Patent Application
20080079439
A system embodying the invention includes self-contained embedded diagnostics for a piece of electronic equipment. Among other fields, such a system may be employed in a measurement apparatus for radiofrequency (hereinafter “RF”) systems.
In such systems, it is desirable to be able to self-diagnose problems which can be solved by replacing sub-assemblies, cables, etc., without requiring the use of external test and measurement equipment. When such a problem is diagnosed, service personnel not necessarily requiring great expertise or training, can replace the problem component.
In the discussion which follows, the term “indicted” will be used to describe a component, sub-assembly, etc., for which a problem has been diagnosed. Also, the terms “component” and “communication component” will be used interchangeably, to refer broadly and without limitation to any sub-assembly, cable, interface, component, etc., within a piece of equipment, for which a fault may occur. The term “fault” will refer to any problem that is, or can be, isolated within a particular component of the piece of equipment.
A diagnostic performed by a system embodying the invention can identify an indicted component, a failing component, or the component most likely to fail or to have failed. Also, the particular nature of the fault or failure can be identified.
In operation, a test signal is injected into the communication pathway. The test signal may be generated by the test controller 10 or by an outside signal source (not shown). The signal may be injected at a test point such as one of the test points 14, 16, 18, and 20, or at an input point or starting point (not shown) of the communication pathway 2.
For a given input test signal, it is possible to predict what signal should be present at a given one of the test points. It is also possible to determine, for a test point signal different from that which should be present, whether a nearby component is failing, and what the nature of the fault is.
Therefore, the test controller 10 can monitor the signals at the test points 14, 16, 18, and 20, and use those signals to identify faulty components. For instance, if signals at the test points 14 and 16 are normal, but a signal at the test point 18 is abnormal, this might indicate a fault in the component 6. Also, if the signal at the test point 18 is, for instance, stuck in an idle state instead of showing signal traffic, it might indicate that a circuit element in the component 6 such as a transistor amplifier might have failed, or a cable connector might have a broken wire.
In such a system, a problem diagnosis can be completely self-contained, and require no external measurement equipment. Where a failed hardware component is identified, an operator or technician can replace a failed component (a cable, sub-assembly, etc.), with a high confidence level that the replacement will successfully repair the equipment. Since the most likely failing sub-component is identified on the indicted parent sub-assembly then the task of fault finding to component level is significantly reduced.
Once a faulty component is identified, it may also be desirable to perform a more detailed diagnosis to identify and fix a particular failing sub-component, sub-assembly, etc., within the component. Such more detailed diagnosis can be performed either while the component is still within the equipment, or performed separately after it has been extracted and replaced. Such additional more detailed diagnosis may need more specific models, testing, test equipment, etc.
Test results can be accumulated for purposes such as statistical analysis. In one embodiment, failure information, information on indicted sub-assemblies, etc., is stored in a failure history record store, such as an electrically alterable programmable read-only memory (EEPROM) apparatus.
The embedded diagnostic can be executed remotely, responsive to a remote command received over a communication network coupled to the equipment.
The LO (Local Oscillator) provides the signal that is used in the down conversion of the RF signal to an IF (intermediate frequency) signal in much the same way a SuperHetrodyne radio receiver works. To avoid mixer image frequencies and to get from GHz frequencies down to a baseband frequency range (MHz) that can be digitally processed, the illustrated analyzer uses 2 or 3 conversion stages. The final IF is the intermediate frequency stage that can be processed by an embedded diagnostic measurement system embodying the present invention.
Normally, employing embedded diagnostics onto RF measurement systems would present a few issues.
These two issues present a problem for embedded RF diagnostics. If one of these long RF paths has a component which is so faulty that no signal reaches the Final IF, then there is no way to know where the signal went bad.
Typically the test engineer would half split a problem like this. They would try to find a signal half way along the measurement path. If the signal was good, then they know that the bad component lies in the latter half of the measurement path. If the signal is bad, then they know the failing component (assuming there is only one) is in the first half of the RF path. Once the test engineer has established within which half of the signal path the signal has been impaired, he/she will now half split the problem again across that half, and repeat this technique until the fault has been narrowed down and localized, and is isolated.
Detectors, as shown schematically in
Parallel topology also helps mitigate RF issues in these long measurement paths. In the instrument of
Responsive to the test command, the test controller sends (54) a test signal through the communication pathway. The test controller then monitors the various test points along the communication pathway, to detect and obtain test information (56) regarding how the various components of the equipment, along the communication pathway, are behaving. The detected test information is analyzed (58) to determine whether the components are functioning normally, or whether an abnormality that may be indicative of a fault or problem has been detected.
Based on that analysis, it is determined (60) first, whether a fault has been detected, and second, based on which test points show which abnormalities, which component seems to be faulty. If no fault is detected, the test apparatus idles or performs other functions until another test command (52) is received.
If a fault is detected, the faulty component, and the nature of the fault, are analyzed (62) and reported to the system operator (64), through a user interface, printer, display, etc. The report is in a form that will direct the operator to replace the component believed to be faulty. Where an operator does not necessarily have great expertise with the equipment but has facility with swapping components in and out, the report is sufficient to enable the operator to take action that will enable the equipment to keep on functioning.
The form and content of the report can be analogized to an incident in Arthur C. Clarke's science fiction novel 2001: A Space Odyssey. The HAL 9000 computer on board the spacecraft Discovery directed astronaut David Bowman to replace the AE-35 unit, which was reported to be faulty and, if it were to fail, would have disabled the communication link to Earth. Astronaut Bowman then performed an extravehicular activity to replace the AE-35 unit.
Although the present invention has been described in detail with reference to particular embodiments, persons possessing ordinary skill in the art to which this invention pertains will appreciate that various modifications and enhancements may be made without departing from the spirit and scope of the claims that follow.
