Network test instrument with testing session analysis

A test instrument can be coupled to a test point in a network and measure signals in the network that are received via a port connected to the test point. The test instrument may connect to the network via multiple test points. The measurements of the signals received through one or more of the test points are correlated to detect a problem in the network and determine a suggested action.

BACKGROUND

Service provider networks typically delivers services, such as digital television, high-speed Internet, Voice-over-IP (VoIP), etc., to customer premises. Also, the networks typically carry bi-directional traffic. For example, a typical cable network is a two-way hybrid fiber-coaxial (HFC) network that supports point-to-multipoint transmission in the downstream direction using digital signals or a mix of analog and digital signals, and multipoint-to-point transmission in the upstream direction. Downstream signals, which carry broadcast digital TV signals, Internet traffic, etc., are distributed via a fiber optic connection from a head-end to a node that converts the optical signals to electrical signals and then distributes the signals to customer premises via a tree and branch coaxial cable distribution network termed ‘cable plant’. Recently, service providers are running fiber to the customer premises to improve bandwidth. At the customer premises, terminal equipment supports the delivery of services, which may include video, data and voice services, to customers for example via cable modems. Upstream signals from the customer premises may carry phone and Internet traffic. The upstream signals propagate from the branches of the cable plant towards the headend of the network.

The upstream and downstream signals are prone to impairments originating at various locations in the network. There may be numerous devices, cable segments and connectors located between the fiber optic node and the customer premises equipment where defects can occur, and defects and impairments can occur at different customer premises that can impact the signal quality of other customer premises. Tracing a source of an impairment typically requires that a technician travels to different network locations and takes signal measurements to locate the sources of the impairments. Portable network testing devices currently used in the industry may help to identify certain types of defects by performing various signal measurements, such as spectral and noise measurements.

DETAILED DESCRIPTION

A test instrument for networks can be connected to a network to measure parameters or characteristics of signals transmitted in the network. A test instrument for example is an apparatus that can connect to a network to receive signals transmitted in the network and measure characteristics of the signals. The test instrument may include a single port or multiple ports to connect to a single cable of the network or to simultaneously connect to multiple cables of the network to take measurements. The test instrument may be a handheld portable device or a larger device. The test instrument is also referred to as a network signal testing device.

The test instrument may be connected at various test points in the network to take signal measurements at each location, and multiple test points may be for the same customer premises. For each test point, testing includes measuring characteristics of signals received by the test instrument connected at the test point. Some examples of signal measurements performed by the test instrument may include spectral and noise measurements. The test instrument may use Frequency-Domain Reflectometry (FDR) and/or Time-Domain Reflectometry (TDR) to measure reflections, i.e., reflected signals. Reflectometry pulses (e.g., TDR or FDR pulses) may be generated and output via a port of the test instrument, and characteristics of the reflected signals, such as amplitude and reflection time, i.e., the time it takes for the pulse to return to the port, are measured to determine signal signatures, detect locations of impairments, etc. Signal levels are measured and displayed for example to verify proper levels arriving at the test point. Frequency response is measured for example to verify proper losses and to uncover any roll-off or sharp changes in response. Other characteristics may be measured as is further described below.

According to examples of the present disclosure, the test instrument can perform automated measurements in the background and correlate the measurements to detect a problem in the network and a suggested action. The measurements may be taken at multiple test points and the measurements from one or more of the test points can be correlated to detect a problem and suggested action. The suggested action may be to remedy the problem or to further verify or identify the problem. The test instrument for example includes a display, and the test instrument can display a description of problems that were identified based on correlated measurements and their suggested actions to solve the problems.

