Abstract:
Methods and devices for coordinating and displaying electronic signals are disclosed. For example, an exemplary apparatus configured a particular system can include a local timing device capable of receiving external real-time clock signals from a first time source, the timing device being capable of maintaining a synchronized local real-time clock based on the received external real-time clock signals, instrumentation configured to detect and capture one or more local signals, an operator interface having at least a first display window capable of displaying an image of the one or more local signals, and a marking device coupled to the operator interface and configured to enable an operator to manually align one or more local markers to specific points relative to the displayed local signal image, wherein the marking device is further configured to derive a marking time for each local marker using the local real-time clock, wherein the marking device is further configured to receive remote marking information from a remote device, and wherein the apparatus is configured to provide at least one of the remote marking information and data derived from the remote marking information to the operator via the display window.

Description:
BACKGROUND  
       [0001]     Modern oscilloscopes often have what is known as a “marker” function, which can be useful for a number of things, such as giving a precise indication of an interval between two items of interest on an oscilloscope display. For example, often an electrical signal will consist of a “burst” of pulses, and an engineer examining the pulses will desire to know the duration of each pulse as well as the duration of the entire burst of pulses. By using the appropriate oscilloscope controls, the engineer can evoke two markers, align the first marker with the start of a particular pulse and align the second marker with the end of the pulse. As the engineer adjusts the alignment of the second marker, the oscilloscope can automatically display the time difference between the two pulses until both markers are appropriately set and the difference of time can be noted. Time measurement of the entire burst can be similarly made.  
         [0002]     Unfortunately, this process has its limits, especially when an operator desires to precisely determine the time difference between two signals that are separated by large distances. This is due to the inherent limitations as to the lengths of oscilloscope probes (typically being no more that a few meters), as well as the problem of synchronizing different oscilloscopes given that the necessary synchronization technology is still in its infancy. Accordingly, new technology related to the capture and display of analog and digital signals is desirable.  
       SUMMARY  
       [0003]     In a first embodiment, an apparatus configured to monitor and/or test one or more devices or systems includes a local timing device capable of receiving external real-time clock signals from a first time source, the timing device being capable of maintaining a synchronized local real-time clock based on the received external real-time clock signals, instrumentation configured to detect and capture one or more local signals from a local tested device, wherein the one or more local signals start at a first time and have a first duration, an operator interface coupled to the instrumentation having at least a first display window capable of displaying an image of the one or more local signals, and a marking device coupled to the operator interface and configured to enable an operator to manually align one or more local markers to specific points relative to the displayed local signal image using the display window, wherein the marking device is further configured to derive a marking time for each local marker using the local real-time clock, wherein the marking device is further configured to receive remote marking information from a remote device, the remote device having its own separate instrumentation and its own marking device capable of deriving a marking time for a number of remote markers using a remote real-time clock also synchronized to the first time source such that the local real-time clock and the remote real-time clock are synchronized to an appreciable precision, and wherein the apparatus is configured to provide at least one of the remote marking information and data derived from the remote marking information to the operator via the display window.  
         [0004]     In a second embodiment, an apparatus configured to monitor and/or test one or more devices or systems includes a marking means for generating local marking information for a locally measured signal, the marking means also for receiving remote marking information derived from a remote device, wherein the local marking information includes data indicating a first locally-generated marker and local time information indicating a locally derived time for the first locally-generated marker, wherein the remote marking information includes data indicating a first remotely-generated marker and remote time information indicating a remote derived time for the first remotely-generated marker, and wherein the local time information and the remote time information are derived from separate respective synchronized time clocks, and a display capable of displaying a graphic representation of the locally measured signal as well as an indication as to the time difference of the local and remote markers.  
         [0005]     In a third embodiment, a method for monitoring and/or testing a first system using a set of distinct and independent electronic instruments with each instrument monitoring a different portion of the first system includes synchronizing a local real-time clock residing in a local instrument and a remote real-time clock residing in a remote instrument using a common network, the local and remote instruments being part of the set of distinct and independent electronic instruments, monitoring a first local signal generated by the first system by the local electronic instrument, generating a first local time marker related to the first local signal by an operator using the local electronic instrument, receiving, by the local electronic instrument and from the remote electronic instrument, a first remote time marker related to a first remote signal, and displaying a time difference indication of the first local marker and the first remote marker using a dedicated display incorporated into the local electronic instrument. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0006]     The example embodiments are best understood from the following detailed description when read with the accompanying drawing figures. It is emphasized that the various features are not necessarily drawn to scale. In fact, the dimensions may be arbitrarily increased or decreased for clarity of discussion. Wherever applicable and practical, like reference numerals refer to like elements.  
