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M8048A ISI Channels

Data Sheets

M8048A ISI Channels

Master Your Next Designs

Key features

− Emulate a wide range of channel loss with cascadable ISI traces with fine resolution

− 4 short (7.7” to 12.8“) and 4 long traces (14.4” to 34.4”)

− Real Nelco FR4 PC board material with known S21 parameters

− Differential channels

− Supplementary to Keysight’s compliant ISI channels (PCIe®, SATA, DP, HDMI)

− Small size


The M8048A ISI Channels can be used to emulate channel loss in receiver test setups. A choice of 8

PC board traces with different lengths can be inserted into the signal path. The 8 trace lengths range

from 7.7 inch (196 mm) to 34.4 inch (874 mm). By cascading the traces within one box or with the

other box a wide range of channels can be emulated with very fine resolution steps. With their small

size the ISI channels can be located closely to the device under test. The cascadable ISI channels

are complemented by the Keysight Technologies, Inc. compliance channels for SATA, DisplayPort,

PCI Express®, and HDMI.

Emulate channel loss

The channel loss between transmitter and receiver is a critical element for the receiver test for all

electrical multi gigabit serial interfaces. The channel loss depends primarily on the distance between

transmitter and receiver and the electrical medium. The channel loss is typically defined by the S21

parameter in dB for certain frequencies. Some standards define the receiver test to include a certain

channel loss in the test setup. M8048A offers a wide range of cascadable channels to emulate certain

S21 parameter conditions in a repeatable and accurate way.

Emulate intersymbol interference

Low-cost Nelco FR4 PC board material is very commonly used in many consumer and computer

products. Long electrical cables are also very common (HDMI, DisplayPort and USB) for connecting

consumer and computing devices. With increasing bit rates the signal degradations caused by the

channel become a critical part for the receiver characterization and compliance test. The so-called

intersymbol interference (ISI) caused by the channel degradation is a data dependant jitter or a

bounded deterministic jitter. The ISI jitter added by a PC board trace not only depends on the trace

length and the PC board material, but also depends on the data rate and the transmitted bit pattern.

The ISI jitter a receiver must tolerate is typically defined in ps or mUI by each standard for the

required bit rate and compliance pattern.

Application examples


− USB3


− Thunderbolt


− DisplayPort

− PCI Express

M8048A specifications

Specification assumptions

The specifications in this document describe the instruments performance. All specifications if not otherwise stated are valid using the recommended cable set M8041A-801 (2.92 mm, 0.85 m, matched pair).


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