In an example, the test instrument can be used to measure signals in cable television systems, and the test points where the measurements are taken may include a tap which connects to the plant distribution network, a drop which is a cable going from the tap to the customer premises and which can be aerial or buried, a ground block which is a typical demarcation point that may be located on the side of the customer premises, and at the customer premises, such as to the end user outlet or Consumer Premise Equipment (CPE). These and/or other test points may be tested during a service installation or for troubleshooting a service ticket. A session for example is a set of tests performed for a specific job, work order, or service ticket. A user of the test instrument may initiate a new session for each job or work order. The job or work order identifier (ID), also referred to as a session ID, can be manually entered, automatically derived from a workforce management system, derived from a geographic location which may be determined from a Global Positioning System (GPS), derived from a time stamp, derived from a bar code scanned or other methods. The unique session ID is used to save measurements for a session, and to analyze and provide user feedback based on the tests taken at multiple locations for the session. The correlation of measurements to determine problems and suggested actions for the session may be performed by a processing circuit (e.g., processor) at the test instrument or by a remote computer which may be a cloud server or both locally and remotely.

The test instrument may include a processor, display, and data storage to store and display measurements and notifications, and to store signatures and other information and to correlate measurements for problem detection. The test instrument may include a communications interface, such as WiFi, Bluetooth, Ethernet, cellular, etc., to connect the test instrument to other devices via a network, and to transmit the stored data to other devices or computers. In one example, the test instrument is a portable, hand-held device that may connect to the cloud or any remote computer via the network interface. In other examples, the test instrument may be part of a larger system. The test instrument may be used to measure signals in any suitable type network, include cable television networks, optical networks, in-home wiring, etc.

FIG. 1illustrates a test instrument100connected to a network101according to an example of the present disclosure. In this example, the network101is a cable TV network but the test instrument100may be used in other types of networks. Network101shown inFIG. 1may be a local portion of a hybrid fiber coaxial (HFC) network that delivers Cable Television (CATV) signals, including digital TV signals and data and control signals, to end users at customer premises53.

A fiber-optic node10of the cable network101for example includes a downstream (DS) optoelectronic converter10A that converts downstream (DS) optical signals generated by a remote Cable Modem Termination System (CMTS) (not shown) into downstream electrical RF signals11, and an upstream (US) electro-optic converter10B that converts upstream (US) electrical RF signals13into US optical signals for upstream transmission to the remote CMTS. The fiber-optic node10is coupled via a coaxial cable12to a bidirectional amplifier15, which amplifies the downstream RF signals11for distribution to first and second groups of customer premises53A and50B. The downstream RF signals11generated by the downstream optoelectronic converter10A of the fiber node10are distributed to a plurality of end-of-the-line subscribers, or end users for example via one or more trunk coaxial cables44and subscriber taps51. At the customer premises53, the DS signals are demodulated using cable modems (not shown). One or more two-way trunk RF amplifiers40may further be provided in each trunk cable44to suitably amplify the upstream and downstream CATV signals on their way to and from the customer premises53. The first and second groups of customer premises50A and50B may send upstream signals31A and31B, respectively, which may be combined by the bidirectional amplifier110into the upstream RF signal13propagating towards the fiber node106for delivering to the remote CMTS at the headend (not shown). The cable network101may serve a large number of customer premises, which may be connected by taps51to a plurality of different cable trunks44at a plurality of different locations. The trunk cables44may be buried in the ground or they may be elevated above the ground on utility poles, or a combination of both. In other examples, fiber cables may be run to the home and the test instrument100may connect to the fiber cables.

The test instrument100may be connected to the cable network101at a desired test point to test signals (upstream and/or downstream) passing through the test point. The test instrument100is shown as connected at test point105. The test instrument100may be connected at any location where connections are available to connect to the network101. For example, the test instrument100is connected to the network101via a test access point (tap) to measure signals flowing through the tap. The tap for example is a 3 port hardware device and one port is monitor port connectable to the test instrument100to measure signals in the network passing through the tap. The tap may provide more than test point access. For example, the tap may be a hardware device that ‘taps” off the line and feeds one or more customer premises and is where the test instrument100can be connected.

