10Gb/s SFP+ Direct Attach copper cable have two choice: passive and active cable.
Passive SFP+ DAC cable assembly allows for a serial data transmission up to 120Gbps, which is a low cost choice for very short reach applications of 10GbE.
The design of passive SFP+ DAC cable has no signal amplification and CDR in the cable assembly. EDC (Electronic Dispersion Compensation) is typically used on host board designs when passive copper cable assemblies are utilized. EDC allows for an extended length of passive cable assemblies.
Now, let us go to High Speed Electrical Measurements
SFF-8431 has many requirements for how to test a SFP+ Cables.
VMA and VCR Measurements,
SDD11 and SCC11 Measurements for differential and common mode return loss,
Return loss measurements were measured on a VNA with the module compliance test boards.
The following is the test item for a typical SFP+ Passive cable:
Differential Insertion Loss (SDD21 & SDD12)
Differential Return Loss (SDD11 & SDD22)
Differential to Common Mode Conversion (SCD21 & SCD12)
Differential Imbalance (SDD31 and SDD42 when driven differentially)
TDT Skew (Intra-Pair & Inter-Pair),
Extracted Eye Pattern
Ability to add equalizer in eye pattern measurement for high speed systems
Measured PRBS Eye Pattern (Up to 12.5 Gbps)
10Gtek is the global leading supplier of transceiver & twinax cable, it has established complete test process and automatic test system to ensure its products 100% in accordance with the requirements of SFF-8431 standards for production test.
Apart from SFP+ Cable supplying SFP+ Passive cables, 10Gtek also offers SFP+ Active Cable，QSFP+ Cables，QSFP+ AOC etc. high speed interconnection products.