1:692-698.
[2]Lafferriere G,Paas G J,Sastry S.Reachability Analysis of Hybrid Systems Using Bisimulations.Proceedings of the 37th IEEE Conference on Decision and Control,1998,2:1623-1628.
[3]Kmenta S,Ishii K.Scenario-Based FMEA:A Life Cycle Cost Perspective.ASME DETC,2000.
[4]Chang C L,Liu P H,Wei C C.Failure Mode and Effects Analysis Using Grey Theory.Integrated Manufacturing Systems,2001,12(3):211-216.
[5]Oakland S F.Considerations for Implementing IEEE 1149.1 on System-On-A-Chip Integrated Circuits.International Test Conference,2000:628-637.
作者简介：郭荣斌（1971—），男，高级工程师，中国电子科技集团公司第41研究所室主任，主要从事电子测试仪器方面的研发和部门的管理工作。