The test instrument100may include one or more ports to connect to the test point105. In an example, the port(s) include coaxial RF cable connectors. It will be appreciated that test instrument100may also have other non-cable ports, for example to connect to a computer or to an external display, such as but not exclusively one or more USB ports and the like.

The test instrument100is inserted for example by coupling a port of the test instrument100to a cable in the network101. In this manner, signals in the network are received at the test instrument100. The test instrument100for example may include a dual port test instrument. For example, one port may be connected downstream such as toward a customer premises, and one port may be connected upstream towards a network node. Signals (e.g., upstream or downstream) in the network may flow through the test instrument100and may be measured. In another example, the test instrument100may be a single port device. For example, the test instrument100is connected to the network101via a tap to measure signals flowing through the tap at the test point105. The tap for example is a 3 port hardware device and one port is monitor port connectable to the test instrument100to measure signals in the network passing through the tap. A dual port test instrument may also be connected to a tap.

FIGS. 2A-Bshow examples of connecting the test instrument100at different test points.FIG. 2Ashows the test instrument100connected to a tap250ain a portion of the network101between amplifier40aand customer premises53a. There may be multiple taps250a-nand the values (e.g., 26, 23, 20 . . . ) shown for the taps250a-nare examples of tap values, e.g., attenuation measured at the tap, in decibels. The downstream signal is significantly attenuated by the time it reaches the endpoint, which may be a customer premises. A customer premises may also be connected via a drop line, also referred to as a trunk line, at each tap. Drop line220is shown connected to the customer premises53a. The test instrument100in this example is dual port device with ports 1 and 2. Port 1 is connected via a jumper cable221, e.g., 4-6 feet coaxial cable, to the tap250a. Port 2 is connected to network interface unit (NIU)210of customer premises53a. The NIU210, also referred to as a network interface device, typically is attached to the outside of the customer premises and is where the drop line connects to the in-home or in-customer-premises wiring. The NIU210is typically connected to a ground block and ground block measurements can be taken at the NIU210. The splitter211may be in the customer premises53aand is an impedance that reflects a reflectometry pulse output from the test instrument100as is further described below.

Connecting the test instrument100as shown inFIG. 2Acan be used to test wiring and signals at the tap250a, which may be at a node or telephone pole. For example, a reflectometry pulse is output at port 2 from the test instrument100to determine whether there is any impairments, such as broken cable, in the drop line220. Although a dual port test instrument is shown, the test instrument100may be a single port device. For example, the single port may be connected to the drop line220to measure signals on the drop line220.

FIG. 2Balso shows the test instrument100connected at a different test point, such as between the NIU210and the splitter211. From this test point, the test instrument100may take measurements to identify impairments at the customer premises53a. Similarly toFIG. 2A, prior to taking measurements to detect the impairments, the test instrument100determines whether port 2 is connected to a cable of a predetermined minimum length, such as the cable222connected to splitter211and may also determine if the signature of a reflected signal received at port 2 is different than a previous signature and/or specific to the current location or customer premises.FIGS. 2A-Bgive two examples of test points. Tests may be performed at other locations as discussed above.