         [0007]      FIG. 1  depicts a communications network in concert with an exemplary real-time testing system;  
         [0008]      FIG. 2  depicts a block diagram of an exemplary test instrument;  
         [0009]      FIG. 3  is a first exemplary display screen with embedded controls useful for generating local markers and importing remote markers;  
         [0010]      FIG. 4  is a second exemplary display screen with embedded controls useful for capturing and manipulating local and remote time markers;  
         [0011]      FIG. 5  depicts the second exemplary display screen of  FIG. 4  modified to display remotely capture waveforms as well as remote time markers;  
         [0012]      FIG. 6  depicts the exemplary display screen of  FIG. 5  manipulated to show independent amplitude and time scaling between remotely and locally captured data;  
         [0013]      FIG. 7  depicts the exemplary display screen of  FIG. 5  further manipulated to show independent amplitude and time scaling between multiple remotely and locally captured data;  
         [0014]      FIG. 8  depicts the exemplary display screen of  FIG. 5  further manipulated to show independent amplitude and time scaling between one remote and multiple locally captured data; and  
         [0015]      FIG. 9  is a block diagram outlining various exemplary operations directed to the generation and display of local time markers as well as the generation, importation and display of remote time markers. 
     
    
     DETAILED DESCRIPTION  
       [0016]     In the following detailed description, for purposes of explanation and not limitation, example embodiments disclosing specific details are set forth in order to provide a thorough understanding of an embodiment according to the present teachings. However, it will be apparent to one having ordinary skill in the art having had the benefit of the present disclosure that other embodiments according to the present teachings that depart from the specific details disclosed herein remain within the scope of the appended claims. Moreover, descriptions of well-known apparatus and methods may be omitted so as to not obscure the description of the example embodiments. Such methods and apparatus are clearly within the scope of the present teachings.  
         [0017]     For the purposes of clarity and simplicity, the following disclosure is generally directed to systems employing oscilloscopes. However, as will be apparent to one of ordinary skill in the art while reading the following disclosure, the concepts discussed below can be equally applied to other test and measurement devices, such as logic analyzers, logic probes, spectrum analyzers, instruments directed to time-domain reflectrometry, remote data sensors, data bus analyzers, various specialty equipment and so on.  
         [0018]      FIG. 1  depicts an exemplary testing system  100  used in concert with a tested system  101 , which for the present example is a communication system having a signal source  140  and signal destination  160  with some intermediate transmission media  150  having an inherent impulse response h[t] and delay t TAU . The exemplary testing system  100  consists of two instruments  120  (e.g., oscilloscopes) and a precision time source  130  coupled to a common network  110  via links  112 .  
         [0019]     In operation, the instruments  120  can be first synchronized to time source  130  such that each instrument  120  will have an internal timing device/clock that reflects (within an appreciable amount of precision) the same time as the time source  130 . An example of such a synchronization technology can be found in the IEEE 1588 standard for “A Precision Clock Synchronization Protocol for Networked Measurement and Control Systems” (2002). However, the particular approach used for clock synchronization between various remotely-placed instruments can change from embodiment to embodiment without departing from the spirit and scope of the disclosed methods and systems.  
         [0020]     As discussed above, the exemplary instruments  120  are digital oscilloscopes having a number of known/conventional functions, such as the ability to capture and display various analog and digital signals. Additional conventional function of the exemplary oscilloscopes can include the placement of markers relative to various displayed waveform features (e.g., the rising and falling edges of pulses), which can also automatically provide some form of numeric display indicating the time difference(s) between various markers.  
         [0021]     However, in contrast to a typically/conventional oscilloscope, an oscilloscope of the present disclosure can associate each marker that an operator evokes with an “absolute time” reference using its internal synchronized time clock. Each absolute time reference, in turn, can be used to produce time difference values between markers.  
         [0022]     In addition to the generation and placement of time markers, the oscilloscopes of the present disclosure can also import and/or export information about various markers generated using remotely place oscilloscopes. Such information can include some form of ID (e.g., a network address coupled with a marker number) as well as a respective synchronized absolute time value. Assuming that a particular exported marker is imported by a synchronized oscilloscope, the exported/imported marker can be compared to locally produced markers to produce meaningful information.  
