Specifications
A-6 GB1400 User Manual
Data Patterns
Format NRZ-L
Type PRBS or WORD (User-programmable)
PRSB Patterns 2
n-1
where n =7,15,17,20,23
WORD Length 8- and 16-bit only,
1 Mbit with optional memory
PRBS Phase Tap Information
The Pseudo-Random data patterns used in the GB1400 RX are generated by shift-register and
exclusive-OR feedback technique. The pattern is dependent on which feedback taps (shift register
outputs) are selected.
For example, PN7 is defined as a seven-stage shift register, which the output of stages 6 and 7 fed
back (through an exclusive-OR gate) to the beginning of the shift register. The feedback taps used
in the GB1400 are tabulated here.
Pattern Feedback Taps
PN7 6 7
PN15 14 15
PN17 14 17
PN20 17 20
PN23 18 23
Reference Data Input
Format NRZ-L true
Data Rate 1 Mb/s to 1400 Mb/s
Input Threshold Variable, -1.5 V to +1.0 V, 50 mV steps
Input Level 0.5V to 1.5Vp-p
Impedance 50 Ohms
Termination Voltage Selectable, Gnd, -2.0V or AC
Delay Range 0-3.90 ns, variable, in 100 pS steps
Connectors SMA