FIGS. 3A-Bshow examples of components of the test instrument100, according to an example.FIG. 3Ashows an example of the test instrument100as a single port device with only port121to connect to network101to measure signals in the network101, andFIG. 3Bshows an example of the test instrument100as a dual port device with ports121and122to connect to the network101to measure signals. As shown inFIG. 3A, a signal processing circuit130, which may be connected to the port121, is configured for processing signals from the network101that are received via the port121to obtain measurement data139. A pulse generator131(e.g., TDR or FDR) generates reflectometry pulses which are output via port121and are reflected back to the port121from impedances in the network101. The reflected pulses, also referred to as reflected signals, are upstream signals measured by the signal processing circuit130to generate measurement data139. Downstream signals, such as downstream signals11shown inFIG. 1, may also be measured to generate measurement data139. A control processor150may be communicatively coupled to the signal processing circuit130and is configured to process the measurement data139and make the determinations described herein, such as to determine problems and suggested actions. The processor150may display measurements and notifications on display160. A keypad161, touch screen or another I/O device may be provided to receive user input. Interface162may include one or more communication interfaces, such as USB, Bluetooth, WiFi, etc. The signal processing circuit130and processor150may be embodied using a single dedicated or shared hardware processor or using multiple hardware processors, and/or a combination of software and hardware. Examples of hardware processors that may be used to implement the components including a digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), network processor, system on a chip, microprocessor, Complex Programmable Logic Device (CPLD), erasable programmable logic device (EPLD), simple programmable logic device (SPLD), or macrocell array. Data storage151may store measurement data, signatures or any information used by the test instrument100. In an example, one or more of the functions and steps of the methods may be performed by the processor150or other hardware executing machine readable instructions stored in a non-transitory computer readable medium, such as the data storage151. The data storage may comprise RAM (random access memory), ROM (read only memory), EPROM (erasable, programmable ROM), EEPROM (electrically erasable, programmable ROM), hard drives, flash memory, or other types of storage devices, which may be volatile and/or nonvolatile.

FIG. 3Bis similar toFIG. 3Abut includes additional port122connectable to the network101. Signal processing circuit140for processing signals from the network101that are received via the port122to obtain measurement data149. For example signal processing circuit130processes upstream signals, and signal processing circuit140processes downstream signals. Processor150process the measurement data139and149to make determinations described herein. The ports121and122allow the test instrument100to connect simultaneously to an upstream portion of the network101and to a downstream portion of the network101. The port121receives upstream signals and the port122receives downstream signals, and measurement data139is upstream measurement data and measurement data149is downstream measurement data. The test instrument100may perform parallel measurements on the upstream and downstream signals111,112respectively, and the measurement results simultaneously displayed.

FIG. 4shows additional details of the components of the test instrument100shown inFIG. 3Afor the single port example.FIG. 4shows pulse generator131, which may be a TDR or FDR reflectometer. The pulse generator131may be coupled to the signal processing circuit130and the port121. The pulse generator131injects a probe signal (e.g., reflectometry pulse146) into the network101through a coupler or switch142and port121. The signal processing circuit130may include reflectometer control logic for controlling the operation of pulse generator131and processing measurement results.

The components may include an optional gain control unit141that is operationally followed by an Analog to Digital Converter (ADC)143, a Digital Downconverter/Fast Fourier Transform (DDC/FFT) unit145, and signal processing circuit130. The DDC/FFT logic145may be configured to obtain a frequency spectrum of signal170(e.g., reflected signal) within the frequency band of transmission, for example by performing the FFT of170, and/or to tune to an active channel using digital down-conversion. The active channel to tune to may be selected, for example, by a user command or automatically by internal tester programming, and communicated to the DDC/FFT logic145by the control processor150and/or the signal processing circuit130.

The measurement data139related to signal170may include signal characteristics. The measurement data139may include frequency of each channel detected in the signal170, and may also include channel diagnostic information for one or more of the detected or active channels. The channel diagnostic information may include at least one of the following channel parameters or characteristic: signal level of the detected downstream channel, a modulation type of the detected downstream channel, signal-to-noise (SNR) for the channel, bit error ratio (BER) for the detected channel, modulation error ratio (MER) for the detected channel, ingress under the carrier, in Channel Frequency Response (ICFR), adaptive equalization coefficients, Digital Quality Index (DQI), etc.