         [0023]     For example, an operator using a first exemplary oscilloscope can import a particular marker (with respective synchronized time value) derived using a second exemplary oscilloscope 50 yards away using an IEEE1588-compatible Ethernet communication system. Similarly, the same operator could import another particular marker (with respective synchronized time value) derived from yet another oscilloscope 50 miles away via the internet and using another synchronization technology. Once the various markers are imported, the imported markers can be referenced and their values displayed. Additionally, the differences between various locally derived markers and various imported markers can also be displayed and meaningfully interpreted/reviewed as the differences would be accurate to an appreciable precision. Other information, such as “screen shots” of oscilloscope waveforms, especially screen shots for which imported markers are correlated, can also optionally be imported and displayed.  
         [0024]     In various embodiments, it should be appreciated that there can be circumstances where using separate operators to manipulate each oscilloscope/instrument may be problematic. Accordingly, in various embodiments the exemplary instruments can be specially configured such that a single operator using a display and/or controls of a single exemplary instrument can remotely perform data capture functions, such as adjusting the gain and timescale of a remote oscilloscope, adjusting the oscilloscope&#39;s triggering, evoking and setting remote markers, and so on. Additional useful operations can further include the importation of remotely captured waveforms as well as the importation of marker information.  
         [0025]     The exemplary network  110  is an IEEE 1588-compliant Ethernet-based network. However, in other embodiments the network  110  can be any viable combination of devices and systems capable of linking computer-based systems including a wide area network, a local area network, a connection over an intranet or extranet, a connection over any number of distributed processing networks or systems, a virtual private network, the Internet, a private network, a public network, a value-added network, an intranet, an extranet, an Ethernet-based system, a Token Ring, a Fiber Distributed Datalink Interface (FDDI), an Asynchronous Transfer Mode (ATM) based system, a telephony-based system including T1 and E1 devices, a wired system, an optical system, a wireless system and so on.  
         [0026]     The various links  112  of the present embodiment are a combination of devices and software/firmware configured to couple computer-based systems to an IEEE 1588-compliant Ethernet-based network. However, it should be appreciated that, in differing embodiments, the links  112  can take the forms of Ethernet links, modems, networks interface card, serial buses, parallel busses, WAN or LAN interfaces, wireless or optical interfaces and the like as may be desired or otherwise dictated by design choice.  
         [0027]      FIG. 2  depicts a block diagram of an exemplary test instrument  120 , such as the test instruments discussed with respect to  FIG. 1 . As shown in  FIG. 2 , the test instrument  120  includes a controller  210 , a memory  220 , a timing device  230 , a collection of instrumentation  240  containing a data capture device  242  and triggering device  244 , a marking device  250 , an operator interface  260  and an input/output device  290  capable of communicating with any number of networks. The marking device  250  contains a marker ID field  252  and a time field  254  to store information relating to each specific marker evoked by an operator.  
         [0028]     Although the exemplary instrument  120  of  FIG. 2  uses a bussed architecture, it should be appreciated that any other architecture may be used as is well known to those of ordinary skill in the art. For example, in various embodiments, the various components  210 - 290  can take the form of separate electronic components coupled together via a series of separate busses or a collection of dedicated logic arranged in a highly specialized architecture.  
         [0029]     It also should be appreciated that some of the above-listed components can take the form of software/firmware routines residing in memory  220  and be capable of being executed by the controller  210 , or even software/firmware routines residing in separate memories in separate servers/computers being executed by different controllers.  
         [0030]     Returning to  FIG. 2 , operation starts as the instrument  120  is synchronized such that the timing device  230  contains a real-time clock that is synchronized to an external time source, such as a precision real-time clock specifically configured to provide a common time-base for a variety of different instruments. Synchronization with an external time source optionally can be established via the input/output device  290  and an external network, but the particular form of synchronization approach used can change from embodiment to embodiment as may be found advantageous.  
         [0031]     Once the timing device  230  has established a synchronized real-time clock, an operator using the operator interface  260  can monitor any number of electronic signals by commanding the instrumentation  240  to capture various waveforms using the trigging device  242  and data capture device  244 . Next, the captured waveforms can be displayed at the operator interface  260 . Then, using the marking device  250  and timing device  230 , the operator can evoke various markers and appropriately align the markers using graphic cues available at the operator interface  260 . Marker information, e.g., an ID and respective absolute time reference, can be internally stored in the appropriate marker fields  252  and  254 .  
