There are provided a data comparison unit that detects an FEC symbol error of a signal under test output from a DUT in accordance with an input of a jitter signal, an error counting unit that counts the number of detected FEC symbol errors for each codeword for each phase modulation amount, a codeword classification unit that classifies a plurality of codewords included in the signal under test into a plurality of groups based on the counted number of FEC symbol errors, a codeword number counting unit that counts the number of codewords in each group for each phase modulation amount, and a display control unit that controls a display of a first graph having a horizontal axis as the phase modulation amount and a vertical axis as a ratio of the number of codewords in each group, on a display screen.

Systems, apparatuses, and methods for implementing asynchronous feedback training sequences are described. A transmitter transmits a training sequence indication to a receiver via a communication channel including a plurality of data lines. The training sequence indication includes a bit sequence to indicate the beginning of a training sequence. The indication includes a transition from a zero to a one at the midpoint of a supercycle of ‘N’ clock cycles in length, followed by a predetermined number of ones. The training sequence indication is then followed by a test pattern. The beginning of the test pattern occurs at the end of a supercycle. The receiver determines if there are any errors in the received test pattern, and then sends feedback to the transmitter that indicates whether any errors were detected. Responsive to receiving the feedback, the transmitter alters delay settings for one or more of the data lines.

One embodiment provides an apparatus. The example apparatus includes a root mean square (RMS) distortion determination module configured to determine an RMS distortion error and a signal to noise and distortion ratio (SNDR), the RMS distortion error determined based, at least in part, on a portion of a transmitted pulse centered at or near a transmitted pulse maximum amplitude and the SNDR determined based, at least in part, on the RMS distortion error.

A system and method employ an exclusive-OR gate having a first input configured to receive an RF carrier signal having an RF carrier, and a second input configured to receive a square wave signal having a square wave frequency, to output to a signal processing channel under test a binary phase shift keying (BPSK) signal comprising the RF carrier signal modulated by the square wave signal. A digital signal processor is configured to receive from the signal processing channel in-phase (I) and quadrature-phase (Q) data produced by the signal processing channel in response to the BPSK signal, and to process the I and Q data to determine an amplitude response and phase response of the signal processing channel as a function of frequency.

An apparatus and method relate generally to generation and checking of a quaternary pseudo random binary sequence (“QPRBS”). In an apparatus, there is a pseudo random binary sequence (“PRBS”) generator configured to receive a seed of a PRBS to be generated. A mask generator is configured to generate a mask output corresponding to the PRBS. The PRBS generator and the mask generator are both configured for sequential operation with respect to one another. A masking circuit is configured to receive the mask output and the PRBS to bitwise mask the PRBS with the mask output to generate the QPRBS.

A method for wireless communications testing using downlink (DL) signal transmissions from an access point to a mobile terminal and uplink (UL) signal transmissions from said mobile terminal to said access point. Accurate block error rate (BLER) testing of LTE mobile devices in a wireless signal environment is enabled by preventing repeated transmissions of the same downlink (DL) data block that would normally follow reception of uplink (UL) transmissions of negative UL acknowledgments (NACKs) caused by failures to decode prior DL data transmissions, thereby producing cumulative NACK counts accurately reflecting data reception errors.

Provided is a PIM detection apparatus including: a tone signal input unit configured to apply a tone signal having a first frequency characteristic to a test target apparatus; a sequence signal input unit configured to apply a sequence signal having a second frequency characteristic to the test target apparatus; a PIM detector configured to receive a Passive Intermodulation (PIM) signal from the test target apparatus, and to detect a delay time and a size of the PIM signal based on the sequence signal; and a PIM position determiner configured to determine a PIM occurrence position by using the delay time and the size of the PIM signal.

A test apparatus is configured to perform non-determinative testing of equipment. The test apparatus comprises a test computer arranged to automatically execute a non determinative test regime under the control of a test application. A network simulator connected to the test computer is provided with communication circuitry operable to communicate with the equipment under test. The network simulator is configurable into different network states according to the non-determinative test regime, and the test application is operable to control the network simulator to transition between a plurality of different network states. Data about unscripted communications between the network simulator and the equipment under test is monitored and can be analyzed to reach a test verdict.

Systems, methods, and circuitries are provided to measure a swept error power ratio (SWEEPR) of a device under test. A method includes generating a time-variant stopband test signal having a time-variant stopband and determining an error of the device under test based on an output signal generated by the device under test in response to the time-variant stopband test signal.

A test instrument or host device can apply inverse transmitter and receiver functions to data transmitted or received by an electrical and optical transponder. The inverse transmitter and receiver functions are applied to counteract internal signal conversion processes of the transponder. Forward error correction and test pattern analysis may be performed on signals received from the transponder after the inverse receiver function is applied to the received signals.