FIG. 5shows details of the signal processing circuits130and140in the dual-port test instrument shown inFIG. 3A. Signal processing circuit140for processing downstream signals may include a frequency scan logic171for controlling the DDC/FFT and obtaining active channel data therefrom, and a QAM demodulator172for demodulating the selected downstream channel; the QAM demodulator172may include an adaptive equalizer. MPEG/DOCSIS decoder173decodes a demodulated signal received from the QAM demodulator172. Measurement control logic (MCL)175may read various performance-related data from the MPEG/DOCSIS decoder173, the QAM demodulator173and the channel scan control logic171to perform a variety of service level tests and to obtain the downstream signal characteristics. Obtaining the signal characteristics is further described in for example U.S. Pat. Nos. 5,751,766, 6,061,393, 6,385,237 and 7,792,183. By way of example, the MCL175may be configured to use output from the DDC/FFT for measurements of analog or digital channel level, downstream frequency response, constellation plots, and ingress under the carrier. Alternatively, the two later measurements can be performed by querying the QAM demodulator172. MCL175may also query control registers of the DDC/FFT to obtain DDC gain values, which may then be used for computing carrier level parameters and the like. The MPEG/DOCSIS decoder173may have rate counters and packet error counters that may be read by MCL175to measure pre-FEC and post-FEC Bit Error Rate (BER), and MPEG data stream errors or error rates for the selected DS channel. The channel scan logic171may be configured to operate under the control of MCL175, as auto-detection logic.

Signal processing circuit140may include frequency scan logic181for controlling the DDC/FFT and obtaining active channel data therefrom, and a QAM demodulator182for demodulating the selected upstream channel; the QAM demodulator182may include an adaptive equalizer. DOCSIS decoder183decodes demodulated signal received from the QAM demodulator182. Measurement control logic (MCL)185reads various performance-related data from the DOCSIS decoder183, the QAM demodulator183and the channel scan control logic181to perform a variety of service level tests and to obtain the upstream channel characteristics, as generally described above. T(F)DR184for example controls the pulse generator131to generates TDR or FDR pulses.

FIG. 6is similar toFIG. 4but shows the components for the dual-port test instrument ofFIG. 3B.FIG. 6includes some of the same components ofFIG. 4for measuring the upstream signals, such as signal170.FIG. 6also shows components for measuring downstream signals176. Gain191, ADC193and DDC/FFT195operate similarly to gain141, ADC143and DDC/FFT145. Also, port switch197may be disposed operatively between ports121and122on one side and signal processing circuits130and140on the other side, and may be configured for pair-wise connecting the ports121and122to the signal processing circuits130and140for supporting port auto-routing.

FIG. 7illustrates a method700for detecting a problem and determining a suggested action from correlated measurements. The method700and other methods described herein are described by way of example as being performed by the test instrument100shown inFIGS. 1-6, but the methods may be performed by other test instruments. Also, one or more steps may be performed in different orders or substantially simultaneously.

At701, at least one signal from the network101is measured by the test instrument100at one or more test points to determine measured characteristics of the at least one signal. The at least one signal may include upstream signals and/or downstream signal. For example, for upstream signal measurements, the pulse generator131generates reflectometry pulses (e.g., TDR or FDR pulses) which are output via a port, such as port121. For example, the reflectometry pulses are output downstream in the network101, such as towards a customer premises or internally in the customer premises. The reflectometry pulses are reflected by impedances and characteristics of the reflected signals, such as amplitude and reflection time, i.e., the time it takes for the pulse to return to the port, signal level, frequency response, etc. are measured to detect impairments. Upstream signal characteristics may also be measured. For example, the port122may be connected to the network101to receive upstream signals which are measured.

The test instruments100may run multiple tests that determine multiple characteristics of the measured signals for identifying problems on a channel. According to an example, the multiple tests are automatically run in the background, and the running of the tests may be invoked by the user clicking a button on the test instrument, which is further described in the examples discussed below. Examples of signal characteristics measured by the tests include power level, adjacent channel power level, smart scan for tilt and system levels, Bit Error Ratio (BER) and Modulation Error Ratio (MER), Digital Quality Index (DQI), Ingress Under Carrier, Equalizer—Echos, In Channel Response, Group Delay, Digital Hum, Automatic Gain Control (AGC) Stress, Constellation Analysis—coherent interference, and channel noise. The signal characteristics may be measured in a predetermined order (or user-selected) or substantially simultaneously.