         [0032]      FIG. 3  depicts a first exemplary operator interface  260  (or a portion thereof) having a display screen  310  with embedded controls, including controls for capturing local signals (not shown for simplicity), a first set of virtual instruments  320  for evoking local time markers and a second set of virtual instruments  330  for importing remote time markers. Local markers can be evoked and manipulated using the “ADD”, “SELECT” and “REMOVE” buttons as well as the left/right arrows  326 . Remote markers, which for the present example are derived independently of the operator interface  260 , can be evoked by merely pressing either of the “REMOTE R 1 ” or “REMOTE R 2 ” button.  
         [0033]     As shown on  FIG. 3  an exemplary pulse waveform  312  is displayed based on a first amplitude scale A L1  and first timebase T L1 . The pulse  312  is shown as coming from “channel A” of a local oscilloscope (which often have two channels referred to as “A” and “B”). Local markers L 1  and L 2  are depicted as superimposed on the rising and falling edges of the pulse  312  with a relative time difference T A  being displayed in graphic form between L 1  and L 2 . Absolute time is also available as a simple displayed value for each of L 1  and L 2 .  
         [0034]     In the present embodiment, remote marker R 1 , which is presumably derived by a remote operator using a remote oscilloscope, is not displayed graphically but only in terms of a numeric, absolute time value. Remote marker R 2  is depicted as being disabled/not used. Absolute time for marker R 2  and the relative times between the local markers L 1  and L 2  and remote marker R 1  are also provided.  
         [0035]     Returning to  FIG. 2 , in addition to importing remote marking information, the exemplary instrument  120  can also export marking information residing in the marking device  260  based upon commands received either remotely or via the operator interface  260 . That is, the exemplary instrument  120  can play the role of a remote device to another instrument.  
         [0036]     In still yet other embodiments, a particular instrument can be configured to manipulate remote marker information, as oppose to merely import remotely derived markers. For example,  FIG. 4 , which shows the operator interface  260  of  FIG. 3  modified to include a series of remote marker controls  440 , can be used to enable an operator to take control of a remotely located instrument identified by the “REMOTE ADDRESS” field by pressing the “REMOTE ACCESS” button. Once in control, the operator can evoke and manipulate remote markers using the “ADD”, “SELECT” and “REMOVE” buttons as well as the left/right arrows  446 , with each marker being automatically imported for local display.  
         [0037]      FIG. 5  shows yet another embodiment of the operator interface  260  of  FIG. 2  where the display  310  is split into two portions:  310 A and  310 B. As shown in  FIG. 5 , locally derived information is displayed in display portion  310 A and remotely derived information is displayed in display portion  310 B.  
         [0038]     For the purpose of the present example, local information is presumed to precede remote information, and so display portion  31  OA is ergonomically placed to the left of display portion  310 B to resemble a conventional timeline. Display portion  310 A is depicted as having a (optionally adjustable) time discontinuity of T D1  with respect to display portion  310 B. Note that a left/right format can provide a better sense of time sequence than the typical up/down display of conventional oscilloscopes. While local information is depicted on the left and remote information on the right, it should be appreciated that, should remote information precede local information, such remote information can automatically be place to the left of the local information. Additionally, let/right sequence can alternatively be changed should the operator desire to intentionally make such a display change.  
         [0039]     For the present example of  FIG. 5 , the necessary controls to manipulate remote amplitude A R1 , remote timebase T R1  and remote triggering are omitted for simplicity of display. Also note that remote and local amplitude and timebase information can be independently manipulated and displayed for the benefit of the operator. To further demonstrate this point,  FIG. 6  is provided, which depicts a variation of the display of  FIG. 5  where the timescale and amplitude of the remote display portion  310 B have been changed independent of the timescale and amplitude of the local display portion  310 A.  
         [0040]      FIG. 7  depicts another variation of the display of  FIG. 5  where the timescale and amplitude of the remote display portion  310 A have been changed without affecting the waveform of display portion  310 B, and a third display portion  310 C is added to depict remotely captured waveforms and markers from a second remote instrument. As with the other display portions  310 A and  310 B, the amplitude A Z1  and timescale T Z1  attributes of display portion  310 C can be independently set. Similarly, time discontinuity values T D3  and T D4  can be independently set in the same manner as the time discontinuity value T D1  of  FIG. 5 .  
