Abstract: A method and a testing device for determining signal-to-noise headroom of a pair of conductors are provided. In the method and testing device, a gain of electric signal transmissions over a pair of conductors is varied to reach a first gain. Prior to reaching the first gain a transition between reception failure and successful reception of the electric signal transmissions does not occur. A first electric signal having the first gain is transmitted over a first end of the pair of conductors and it is determined that the transition between reception failure and successful reception of the first electric signal occurred. A signal-to-noise ratio (SNR) headroom for the pair of conductors is determined based on the first gain at which the transition between reception failure and successful reception occurred.

Abstract: A network analyzer includes a main unit and a physically separate remote unit. In at least one configuration, the main unit generates and transmits test signals through a device under test to the remote unit. Reference circuitry in the main unit uses signals from a local oscillator and an analog-to-digital ADC sample clock to produce reference signal data representative of the test signals as transmitted to the device under test. Receive circuitry in the remote unit produces received signal data representative of the test signals as received from the device under test, using the same signals from the local oscillator and ADC sample clock as used by the reference circuitry to produce the reference signal data. Comparison of the received signal data with the reference signal data indicates parameters of the device under test, including attenuation and phase shift in the test signals as caused by the device under test.

Abstract: A network analyzer includes a main unit and a physically separate remote unit. In at least one configuration, the main unit generates and transmits test signals through a device under test to the remote unit. Reference circuitry in the main unit uses signals from a local oscillator and an analog-to-digital ADC sample clock to produce reference signal data representative of the test signals as transmitted to the device under test. Receive circuitry in the remote unit produces received signal data representative of the test signals as received from the device under test, using the same signals from the local oscillator and ADC sample clock as used by the reference circuitry to produce the reference signal data. Comparison of the received signal data with the reference signal data indicates parameters of the device under test, including attenuation and phase shift in the test signals as caused by the device under test.

Abstract: A method and apparatus for tuning crosstalk and return loss are provided. In the method and apparatus, a filter tunes return loss caused by a first external terminal and a second external terminal to compensate for a capacitive load induced by sizes of and a proximity between the first and second external terminals. The filter decouples the tuning of the return loss from tuning a magnitude and a phase of a crosstalk between a first transmission line network and a second transmission line network such that the return loss is tuned with minimal impact on the crosstalk.

Abstract: A method and apparatus for tuning crosstalk and return loss are provided. In the method and apparatus, a filter tunes return loss caused by a first external terminal and a second external terminal to compensate for a capacitive load induced by sizes of and a proximity between the first and second external terminals. The filter decouples the tuning of the return loss from tuning a magnitude and a phase of a crosstalk between a first transmission line network and a second transmission line network such that the return loss is tuned with minimal impact on the crosstalk.

Abstract: A method and apparatus are provided for determining which path of a network transmission link having a receive path and a transmit path is carrying receive signals, and then automatically configuring a network tester such that an internal transmitter and an internal receiver match the transmit and receive paths of the network. Initially, both paths are monitored by the tester's receiver to determine whether there is traffic on the network. Then the tester automatically configures its interface to designate a first one of the paths as the receive path, and tests this configuration to determine whether the internal receiver receives a signal. If a signal is received, the configuration is verified. If no signal is received, the tester reconfigures the interface to designate the other path as the receive path. Once the network receive path is identified, the tester automatically configures its interface such that the transmit path is set opposite the receive path.