The test instrument100may measure signal characteristics for a single channel or multiple channels.FIG. 8Ashows an example of information that may be presented on the display160by the processor150for single channel problem detection. As shown, the problems detected from the measured signal characteristics may include intermittent performance, noise, echo/reflection, and frequency response. A button may be pressed by a user for suggested actions.

For multi-channel testing, the test instrument100may scan through channels and measure characteristics for the different channels in order to identify problems in the network101that the user might not presently be focused on. To identify problems faster, the test instrument100may prioritize both the measurements (i.e., the measurement of the signal characteristics) and the channels that are measured. The user may select the order for measuring the channels and/or the order for measuring the signal characteristics or the orders may be predetermined. The processor150can provide visual feedback of the progress and present the measurements, detected problems, suggested actions, etc., on the display160as the measurements are performed on the channels. Thus, the user does not have to wait until completion to take action, and the user can stop the measurements and take action as needed. The test instrument100can save the measurements and allow the user to retest and compare, which may be performed through a guided process.FIG. 8Bshows an example of information that may be displayed on the display160for multi-channel testing. It provides visual feedback of the testing prior to and after completion of the testing of each channel. For example, the visual feedback may indicate for each problem detected or checked, the number of channels and severity of the problem. Also, a retest button may be provided to facilitate the retest.

Also, as discussed above, the measurements may be performed at different test points. Test points may include but are not limited to the tap, ground block and customer premises.

At702, the measured characteristics are correlated to detect one or more problems in the network101and determine a suggested action for each problem. Measurements performed for a particular channel at one or more locations (i.e., test points) may be correlated, and the measurements may be for upstream and/or downstream signals. Correlating the measured characteristics may include determining a relationship between a plurality of the measured characteristics that may be indicative of a problem in the network101. In an example, the relationships are determined and stored in a table. A table is any data structure that can store the relationships. A lookup may be performed on the table to detect a problem based on the measured characteristics and a suggested action corresponding to the problem.

The table may include subsets of measured characteristics that are indicative of different problems and corresponding suggested actions. For example, each subset of measured characteristics that are out of tolerance are associated with a particular problem and a suggested action. An out of tolerance characteristic may be greater than or less than a predetermined threshold and if the threshold is exceeded it may be at least partially indicative of a problem. A subset of measured characteristics may include a plurality of the measured characteristics but may be less than all the measured characteristics.

FIGS. 9A-Cillustrate examples of portions of a table that may be used to identify problems and suggested actions based on subsets of measured characteristics that are out of tolerance.FIG. 9Ashows a portion of a table related to a detected signal quality problem903and is for measured characteristics901that are measured at the tap and other test points. As shown, the measured characteristics may include measurements for digital and analog signals. For the signal quality problem903, the subset of measured characteristics are shown as902and are marked with an “X”, e.g., MER, BER, and C/N (channel noise). If these measured characteristics are out of tolerance, it is indicative of a signal quality problem. The table also includes suggested actions, examples of which are shown inFIG. 9A. Suggested actions904are the suggested actions that may be presented if the signal quality problem is detected.

FIGS. 9B and 9Care for measured characteristics that are measured at the ground block and at the customer premises, respectively.FIGS. 9B and 9Calso show the subset of out of tolerance characteristics912and922that are indicative of a signal quality problem at the respective test point. Suggested actions914and924are also shown and may be different for different test points. Multiple suggested actions may be associated with a single detected problem.

To determine the detected problem and the associated suggested action, the out of tolerance measured characteristics are determined. A lookup may be performed in the table with the out of tolerance measured characteristics to determine whether they are in a subset of measured characteristics for a problem. If the out of tolerance measured characteristics are in a subset of measured characteristics for a problem, the problem associated with the subset is the detected problem and an associated suggested action is determined from the table. In an example, all the measured characteristics in the subset must be out of tolerance to be indicative of the problem. For example, all of MER, BER and C/N must be out of tolerance to be indicative of a signal quality problem. In another example, a majority or multiple of the measured characteristics in the subset must be out of tolerance to be indicative of the associated problem. The results of the lookup for example include the detected problem or problems and one or more suggested actions for each detected problem.