         [0041]      FIG. 8  depicts yet another variation of the display of  FIG. 5  where the third display portion  310 C is used to display a locally captured waveform (via channel B) of the same oscilloscope used to capture the waveform used for display portion  310 A.  FIG. 8  is used to demonstrate that the use and placement of display waveforms and marker data can vary in a versatile manner. That is, while the local waveforms  312  and  317  of display portions  310 A and  310 C are depicted as coming from two different A/B channels of the same oscilloscope, it should be appreciated that the same amplitude and timescale display versatility discussed using different oscilloscopes can be applied to the same oscilloscope. Still further, it should be appreciated that the same amplitude and timescale display versatility discussed using different oscilloscopes can be applied to the same channel of the same oscilloscope. That is, the present display portions  310 A- 310 C can be used to display different portions of the same signal (with different amplitude and timebase scaling) derived from the same electrical node, but differing substantially in time.  
         [0042]      FIG. 9  is a block diagram outlining various exemplary operations directed to the capture and display of local and remotely captured data. The process starts in step  902  where a number of test instruments at various locations remote with respect to one another are set up. That is, each instrument is connected to nodes of interest, appropriately powered, appropriately connected to a network and so on. Next, in step  904 , the test instruments of step  902  are synchronized using any of various known or later developed techniques. Then, in step  906 , the various systems to be tested are put into whatever mode of use is to be tested. Control continues to step  908 .  
         [0043]     In step  908 , various time markers at each instrument are manipulated and set. As discussed above, such markers can be set locally by independent operators, or alternatively set by a single operator using locally available controls that can be embedded into an instrument or into a separate computer-based device. Next, in step  910 , a particular operator at a particular instrument can identify and import marking information of interest, or in contrast a particular operator at a particular instrument can export marking information of interest to an identified instrument. Control continues to step  912 .  
         [0044]     In step  912 , local and remote marking information, including some form of ID and respective absolute time, can be displayed. Similarly, time differences between various markers, including between local and remote markers or between different remote markers derived from different remote instruments, also can be displayed. Control continues to step  914 .  
         [0045]     In step  914 , various local and remote channels of interest can be identified. For example, an operator at a first oscilloscope can identify: (1) a local oscilloscope channel, and (2) a set of data lines monitored by a remotely located logic analyzer. Control continues to step  916 .  
         [0046]     In step  916 , the desired local and remote data can be collected, which can involve certain data collection steps, such as setting triggers, setting allowable time windows or setting any other of the various known data collection prerequisites, as well as the actual export, transfer and reception of data. Control continues to step  918 .  
         [0047]     In step  918 , a display mode for the data identified in step  914  is determined, which for the present circumstances can take a variety of forms, including those left/right formats discussed above. It can also include accounting for different amplitude scales, timebases, time discontinuity values, location of comments and text, sequence of waveforms and so on. Next, in step  920 , the collected data is appropriately formatted and displayed according to the display modes of step  918 . Control then continues to step  950  where the process stops.  
         [0048]     In various embodiments where the above-described systems and/or methods are implemented using a programmable device, such as a computer-based system or programmable logic, it should be appreciated that the above-described systems and methods can be implemented using any of various known or later developed programming languages, such as “C”, “C++”, “FORTRAN”, Pascal”, “VHDL” and the like.  
         [0049]     Accordingly, various storage media, such as magnetic computer disks, optical disks, electronic memories and the like, can be prepared that can contain information that can direct a device, such as a computer, to implement the above-described systems and/or methods. Once an appropriate device has access to the information and programs contained on the storage media, the storage media can provide the information and programs to the device, thus enabling the device to perform the above-described systems and/or methods.  
         [0050]     For example, if a computer disk containing appropriate materials, such as a source file, an object file, an executable file or the like, were provided to a computer, the computer could receive the information, appropriately configure itself and perform the functions of the various systems and methods outlined in the diagrams and flowcharts above to implement the various functions. That is, the computer could receive various portions of information from the disk relating to different elements of the above-described systems and/or methods, implement the individual systems and/or methods and coordinate the functions of the individual systems and/or methods described above.  
         [0051]     The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.