Abstract: Briefly, a method and system is provided for testing a cable using a high performance Time Domain Reflectometry (TRD) system and method. The TDR has a timing generator that is constructed to generate a periodic launch pulse to excite a cable under test, and to generate sample signals that are time delayed from the launch pulse. The timing for the launch pulse and the sample signal may be defined by two correlated PLL circuits coupled to the same clock. In one implementation, the timing generator is constructed in a single FPGA. The invention also provides calibration circuitry to compensate for temperature, voltage, and manufacturing variations in the FPGA. In one example, a tester includes a switch system that enables one or more TDR engines to sequentially apply a TDR stimulus to substantially all the wire pairs in a cable harness, and to collect the resulting TDR waveforms. The waveforms are analyzed to determine if the cable harness meets quality standards.

Abstract: Briefly, a method and system for testing a cable harness is disclosed. Generally, a cable harness is used to route many electric wires for power, communication, and control. The tester includes a switch system that enables one or more TDR engines to sequentially apply a TDR stimulus to substantially all the wire pairs in the cable harness, and to collect the resulting TDR waveforms. The waveforms are analyzed to determine if the cable harness meets quality standards. In some cases the tester may also perform a continuity, resistance, capacitance, or inductance test on the cable harness. The tester may also measure and use temperature in analyzing the cable harness, or may apply temperature cycling, different or varying atmospheric pressures, vibration, shaking, or shock to the cable harness.

Abstract: Briefly, a method and system for testing a cable harness is disclosed. Generally, a cable harness is used to route many electric wires for power, communication, and control. The tester includes a switch system that enables one or more TDR engines to sequentially apply a TDR stimulus to substantially all the wire pairs in the cable harness, and to collect the resulting TDR waveforms. The waveforms are analyzed to determine if the cable harness meets quality standards. In some cases the tester may also perform a continuity, resistance, capacitance, or inductance test on the cable harness. The tester may also measure and use temperature in analyzing the cable harness, or may apply temperature cycling, different or varying atmospheric pressures, vibration, shaking, or shock to the cable harness.

Abstract: A digital time domain reflectometer system is provided for performing a measurement process that is useful for calculating a cable length. The measurement process starts with a launch controller periodically generating a sync signal for turning a duration signal on. After a known delay time, the launch controller launches a signal on a cable, and if a reflected signal is detected, a detection circuit turns the duration signal off. A counter counts the number of clock pulses in the duration signal. This system is made more accurate by performing the measurement process multiple times and averaging the results. Using the averaged results, and compensating for the added known delay time, the cable length is calculated. An adaptive threshold may be used to enhance measurement accuracy.

Abstract: The tone generator uses a highly accurate frequency signal to generate an accurate and stable tone signal. A cadence pattern may be used to output the tone signal onto a test cable in an easily distinguishable pattern. The tone signal may be selectively output at an in-band band frequency or an out-band frequency. A corresponding tone probe may be used to detect the tone signal. The tone probe uses a high-Q bandpass filter to reject all but the expected frequency of the tone signal. The signal passing the bandpass filter is proportional to the detected tone signal. The tone probe generates an audio signal unrelated to the frequency of the tone signal. The audio signal is modulated by the signal from the bandpass filter, and then broadcast through a speaker. Accordingly, the tone probe provides an audible sound proportional to the strength of the tone signal, but is unrelated in frequency.

Abstract: The tone generator uses a highly accurate frequency signal to generate an accurate and stable tone signal. A cadence pattern may be used to output the tone signal onto a test cable in an easily distinguishable pattern. The tone signal may be selectively output at an in-band band frequency or an out-band frequency. A corresponding tone probe may be used to detect the tone signal. The tone probe uses a high-Q bandpass filter to reject all but the expected frequency of the tone signal. The signal passing the bandpass filter is proportional to the detected tone signal. The tone probe generates an audio signal unrelated to the frequency of the tone signal. The audio signal is modulated by the signal from the bandpass filter, and then broadcast through a speaker. Accordingly, the tone probe provides an audible sound proportional to the strength of the tone signal, but is unrelated in frequency.

Abstract: The tone generator uses a highly accurate frequency signal to generate an accurate and stable tone signal. A cadence pattern may be used to output the tone signal onto a test cable in an easily distinguishable pattern. The tone signal may be selectively output at an in-band band frequency or an out-band frequency. A corresponding tone probe may be used to detect the tone signal. The tone probe uses a high-Q bandpass filter to reject all but the expected frequency of the tone signal. The signal passing the bandpass filter is proportional to the detected tone signal. The tone probe generates an audio signal unrelated to the frequency of the tone signal. The audio signal is modulated by the signal from the bandpass filter, and then broadcast through a speaker. Accordingly, the tone probe provides an audible sound proportional to the strength of the tone signal, but is unrelated in frequency.

Abstract: A portable and handheld communications tester is provided. The communications tester conveniently simulates a DHCP client for establishing communication with a DHCP server. Accordingly, the communications tester exchanges standardized DHCP messages with the server to be assigned a dynamic IP address. The communications tester thereby verifies operational connectivity with the DHCP server. The communications tester may be arranged with particular physical connectors for connecting to Ethernet, DSL, fiber optic, and/or coaxial cables. Further, the communications tester may have an optional integral modem for providing modulation and demodulation on the communication cable. In a particular example of the communications tester, the communications tester also incorporates a PING function for interrogating IP devices along the communication link. The tester may also employ BERT, Stress and other testing functions to further characterize and verify the robustness of the communication connection.

Abstract: The tone generator uses a highly accurate frequency signal to generate an accurate and stable tone signal. A cadence pattern may be used to output the tone signal onto a test cable in an easily distinguishable pattern. The tone signal may be selectively output at an in-band band frequency or an out-band frequency. A corresponding tone probe may be used to detect the tone signal. The tone probe uses a high-Q bandpass filter to reject all but the expected frequency of the tone signal. The signal passing the bandpass filter is proportional to the detected tone signal. The tone probe generates an audio signal unrelated to the frequency of the tone signal. The audio signal is modulated by the signal from the bandpass filter, and then broadcast through a speaker. Accordingly, the tone probe provides an audible sound proportional to the strength of the tone signal, but is unrelated in frequency.

Abstract: A network link tester couples to a LAN port with the LAN port having both a network transmit pair and a node transmit pair line. The link detector scans the network transmit pair and node transmit pair lines for the presence of link signals. Upon finding a link signal, the link tester indicates if the link signals were on the network transmit pair or on the node transmit pair line. Further, the link tester determines the network standard used and identifies the available operational nodes. The process of using a LAN tester includes coupling the tester to the LAN port, scanning network lines for the presence of link signals and determining and displaying operational capabilities. Optionally, the link tester may generate a tone signal on the network lines to assist in identifying line faults. Further, the link tester may generate link signals responsive to receive link signals.