At703, any problems that are determined and one or more suggested actions for each problem are displayed on the display160. Also, the out of tolerance characteristics, determined problems and associated suggested actions may be transmitted to a remote computer such as via the communications interface162.

The table discussed above with respect to702may be stored at the test instrument100, such as in the data storage151. The measurements are performed for example by signal processing circuits130and140, and the processor150may identify measured characteristics that are out of tolerance. The processor150may determine whether there is a problem that is associated with the out of tolerance characteristics, such as described above, based on information in the table, and identify one or more suggested actions for each determined problem from the table. The measured characteristics, problems and suggested actions may be displayed on the display160.

The analysis of the measured characteristics may also be performed by a remoter computer. For example, the processor may send the measured characteristics and/or an indication of the out of tolerance characteristics to the remote computer via the communications interface162in a request for problem detection. The remote computer may store the table and perform a lookup in the table to identify any problems and corresponding suggested actions, such as described above. The test instrument100may receive the identified problems and corresponding suggested actions via the communications interface162from the remote computer and display the information.

FIGS. 9A-Cshow examples of measured characteristics that are indicative of a signal quality problem. The table may store subsets of measured characteristics for other problems and corresponding suggested actions. Some examples of other identifiable problems that may be stored in the table include but are not limited to downstream ingress, level deviations, distortions/echoes/reflection, in band AGC problem, headend modulator problem, voltage problem, bad CPE, downstream packet loss, downstream throughput, upstream packet loss, upstream ingress, upstream ICFR, transmission levels and throughput, and DOCSIS problems.

FIGS. 10-14show examples of screen shots that may be generated by the processor150and displayed on the display160of the test instrument100. As discussed above, the test instrument100may execute multiple tests for a session. The tests may be invoked by a user entering information for the session in the test instrument and clicking a button to invoke the measurements for a test point.FIG. 10shows a screen for entering the test location, which is the tap in this example, and entering a work order ID, also referred to as a session ID. Then, the user may click the start button to execute the tests to measure the signal characteristics.

As shown inFIG. 11, after the user starts the tests, they are presented with a summary dashboard of the automated test results and a summary panel of the session (shown as Session Expert at the bottom). For example, the summary panel includes arrow summarizing indicating the service performance at various test points. The arrows indicate which direction the impairments are coming from, upstream or downstream, and also show the pass/fail or health of the service, which may be indicated by color (green and check mark for Okay, Red and X for Bad, or Greyed out for portions not tested). Additional details may be displayed by selecting the summary panel, either by touching on the touchscreen or navigating via keypad and selecting enter with the keypad. Upon selecting the summary panel, the user is provided with a top level summary of the problems detected and the suggested actions.

FIG. 12shows an example of session details including problems detected and suggested actions for the tap test point, andFIG. 13shows problems detected and suggested actions for the ground block test point. The user has the ability to choose a different test point, such as tap, ground block or CPE, by selecting the tab at the top of the screen to view the problems detected at other test points.

The user may also be provided with additional details and analysis based on the tests performed at multiple test points. One measurement in particular is identifying problems in the drop (the coaxial cable between the TAP and Ground Block) based on background TDR or FDR measurements. These results are provided to the technician in a panel within the detailed view, such as shown inFIG. 14.

Although not shown, the test instrument100may generate displays for drop analysis which may be performed by TDR or FDR reflectometry. For example, pattern matching of unique reflections identified at the ground block and tap are performed. Also, the distance estimates are determined to estimate the length of the drop. The signatures and other measurements may be displayed for comparison. Additionally, the test instrument may display test results for multiple test points on a single screen for easy comparison.